This file is indexed.

/usr/share/doc/slony1-2-doc/adminguide/appendix.html is in slony1-2-doc 2.2.4-3.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   1
   2
   3
   4
   5
   6
   7
   8
   9
  10
  11
  12
  13
  14
  15
  16
  17
  18
  19
  20
  21
  22
  23
  24
  25
  26
  27
  28
  29
  30
  31
  32
  33
  34
  35
  36
  37
  38
  39
  40
  41
  42
  43
  44
  45
  46
  47
  48
  49
  50
  51
  52
  53
  54
  55
  56
  57
  58
  59
  60
  61
  62
  63
  64
  65
  66
  67
  68
  69
  70
  71
  72
  73
  74
  75
  76
  77
  78
  79
  80
  81
  82
  83
  84
  85
  86
  87
  88
  89
  90
  91
  92
  93
  94
  95
  96
  97
  98
  99
 100
 101
 102
 103
 104
 105
 106
 107
 108
 109
 110
 111
 112
 113
 114
 115
 116
 117
 118
 119
 120
 121
 122
 123
 124
 125
 126
 127
 128
 129
 130
 131
 132
 133
 134
 135
 136
 137
 138
 139
 140
 141
 142
 143
 144
 145
 146
 147
 148
 149
 150
 151
 152
 153
 154
 155
 156
 157
 158
 159
 160
 161
 162
 163
 164
 165
 166
 167
 168
 169
 170
 171
 172
 173
 174
 175
 176
 177
 178
 179
 180
 181
 182
 183
 184
 185
 186
 187
 188
 189
 190
 191
 192
 193
 194
 195
 196
 197
 198
 199
 200
 201
 202
 203
 204
 205
 206
 207
 208
 209
 210
 211
 212
 213
 214
 215
 216
 217
 218
 219
 220
 221
 222
 223
 224
 225
 226
 227
 228
 229
 230
 231
 232
 233
 234
 235
 236
 237
 238
 239
 240
 241
 242
 243
 244
 245
 246
 247
 248
 249
 250
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN""http://www.w3.org/TR/html4/loose.dtd">
<HTML
><HEAD
><TITLE
>Appendix</TITLE
><META
NAME="GENERATOR"
CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK
REV="MADE"
HREF="mailto:slony1-general@lists.slony.info"><LINK
REL="HOME"
TITLE="Slony-I 2.2.4 Documentation"
HREF="index.html"><LINK
REL="PREVIOUS"
TITLE="slony_logshipping"
HREF="slony-logshipping.html"><LINK
REL="NEXT"
TITLE=" Release Checklist "
HREF="releasechecklist.html"><LINK
REL="STYLESHEET"
TYPE="text/css"
HREF="stylesheet.css"><META
HTTP-EQUIV="Content-Type"
CONTENT="text/html; charset=ISO-8859-1"></HEAD
><BODY
CLASS="CHAPTER"
><DIV
CLASS="NAVHEADER"
><TABLE
SUMMARY="Header navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TH
COLSPAN="5"
ALIGN="center"
VALIGN="bottom"
><SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 2.2.4 Documentation</TH
></TR
><TR
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="slony-logshipping.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="10%"
ALIGN="left"
VALIGN="top"
><A
HREF="reference.html"
>Fast Backward</A
></TD
><TD
WIDTH="60%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="schema.html"
>Fast Forward</A
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="top"
><A
HREF="releasechecklist.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><DIV
CLASS="CHAPTER"
><H1
><A
NAME="APPENDIX"
></A
>Chapter 7. Appendix</H1
><DIV
CLASS="TOC"
><DL
><DT
><B
>Table of Contents</B
></DT
><DT
>7.1. <A
HREF="appendix.html#FAQ"
>Frequently Asked Questions</A
></DT
><DT
>7.2. <A
HREF="releasechecklist.html"
>Release Checklist</A
></DT
><DT
>7.3. <A
HREF="usingslonik.html"
>Using Slonik</A
></DT
><DT
>7.4. <A
HREF="slonikshell.html"
>Embedding Slonik in Shell Scripts</A
></DT
><DT
>7.5. <A
HREF="help.html"
>More <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> Help</A
></DT
><DD
><DL
><DT
>7.5.1. <A
HREF="help.html#AEN10183"
><SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> Website</A
></DT
><DT
>7.5.2. <A
HREF="help.html#AEN10190"
>Mailing Lists</A
></DT
><DT
>7.5.3. <A
HREF="help.html#AEN10209"
>Other Sources</A
></DT
></DL
></DD
></DL
></DIV
><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="FAQ"
>7.1. Frequently Asked Questions</A
></H1
><DIV
CLASS="QANDASET"
><DL
><DT
>1. <A
HREF="appendix.html#FAQCOMPILING"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Building and Installing <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> </A
></DT
><DD
><DL
><DT
>7.1.1.1. <A
HREF="appendix.html#AEN8374"
> I am using <SPAN
CLASS="PRODUCTNAME"
> Frotznik Freenix
4.5</SPAN
>, with its <ACRONYM
CLASS="ACRONYM"
>FFPM</ACRONYM
> (Frotznik Freenix
Package Manager) package management system.  It comes with
<ACRONYM
CLASS="ACRONYM"
>FFPM</ACRONYM
> packages for <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 7.4.7, which are what
I am using for my databases, but they don't include <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> in the
packaging.  How do I add <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to this?  </A
></DT
><DT
>7.1.1.2. <A
HREF="appendix.html#AEN8461"
> Problem building on Fedora/x86-64 </A
></DT
><DT
>7.1.1.3. <A
HREF="appendix.html#AEN8489"
> I found conflicting types for <TT
CLASS="ENVAR"
>yyleng</TT
>
between <TT
CLASS="FILENAME"
>parser.c</TT
> and <TT
CLASS="FILENAME"
>scan.c</TT
>.
In one case, it used type <TT
CLASS="TYPE"
>int</TT
>, conflicting with
<TT
CLASS="TYPE"
>yy_size_t</TT
>.  What shall I do?</A
></DT
></DL
></DD
><DT
>2. <A
HREF="appendix.html#FAQHOWTO"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: How Do I? </A
></DT
><DD
><DL
><DT
>7.1.2.1. <A
HREF="appendix.html#AEN8521"
> I need to dump a database
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>without</I
></SPAN
> getting <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> configuration
(<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>e.g.</I
></SPAN
> - triggers, functions, and such). </A
></DT
><DT
>7.1.2.2. <A
HREF="appendix.html#AEN8570"
> How should I run <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes? </A
></DT
><DT
>7.1.2.3. <A
HREF="appendix.html#AEN8612"
> I'd like to renumber the node numbers in my cluster.
How can I renumber nodes? </A
></DT
></DL
></DD
><DT
>3. <A
HREF="appendix.html#FAQIMPOSSIBILITIES"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Impossible Things People Try </A
></DT
><DD
><DL
><DT
>7.1.3.1. <A
HREF="appendix.html#AEN8629"
> Can I use <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to replicate changes back and
forth on my database between my two offices? </A
></DT
><DT
>7.1.3.2. <A
HREF="appendix.html#AEN8641"
> I want to replicate all of the databases for a
shared-database system I am managing.  There are multiple databases,
being used by my customers.  </A
></DT
><DT
>7.1.3.3. <A
HREF="appendix.html#AEN8657"
> I want to be able to make DDL changes, and have them replicated automatically. </A
></DT
><DT
>7.1.3.4. <A
HREF="appendix.html#AEN8671"
> I want to split my cluster into disjoint partitions
that are not aware of one another.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> keeps generating <A
HREF="listenpaths.html"
>Section 4.2</A
> that link those partitions together. </A
></DT
><DT
>7.1.3.5. <A
HREF="appendix.html#AEN8679"
> I want to change some of my node numbers.  How do I <SPAN
CLASS="QUOTE"
>"rename"</SPAN
> a node to have a different node number? </A
></DT
><DT
>7.1.3.6. <A
HREF="appendix.html#AEN8686"
> My application uses OID attributes; is it possible to replicate tables like this? </A
></DT
></DL
></DD
><DT
>4. <A
HREF="appendix.html#FAQCONNECTIONS"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Connection Issues </A
></DT
><DD
><DL
><DT
>7.1.4.1. <A
HREF="appendix.html#AEN8706"
>I looked for the <TT
CLASS="ENVAR"
>_clustername</TT
> namespace, and
it wasn't there.</A
></DT
><DT
>7.1.4.2. <A
HREF="appendix.html#AEN8717"
> I'm trying to get a slave subscribed, and get the
following messages in the logs:

</P><PRE
CLASS="SCREEN"
>DEBUG1 copy_set 1
DEBUG1 remoteWorkerThread_1: connected to provider DB
WARN	remoteWorkerThread_1: transactions earlier than XID 127314958 are still in progress
WARN	remoteWorkerThread_1: data copy for set 1 failed - sleep 60 seconds</PRE
><P></A
></DT
><DT
>7.1.4.3. <A
HREF="appendix.html#AEN8734"
>Same as the above.  What I forgot to mention, as well,
was that I was trying to add <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>TWO</I
></SPAN
> subscribers,
concurrently.</A
></DT
><DT
>7.1.4.4. <A
HREF="appendix.html#AEN8748"
> We got bitten by
something we didn't foresee when completely uninstalling a slony
replication cluster from the master and slave...</A
></DT
><DT
>7.1.4.5. <A
HREF="appendix.html#AEN8773"
> I'm now the following notice in the
logs:</A
></DT
><DT
>7.1.4.6. <A
HREF="appendix.html#AEN8789"
>I pointed a subscribing node to a different provider
and it stopped replicating</A
></DT
><DT
>7.1.4.7. <A
HREF="appendix.html#AEN8826"
> I was starting a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
>, and got the
following <SPAN
CLASS="QUOTE"
>"FATAL"</SPAN
> messages in its logs.  What's up??? </A
></DT
><DT
>7.1.4.8. <A
HREF="appendix.html#AEN8867"
> When can I shut down <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes?</A
></DT
><DT
>7.1.4.9. <A
HREF="appendix.html#AEN8905"
> Are there risks to shutting down the slon?  How about
benefits?</A
></DT
><DT
>7.1.4.10. <A
HREF="appendix.html#AEN8914"
> I was trying to subscribe a set involving a multiple GB table, and it failed.</A
></DT
></DL
></DD
><DT
>5. <A
HREF="appendix.html#FAQCONFIGURATION"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Configuration Issues </A
></DT
><DD
><DL
><DT
>7.1.5.1. <A
HREF="appendix.html#AEN8938"
>ps finds passwords on command line</A
></DT
><DT
>7.1.5.2. <A
HREF="appendix.html#AEN8946"
>Table indexes with FQ namespace names

</P><PRE
CLASS="PROGRAMLISTING"
>set add table (set id = 1, origin = 1, id = 27, 
               full qualified name = 'nspace.some_table', 
               key = 'key_on_whatever', 
               comment = 'Table some_table in namespace nspace with a candidate primary key');</PRE
><P></A
></DT
><DT
>7.1.5.3. <A
HREF="appendix.html#AEN8954"
> Replication has fallen behind, and it appears that
the queries to draw data from <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> are taking a long time
to pull just a few
<TT
CLASS="COMMAND"
>SYNC</TT
>s. </A
></DT
><DT
>7.1.5.4. <A
HREF="appendix.html#AEN8970"
> I need to rename a column that is in the
primary key for one of my replicated tables.  That seems pretty
dangerous, doesn't it?  I have to drop the table out of replication
and recreate it, right?</A
></DT
><DT
>7.1.5.5. <A
HREF="appendix.html#AEN8990"
> I had a network <SPAN
CLASS="QUOTE"
>"glitch"</SPAN
> that led to my
using <A
HREF="stmtfailover.html"
>SLONIK FAILOVER</A
> to fail over to an alternate node.
The failure wasn't a disk problem that would corrupt databases; why do
I need to rebuild the failed node from scratch? </A
></DT
><DT
>7.1.5.6. <A
HREF="appendix.html#AEN9010"
> After notification of a subscription on
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>another</I
></SPAN
> node, replication falls over on one of
the subscribers, with the following error message:</A
></DT
><DT
>7.1.5.7. <A
HREF="appendix.html#AEN9029"
>I just used <A
HREF="stmtmoveset.html"
>SLONIK MOVE SET</A
> to move the
origin to a new node.  Unfortunately, some subscribers are still
pointing to the former origin node, so I can't take it out of service
for maintenance without stopping them from getting updates.  What do I
do?  </A
></DT
><DT
>7.1.5.8. <A
HREF="appendix.html#AEN9041"
> After notification of a subscription on
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>another</I
></SPAN
> node, replication falls over, starting
with the following error message:</A
></DT
><DT
>7.1.5.9. <A
HREF="appendix.html#AEN9060"
> Is the ordering of tables in a set significant?</A
></DT
><DT
>7.1.5.10. <A
HREF="appendix.html#AEN9077"
> If you have a <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
> script
something like this, it will hang on you and never complete, because
you can't have <A
HREF="stmtwaitevent.html"
>SLONIK WAIT FOR EVENT</A
> inside a <A
HREF="slonikref.html#TRYBLOCK"
>Section 1.3</A
> block. A <TT
CLASS="COMMAND"
>try</TT
> block is executed
as one transaction, and the event that you are waiting for can never
arrive inside the scope of the transaction.</A
></DT
><DT
>7.1.5.11. <A
HREF="appendix.html#AEN9090"
>Slony-I: cannot add table to currently subscribed set 1</A
></DT
><DT
>7.1.5.12. <A
HREF="appendix.html#AEN9099"
>ERROR: duplicate key violates unique constraint "sl_table-pkey"</A
></DT
><DT
>7.1.5.13. <A
HREF="appendix.html#AEN9108"
> One of my nodes fell over (<A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> / postmaster was
down) and nobody noticed for several days.  Now, when the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> for
that node starts up, it runs for about five minutes, then terminates,
with the error message: <TT
CLASS="COMMAND"
>ERROR: remoteListenThread_%d: timeout
for event selection</TT
> What's wrong, and what do I do? </A
></DT
></DL
></DD
><DT
>6. <A
HREF="appendix.html#FAQPERFORMANCE"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Performance Issues </A
></DT
><DD
><DL
><DT
>7.1.6.1. <A
HREF="appendix.html#AEN9133"
> Replication has been slowing down, I'm seeing
<TT
CLASS="COMMAND"
> FETCH 100 FROM LOG </TT
> queries running for a long
time, <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> is growing, and performance is, well,
generally getting steadily worse. </A
></DT
><DT
>7.1.6.2. <A
HREF="appendix.html#AEN9177"
>After dropping a node, <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
>
aren't getting purged out anymore.</A
></DT
><DT
>7.1.6.3. <A
HREF="appendix.html#AEN9217"
>The <SPAN
CLASS="APPLICATION"
>slon</SPAN
> spent the weekend out of
commission [for some reason], and it's taking a long time to get a
sync through.</A
></DT
><DT
>7.1.6.4. <A
HREF="appendix.html#AEN9241"
> I have submitted a <A
HREF="stmtmoveset.html"
>SLONIK MOVE SET</A
> / <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
> request, and
it seems to be stuck on one of my nodes.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> logs aren't
displaying any errors or warnings </A
></DT
><DT
>7.1.6.5. <A
HREF="appendix.html#AEN9256"
> I'm noticing in the logs that a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> is frequently
switching in and out of <SPAN
CLASS="QUOTE"
>"polling"</SPAN
> mode as it is
frequently reporting <SPAN
CLASS="QUOTE"
>"LISTEN - switch from polling mode to use
LISTEN"</SPAN
> and <SPAN
CLASS="QUOTE"
>"UNLISTEN - switch into polling
mode"</SPAN
>. </A
></DT
></DL
></DD
><DT
>7. <A
HREF="appendix.html#FAQBUGS"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> Bugs in Elder Versions </A
></DT
><DD
><DL
><DT
>7.1.7.1. <A
HREF="appendix.html#AEN9273"
>The <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes servicing my
subscribers are growing to enormous size, challenging system resources
both in terms of swap space as well as moving towards breaking past
the 2GB maximum process size on my system. </A
></DT
><DT
>7.1.7.2. <A
HREF="appendix.html#AEN9313"
> I am trying to replicate
<TT
CLASS="ENVAR"
>UNICODE</TT
> data from <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.0 to <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.1, and
am experiencing problems. </A
></DT
><DT
>7.1.7.3. <A
HREF="appendix.html#AEN9337"
> I am running <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.1 and have a 4+ node setup
where there are two subscription sets, 1 and 2, that do not share any
nodes.  I am discovering that confirmations for set 1 never get to the
nodes subscribing to set 2, and that confirmations for set 2 never get
to nodes subscribing to set 1.  As a result, <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> grow
and grow, and are never purged.  This was reported as
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> <A
HREF="http://gborg.postgresql.org/project/slony1/bugs/bugupdate.php?1485"
TARGET="_top"
>bug 1485 </A
>.</A
></DT
><DT
>7.1.7.4. <A
HREF="appendix.html#AEN9356"
> I am finding some multibyte columns (Unicode, Big5)
are being truncated a bit, clipping off the last character.  Why?</A
></DT
><DT
>7.1.7.5. <A
HREF="appendix.html#AEN9364"
> <A
HREF="http://gborg.postgresql.org/project/slony1/bugs/bugupdate.php?1226"
TARGET="_top"
>Bug #1226 </A
> indicates an error condition that can come up if
you have a replication set that consists solely of sequences. </A
></DT
><DT
>7.1.7.6. <A
HREF="appendix.html#AEN9379"
>I need to drop a table from a replication set</A
></DT
><DT
>7.1.7.7. <A
HREF="appendix.html#AEN9402"
>I need to drop a sequence from a replication set</A
></DT
><DT
>7.1.7.8. <A
HREF="appendix.html#AEN9426"
> I set up my cluster using pgAdminIII, with cluster
name <SPAN
CLASS="QUOTE"
>"MY-CLUSTER"</SPAN
>.  Time has passed, and I tried using
Slonik to make a configuration change, and this is failing with the
following error message:</A
></DT
></DL
></DD
><DT
>8. <A
HREF="appendix.html#FAQOBSOLETE"
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Anachronisms -
Hopefully Obsolete </A
></DT
><DD
><DL
><DT
>7.1.8.1. <A
HREF="appendix.html#AEN9451"
> <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> does not restart after
crash</A
></DT
><DT
>7.1.8.2. <A
HREF="appendix.html#AEN9483"
> I tried the following query which did not work:</A
></DT
><DT
>7.1.8.3. <A
HREF="appendix.html#AEN9511"
> I can do a <TT
CLASS="COMMAND"
>pg_dump</TT
>
and load the data back in much faster than the <TT
CLASS="COMMAND"
>SUBSCRIBE
SET</TT
> runs.  Why is that?  </A
></DT
><DT
>7.1.8.4. <A
HREF="appendix.html#AEN9536"
>Replication Fails - Unique Constraint Violation</A
></DT
><DT
>7.1.8.5. <A
HREF="appendix.html#AEN9573"
>I started doing a backup using
<SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
>, and suddenly Slony
stops</A
></DT
></DL
></DD
><DT
></DT
><DD
><DL
><DT
>7.1.9.1. <A
HREF="appendix.html#AEN9620"
> I was trying to request <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
> or <A
HREF="stmtmoveset.html"
>SLONIK MOVE SET</A
>, and found
messages as follows on one of the subscribers:</A
></DT
><DT
>7.1.9.2. <A
HREF="appendix.html#AEN9650"
> Behaviour - all the subscriber nodes start to fall
behind the origin, and all the logs on the subscriber nodes have the
following error message repeating in them (when I encountered it,
there was a nice long SQL statement above each entry):</A
></DT
><DT
>7.1.9.3. <A
HREF="appendix.html#AEN9673"
> Node #1 was dropped via <A
HREF="stmtdropnode.html"
>SLONIK DROP NODE</A
>, and the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> one of the
other nodes is repeatedly failing with the error message:</A
></DT
><DT
>7.1.9.4. <A
HREF="appendix.html#AEN9698"
> I have a database where we have been encountering
the following error message in our application: </A
></DT
><DT
>7.1.9.5. <A
HREF="appendix.html#AEN9718"
> I tried building <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.1 and got the following
error message:
</P><PRE
CLASS="SCREEN"
>configure: error: Headers for libpqserver are not found in the includeserverdir.
   This is the path to postgres.h. Please specify the includeserverdir with
   --with-pgincludeserverdir=&lt;dir&gt;</PRE
><P></A
></DT
><DT
>7.1.9.6. <A
HREF="appendix.html#AEN9731"
> I'm trying to upgrade to a newer version of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
and am running into a problem with <A
HREF="stmtupdatefunctions.html"
>SLONIK UPDATE FUNCTIONS</A
>.  When I run <A
HREF="stmtupdatefunctions.html"
>SLONIK UPDATE FUNCTIONS</A
>, my
<SPAN
CLASS="APPLICATION"
>postmaster</SPAN
> falls over with a Signal 11.
There aren't any seeming errors in the log files, aside from the
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> logs indicating that, yes indeed, the postmaster fell
over.</A
></DT
><DT
>7.1.9.7. <A
HREF="appendix.html#AEN9801"
>Slonik fails - cannot load <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> library -
<TT
CLASS="COMMAND"
>PGRES_FATAL_ERROR load '$libdir/xxid';</TT
></A
></DT
><DT
>7.1.9.8. <A
HREF="appendix.html#AEN9833"
>I tried creating a CLUSTER NAME with a "-" in it.
That didn't work.</A
></DT
><DT
>7.1.9.9. <A
HREF="appendix.html#AEN9842"
> I have a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 7.2-based system that I
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>really, really</I
></SPAN
> want to use <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to help me
upgrade it to 8.0.  What is involved in getting <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to work for
that?</A
></DT
><DT
>7.1.9.10. <A
HREF="appendix.html#AEN9876"
> I created a <SPAN
CLASS="QUOTE"
>"superuser"</SPAN
> account,
<TT
CLASS="COMMAND"
>slony</TT
>, to run replication activities.  As
suggested, I set it up as a superuser, via the following query: 
<TT
CLASS="COMMAND"
>update pg_shadow set usesuper = 't' where usename in ('slony',
'molly', 'dumpy');</TT
>
(that command also deals with other users I set up to run vacuums and
backups).</A
></DT
><DT
>7.1.9.11. <A
HREF="appendix.html#AEN9897"
>Some nodes start consistently falling behind</A
></DT
></DL
></DD
></DL
><A
NAME="AEN8366"
></A
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQCOMPILING"
></A
>1.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Building and Installing <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8374"
></A
><B
>7.1.1.1. </B
> I am using <SPAN
CLASS="PRODUCTNAME"
> Frotznik Freenix
4.5</SPAN
>, with its <ACRONYM
CLASS="ACRONYM"
>FFPM</ACRONYM
> (Frotznik Freenix
Package Manager) package management system.  It comes with
<ACRONYM
CLASS="ACRONYM"
>FFPM</ACRONYM
> packages for <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 7.4.7, which are what
I am using for my databases, but they don't include <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> in the
packaging.  How do I add <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to this?  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Frotznik Freenix</SPAN
> is new to
me, so it's a bit dangerous to give really hard-and-fast definitive
answers.  </P
><P
> The answers differ somewhat between the various combinations of
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> and <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> versions; the newer versions generally
somewhat easier to cope with than are the older versions.  In general,
it is quite likely that you will need to compile <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> from
sources; depending on versioning of both <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> and <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, you
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>may</I
></SPAN
> also need to compile <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> from scratch.
(Whether you need to <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
> use </I
></SPAN
> the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> compile
is another matter; you probably don't...) </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In these modern days, many people are using systems
like <SPAN
CLASS="APPLICATION"
><A
HREF="http://www.puppetlabs.com/"
TARGET="_top"
>Puppet</A
></SPAN
> where
they expect to be able to get versions of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> and <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
packaged up using their systems' native packaging tools (such as
<SPAN
CLASS="APPLICATION"
>RPM</SPAN
>, with <A
HREF="http://yum.postgresql.org/"
TARGET="_top"
> yum.postgresql.org</A
>,
<SPAN
CLASS="APPLICATION"
>dpkg</SPAN
> - with <A
HREF="http://wiki.postgresql.org/wiki/Apt"
TARGET="_top"
> PostgreSQL packages for
Debian and Ubuntu </A
>).</P
><P
> It is possible that you will be able to find suitable
pre-compiled packages for <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> and <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> for your system, if
you are using a popular Linux distribution, and there is a single
version of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> across your cluster. </P
><P
> If you are using a system distribution that has not attracted
such packaging, or if you are using <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to upgrade between
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> versions, and therefore require it compiled for multiple
versions of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, it is quite likely you will need to compile
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> (and perhaps <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>) yourself.</P
><P
> You will likely find it useful to consult the appropriate
repository above (YUM, for RPM-based systems, and APT, for Debian
derivatives) to obtain configuration to help you build packages
yourself.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In the <SPAN
CLASS="QUOTE"
>"old days"</SPAN
>, the build process was
more arduous than is the case with version 2.0 and above:

<P
></P
></P><UL
><LI
><P
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> version 1.0.5 and earlier required having a
fully configured copy of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> sources available when you compile
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>.</P
><P
> <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>Hopefully</I
></SPAN
> you can make the configuration
this closely match against the configuration in use by the packaged
version of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> by checking the configuration using the command
<TT
CLASS="COMMAND"
> pg_config --configure</TT
>. </P
></LI
><LI
><P
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> version 1.1 simplified this considerably;
it did not require the full copy of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> sources, but could,
instead, refer to the various locations where <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> libraries,
binaries, configuration, and <TT
CLASS="COMMAND"
> #include </TT
> files are
located.  </P
></LI
><LI
><P
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.0 and higher have become much easier to
deal with in that a <SPAN
CLASS="QUOTE"
>"default"</SPAN
> installation includes all
of the <TT
CLASS="COMMAND"
> #include </TT
> files.  </P
><P
> If you are using an earlier version of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, you may find
it necessary to resort to a source installation if the packaged
version did not install the <SPAN
CLASS="QUOTE"
>"server
<TT
CLASS="COMMAND"
>#include</TT
>"</SPAN
> files, which are installed by the
command <TT
CLASS="COMMAND"
> make install-all-headers </TT
>.</P
></LI
></UL
><P>&#13;</P
><P
> In effect, the <SPAN
CLASS="QUOTE"
>"worst case"</SPAN
> scenario takes place
if you are using a version of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> earlier than 1.1 with an
<SPAN
CLASS="QUOTE"
>"elderly"</SPAN
> version of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, in which case you can
expect to need to compile <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> from scratch in order to have
everything that the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> compile needs even though you are using a
<SPAN
CLASS="QUOTE"
>"packaged"</SPAN
> version of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>.</P
><P
> If you are running a recent <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> and a recent <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>,
then the codependencies can be fairly small, and you may not need
extra <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> sources.  These improvements should ease the
production of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> packages so that you might soon even be able to
hope to avoid compiling <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8461"
></A
><B
>7.1.1.2. </B
> Problem building on Fedora/x86-64 </P
><P
> When trying to configure <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> on a Fedora x86-64 system,
where <SPAN
CLASS="APPLICATION"
>yum</SPAN
> was used to install the package
<TT
CLASS="FILENAME"
>postgresql-libs.x86_64</TT
>, the following complaint
comes up:

</P><PRE
CLASS="SCREEN"
>configure: error: Your version of libpq doesn't have PQunescapeBytea
 this means that your version of PostgreSQL is lower than 7.3
 and thus not supported by Slony-I.</PRE
><P></P
><P
> This happened with <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.2.5, which is certainly rather
newer than 7.3. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="APPLICATION"
>configure</SPAN
> is looking for
that symbol by compiling a little program that calls for it, and
checking if the compile succeeds.  On the <TT
CLASS="COMMAND"
>gcc</TT
>
command line it uses <TT
CLASS="COMMAND"
>-lpq</TT
> to search for the
library. </P
><P
> Unfortunately, in this precise case that package is missing a
symlink, from <TT
CLASS="FILENAME"
>/usr/lib64/libpq.so</TT
> to
<TT
CLASS="FILENAME"
>libpq.so.5.0</TT
>; that is why it fails to link to
libpq.  The <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>true</I
></SPAN
> problem is that the compiler
failed to find a library to link to, not that libpq lacked the
function call. </P
><P
> Eventually, this should be addressed by those that manage the
<TT
CLASS="FILENAME"
>postgresql-libs.x86_64</TT
> package. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> While the problem is reported with a particular
system, the complaint about <SPAN
CLASS="QUOTE"
>"version lower than 7.3"</SPAN
> has
been a common one, reported across various sorts of systems. </P
><P
> Note that this same symptom has been a common indicatior for
various similar classes of system configuration problems.  Bad
symlinks, bad permissions, bad behaviour on the part of your C
compiler, all may potentially lead to this same error message. </P
><P
> Thus, if you see this error, you need to look in the log file
that is generated, <TT
CLASS="FILENAME"
>config.log</TT
>.  Search down to
near the end, and see what the <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>actual</I
></SPAN
> complaint
was.  That will be helpful in tracking down the true root cause of the
problem.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8489"
></A
><B
>7.1.1.3. </B
> I found conflicting types for <TT
CLASS="ENVAR"
>yyleng</TT
>
between <TT
CLASS="FILENAME"
>parser.c</TT
> and <TT
CLASS="FILENAME"
>scan.c</TT
>.
In one case, it used type <TT
CLASS="TYPE"
>int</TT
>, conflicting with
<TT
CLASS="TYPE"
>yy_size_t</TT
>.  What shall I do?</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This has been observed on <SPAN
CLASS="APPLICATION"
>MacOS</SPAN
>,
where <SPAN
CLASS="APPLICATION"
>flex</SPAN
> (which generates
<TT
CLASS="FILENAME"
>scan.c</TT
>) and <SPAN
CLASS="APPLICATION"
>bison</SPAN
>
(which generates <TT
CLASS="FILENAME"
>parser.c</TT
>) diverged in their
handling of this variable. </P
><P
></P
><UL
><LI
><P
> You might might <SPAN
CLASS="QUOTE"
>"hack"</SPAN
> <TT
CLASS="FILENAME"
>scan.c</TT
> by hand to use the matching type. </P
></LI
><LI
><P
> You might select different versions of <SPAN
CLASS="APPLICATION"
>bison</SPAN
> or <SPAN
CLASS="APPLICATION"
>flex</SPAN
> so as to get versions whose data types match. </P
></LI
><LI
><P
> Note that you may have multiple versions of <SPAN
CLASS="APPLICATION"
>bison</SPAN
> or <SPAN
CLASS="APPLICATION"
>flex</SPAN
> around, and might need to modify <TT
CLASS="ENVAR"
>PATH</TT
> in order to select the appropriate one.</P
></LI
></UL
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQHOWTO"
></A
>2.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: How Do I? </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8521"
></A
><B
>7.1.2.1. </B
> I need to dump a database
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>without</I
></SPAN
> getting <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> configuration
(<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>e.g.</I
></SPAN
> - triggers, functions, and such). </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Up to version 1.2, this is fairly nontrivial,
requiring careful choice of nodes, and some moderately heavy
<SPAN
CLASS="QUOTE"
>"procedure"</SPAN
>.  One methodology has been as follows:</P
><P
></P
><UL
><LI
><P
> First, dump the schema from the node that has the
<SPAN
CLASS="QUOTE"
>"master"</SPAN
> role.  That is the only place, pre-2.0, where
you can readily dump the schema using
<SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> and have a consistent schema.  You
may use the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> tool <A
HREF="additionalutils.html#EXTRACTSCHEMA"
>Section 6.1.6</A
> to do
this. </P
></LI
><LI
><P
> Take the resulting schema, which will <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not</I
></SPAN
>
include the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>-specific bits, and split it into two pieces:</P
><P
></P
><UL
><LI
><P
> Firstly, the portion comprising all of the creations
of tables in the schema. </P
></LI
><LI
><P
> Secondly, the portion consisting of creations of
indices, constraints, and triggers. </P
></LI
></UL
></LI
><LI
><P
> Pull a data dump, using <TT
CLASS="COMMAND"
>pg_dump --data-only</TT
>, of some node of your choice.  It doesn't need to be for the <SPAN
CLASS="QUOTE"
>"master"</SPAN
> node.  This dump will include the contents of the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>-specific tables; you can discard that, or ignore it.  Since the schema dump didn't contain table definitions for the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> tables, they won't be loaded. </P
></LI
><LI
><P
> Finally, load the three components in proper order: </P
><P
></P
><UL
><LI
><P
> Schema (tables) </P
></LI
><LI
><P
> Data dump </P
></LI
><LI
><P
> Remainder of the schema </P
></LI
></UL
></LI
></UL
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 2.0, the answer becomes simpler: Just take
a <TT
CLASS="COMMAND"
>pg_dump --exclude-schema=_Cluster</TT
> against
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>any</I
></SPAN
> node.  In 2.0, the schemas are no longer
<SPAN
CLASS="QUOTE"
>"clobbered"</SPAN
> on subscribers, so a straight
<SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> will do what you want.</P
><P
> There is a small issue that will remain; the log triggers that
are added to replicated tables will still be included in the dump,
although the functions that they refer to are in the excluded schema.
You should be prepared to find that those triggers will fail to load.
You might use <TT
CLASS="COMMAND"
>grep -v</TT
> on the dump to filter out the
triggers, should that prove to be a problem.  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8570"
></A
><B
>7.1.2.2. </B
> How should I run <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> A <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> process is required for each database that
participates in replication.  There are a variety of ways of managing
these processes, none strictly <SPAN
CLASS="QUOTE"
>"the best."</SPAN
> An
administrator may find one or another of these to be
preferable.</P
><P
></P
><UL
><LI
><P
> <A
HREF="additionalutils.html#SLONWATCHDOG"
> Perl Watchdog</A
>, a
script which monitors a node and restarts <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> for that node if it
sees no activity. </P
></LI
><LI
><P
> <A
HREF="additionalutils.html#STARTSLON"
>start_slon.sh</A
>,
written with a view to managing the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> configuration via the
<A
HREF="runtime-config.html"
> slon runtime configuraiton</A
>.</P
></LI
><LI
><P
> <A
HREF="additionalutils.html#LAUNCHCLUSTERS"
>launch_clusters.sh</A
>, which can start up
multiple <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes.  This does a one-time startup of missing
<A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes, so should be run periodically using a service such
as cron. </P
></LI
><LI
><P
> <A
HREF="additionalutils.html#UPSTARTSCRIPT"
> Upstart script </A
>
may be used to start a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> process when the system boots, suitable
for systems that use Upstart for managing system
services. </P
></LI
><LI
><P
> <A
HREF="additionalutils.html#BSD-PORTS-PROFILE"
> BSD Ports Profile</A
> provides Apache-style profiles, suitable for systems managing
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> using FreeBSD Ports. </P
></LI
><LI
><P
> <A
HREF="startingstopping.html#SLONONWINDOWS"
> Slon on Windows</A
> describes the use of <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> with the Windows
<SPAN
CLASS="QUOTE"
>"service"</SPAN
> concept.</P
></LI
><LI
><P
> Not provided, but a straightforward task, would be to
create an <SPAN
CLASS="QUOTE"
>"init"</SPAN
> script suitable for Unix systems that
use SysV <SPAN
CLASS="APPLICATION"
>init</SPAN
>. </P
></LI
></UL
><P
> A single answer will not fit all, as different operating
systems have different mechanisms for dealing with persistent
processes, and as administrators may wish to have one, or several
<A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes running on a particular server. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8612"
></A
><B
>7.1.2.3. </B
> I'd like to renumber the node numbers in my cluster.
How can I renumber nodes? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The first answer is <SPAN
CLASS="QUOTE"
>"you can't do that"</SPAN
> -
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> node numbers are quite <SPAN
CLASS="QUOTE"
>"immutable."</SPAN
> Node numbers
are deeply woven into the fibres of the schema, by virtue of being
written into virtually every table in the system, but much more
importantly by virtue of being used as the basis for event
propagation.  The only time that it might be <SPAN
CLASS="QUOTE"
>"OK"</SPAN
> to
modify a node number is at some time where we know that it is not in
use, and we would need to do updates against each node in the cluster
in an organized fashion.</P
><P
> To do this in an automated fashion seems like a
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>huge</I
></SPAN
> challenge, as it changes the structure of
the very event propagation system that already needs to be working in
order for such a change to propagate.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If it is <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>enormously necessary</I
></SPAN
> to
renumber nodes, this might be accomplished by dropping and re-adding
nodes to get rid of the node formerly using the node ID that needs to
be held by another node.</P
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQIMPOSSIBILITIES"
></A
>3.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Impossible Things People Try </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8629"
></A
><B
>7.1.3.1. </B
> Can I use <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to replicate changes back and
forth on my database between my two offices? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> At one level, it is <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>theoretically
possible</I
></SPAN
> to do something like that, if you design your
application so that each office has its own distinct set of tables,
and you then have some system for consolidating the data to give them
some common view.  However, this requires a great deal of design work
to create an application that performs this consolidation. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In practice, the term for that is <SPAN
CLASS="QUOTE"
>"multimaster
replication,"</SPAN
> and <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> does not support <SPAN
CLASS="QUOTE"
>"multimaster
replication."</SPAN
> </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8641"
></A
><B
>7.1.3.2. </B
> I want to replicate all of the databases for a
shared-database system I am managing.  There are multiple databases,
being used by my customers.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> cannot be directly used for this, as it
expects to capture changes from <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>a database</I
></SPAN
>, not a
set of <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>several databases</I
></SPAN
>.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> For this purpose, something like <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> PITR (Point
In Time Recovery) is likely to be much more suitable.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
requires a slon process (and multiple connections) for each
identifiable database, and if you have a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> cluster hosting 50
or 100 databases, this will require hundreds of database connections.
Typically, in <SPAN
CLASS="QUOTE"
>"shared hosting"</SPAN
> situations, DML is being
managed by customers, who can change anything they like whenever
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>they</I
></SPAN
> want.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> does not work out well when
not used in a disciplined manner.  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8657"
></A
><B
>7.1.3.3. </B
> I want to be able to make DDL changes, and have them replicated automatically. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> requires that <A
HREF="ddlchanges.html"
>Section 3.3</A
> be planned for explicitly and carefully.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> captures changes using triggers, and <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> does not provide a way to use triggers to capture DDL changes.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
> There has been quite a bit of discussion, off and on,
about how <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> might capture DDL changes in a way that would
make triggers useful; nothing concrete has yet emerged despite several
years of discussion. </P
><P
> The EVENT TRIGGERs added in <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 9.3 are drawing steps
closer on this, but a usable solution has not yet emerged.  Perhaps in
9.4...</P
></BLOCKQUOTE
></DIV
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8671"
></A
><B
>7.1.3.4. </B
> I want to split my cluster into disjoint partitions
that are not aware of one another.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> keeps generating <A
HREF="listenpaths.html"
>Section 4.2</A
> that link those partitions together. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The notion that all nodes are aware of one another is
deeply imbedded in the design of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>.  For instance, its handling
of cleanup of obsolete data depends on being aware of whether any of
the nodes are behind, and thus might still depend on older data.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8679"
></A
><B
>7.1.3.5. </B
> I want to change some of my node numbers.  How do I <SPAN
CLASS="QUOTE"
>"rename"</SPAN
> a node to have a different node number? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You don't.  The node number is used to coordinate inter-node communications, and changing the node ID number <SPAN
CLASS="QUOTE"
>"on the fly"</SPAN
> would make it essentially impossible to keep node configuration coordinated.   </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8686"
></A
><B
>7.1.3.6. </B
> My application uses OID attributes; is it possible to replicate tables like this? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> It is worth noting that oids, as a regular table
attribute, have been deprecated since <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> version 8.1, back in
2005.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> has <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>never</I
></SPAN
> collected oids to
replicate them, and, with that functionality being deprecated, the
developers do not intend to add this functionality. </P
><P
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> implemented oids as a way to link its internal
system tables together; to use them with application tables is
considered <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>poor practice</I
></SPAN
>, and it is recommended
that you use sequences to populate your own ID column on application
tables.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Of course, nothing prevents you from creating a table
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>without</I
></SPAN
> oids, and then add in your own
application column called <TT
CLASS="ENVAR"
>oid</TT
>, preferably with type
information <TT
CLASS="COMMAND"
>SERIAL NOT NULL UNIQUE</TT
>, which
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>can</I
></SPAN
> be replicated, and which is likely to be
suitable as a candidate primary key for the table. </P
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQCONNECTIONS"
></A
>4.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Connection Issues </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8706"
></A
><B
>7.1.4.1. </B
>I looked for the <TT
CLASS="ENVAR"
>_clustername</TT
> namespace, and
it wasn't there.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If the DSNs are wrong, then <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
>
instances can't connect to the nodes.</P
><P
>This will generally lead to nodes remaining entirely untouched.</P
><P
>Recheck the connection configuration.  By the way, since <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> links to libpq, you could have password information
stored in <TT
CLASS="FILENAME"
> $HOME/.pgpass</TT
>, partially filling in
right/wrong authentication information there.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8717"
></A
><B
>7.1.4.2. </B
> I'm trying to get a slave subscribed, and get the
following messages in the logs:

</P><PRE
CLASS="SCREEN"
>DEBUG1 copy_set 1
DEBUG1 remoteWorkerThread_1: connected to provider DB
WARN	remoteWorkerThread_1: transactions earlier than XID 127314958 are still in progress
WARN	remoteWorkerThread_1: data copy for set 1 failed - sleep 60 seconds</PRE
><P></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> There is evidently some reasonably old outstanding
transaction blocking <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> from processing the sync.  You might
want to take a look at pg_locks to see what's up:</P
><PRE
CLASS="SCREEN"
>sampledb=# select * from pg_locks where transaction is not null order by transaction;
 relation | database | transaction |  pid    |     mode      | granted 
----------+----------+-------------+---------+---------------+---------
          |          |   127314921 | 2605100 | ExclusiveLock | t
          |          |   127326504 | 5660904 | ExclusiveLock | t
(2 rows)</PRE
><P
>See?  127314921 is indeed older than 127314958, and it's still
running.  While the situation may be undesirable, there is no error in
the behaviour of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>.</P
><P
> A long running accounting report, a runaway search query, a
<SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
>, all can open up transactions that
may run for substantial periods of time.  Until they complete, or are
interrupted, you will continue to see the message <SPAN
CLASS="QUOTE"
>" data copy
for set 1 failed - sleep 60 seconds "</SPAN
>.</P
><P
>By the way, if there is more than one database on the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
cluster, and activity is taking place on the OTHER database, that will
lead to there being <SPAN
CLASS="QUOTE"
>"transactions earlier than XID
whatever"</SPAN
> being found to be still in progress.  The fact that
it's a separate database on the cluster is irrelevant; <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> will
wait until those old transactions terminate.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8734"
></A
><B
>7.1.4.3. </B
>Same as the above.  What I forgot to mention, as well,
was that I was trying to add <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>TWO</I
></SPAN
> subscribers,
concurrently.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> That doesn't work out happily: <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> can't work on
the <TT
CLASS="COMMAND"
>COPY</TT
> commands concurrently.  See
<TT
CLASS="FILENAME"
>src/slon/remote_worker.c</TT
>, function
<CODE
CLASS="FUNCTION"
>copy_set()</CODE
></P
><PRE
CLASS="SCREEN"
>$ ps -aef | egrep '[2]605100'
postgres 2605100  205018	0 18:53:43  pts/3  3:13 postgres: postgres sampledb localhost COPY </PRE
><P
>This happens to be a <TT
CLASS="COMMAND"
>COPY</TT
> transaction
involved in setting up the subscription for one of the nodes.  All is
well; the system is busy setting up the first subscriber; it won't
start on the second one until the first one has completed subscribing.
That represents one possible cause.</P
><P
>This has the (perhaps unfortunate) implication that you cannot
populate two slaves concurrently from a single provider.  You have to
subscribe one to the set, and only once it has completed setting up
the subscription (copying table contents and such) can the second
subscriber start setting up the subscription.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8748"
></A
><B
>7.1.4.4. </B
> We got bitten by
something we didn't foresee when completely uninstalling a slony
replication cluster from the master and slave...</P
><DIV
CLASS="WARNING"
><P
></P
><TABLE
CLASS="WARNING"
BORDER="1"
WIDTH="100%"
><TR
><TD
ALIGN="CENTER"
><B
>Warning</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
><SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>MAKE SURE YOU STOP YOUR APPLICATION RUNNING
AGAINST YOUR MASTER DATABASE WHEN REMOVING THE WHOLE SLONY
CLUSTER</I
></SPAN
>, or at least re-cycle all your open connections
after the event!  </P
></TD
></TR
></TABLE
></DIV
><P
> The connections <SPAN
CLASS="QUOTE"
>"remember"</SPAN
> or refer to OIDs which
are removed by the uninstall node script. And you will get lots of
errors as a result...</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> There are two notable areas of
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> that cache query plans and OIDs:</P
><P
></P
><UL
><LI
><P
> Prepared statements</P
></LI
><LI
><P
> pl/pgSQL functions</P
></LI
></UL
><P
> The problem isn't particularly a <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> one; it would occur
any time such significant changes are made to the database schema.  It
shouldn't be expected to lead to data loss, but you'll see a wide
range of OID-related errors.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The problem occurs when you are using some sort of
<SPAN
CLASS="QUOTE"
>"connection pool"</SPAN
> that keeps recycling old connections.
If you restart the application after this, the new connections will
create <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>new</I
></SPAN
> query plans, and the errors will go
away.  If your connection pool drops the connections, and creates new
ones, the new ones will have <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>new</I
></SPAN
> query plans, and
the errors will go away. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In our code we drop the connection on any error we
cannot map to an expected condition. This would eventually recycle all
connections on such unexpected problems after just one error per
connection.  Of course if the error surfaces as a constraint violation
which is a recognized condition, this won't help either, and if the
problem is persistent, the connections will keep recycling which will
drop the effect of the pooling, in the latter case the pooling code
could also announce an admin to take a look...  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8773"
></A
><B
>7.1.4.5. </B
> I'm now the following notice in the
logs:</P
><PRE
CLASS="SCREEN"
>NOTICE:  Slony-I: log switch to sl_log_2 still in progress - sl_log_1 not truncated</PRE
><P
> Both <TT
CLASS="ENVAR"
>sl_log_1</TT
> and <TT
CLASS="ENVAR"
>sl_log_2</TT
> are
continuing to grow, and <TT
CLASS="ENVAR"
>sl_log_1</TT
> is never getting
truncated.  What's wrong? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Observe that it is indicated as a
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>NOTICE</I
></SPAN
>, not as an <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ERROR</I
></SPAN
>, so
this is an expected sort of behaviour.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This may be symptomatic of the same issue as above with
dropping replication: if there are still old connections lingering
that are using old query plans that reference the old stored
functions, resulting in the inserts to <TT
CLASS="ENVAR"
>sl_log_1</TT
> </P
><P
> Closing those connections and opening new ones will resolve the
issue. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8789"
></A
><B
>7.1.4.6. </B
>I pointed a subscribing node to a different provider
and it stopped replicating</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
>We noticed this happening when we wanted to re-initialize a node,
where we had configuration thus:

<P
></P
></P><UL
><LI
><P
> Node 1 - provider</P
></LI
><LI
><P
> Node 2 - subscriber to node 1 - the node we're reinitializing</P
></LI
><LI
><P
> Node 3 - subscriber to node 2 - node that should keep replicating</P
></LI
></UL
><P></P
><P
>The subscription for node 3 was changed to have node 1 as
provider, and we did <A
HREF="stmtdropset.html"
>SLONIK DROP SET</A
> /<A
HREF="stmtsubscribeset.html"
>SLONIK SUBSCRIBE SET</A
> for node 2 to get it repopulating.</P
><P
>Unfortunately, replication suddenly stopped to node 3.</P
><P
>The problem was that there was not a suitable set of
<SPAN
CLASS="QUOTE"
>"listener paths"</SPAN
> in <A
HREF="table.sl-listen.html"
>sl_listen</A
> to
allow the events from node 1 to propagate to node 3.  The events were
going through node 2, and blocking behind the <A
HREF="stmtsubscribeset.html"
>SLONIK SUBSCRIBE SET</A
> event that node 2 was working on.</P
><P
>The following slonik script dropped out the listen paths where
node 3 had to go through node 2, and added in direct listens between
nodes 1 and 3.

</P><PRE
CLASS="PROGRAMLISTING"
>cluster name = oxrslive;
 node 1 admin conninfo='host=32.85.68.220 dbname=oxrslive user=postgres port=5432';
 node 2 admin conninfo='host=32.85.68.216 dbname=oxrslive user=postgres port=5432';
 node 3 admin conninfo='host=32.85.68.244 dbname=oxrslive user=postgres port=5432';
 node 4 admin conninfo='host=10.28.103.132 dbname=oxrslive user=postgres port=5432';
try {
  store listen (origin = 1, receiver = 3, provider = 1);
  store listen (origin = 3, receiver = 1, provider = 3);
  drop listen (origin = 1, receiver = 3, provider = 2);
  drop listen (origin = 3, receiver = 1, provider = 2);
}</PRE
><P></P
><P
>Immediately after this script was run, <TT
CLASS="COMMAND"
>SYNC</TT
>
events started propagating again to node 3.

This points out two principles:
<P
></P
></P><UL
><LI
><P
> If you have multiple nodes, and cascaded subscribers,
you need to be quite careful in populating the <A
HREF="stmtstorelisten.html"
>SLONIK STORE LISTEN</A
> entries, and in modifying them if the
structure of the replication <SPAN
CLASS="QUOTE"
>"tree"</SPAN
>
changes.</P
></LI
><LI
><P
> Version 1.1 provides better tools to help manage
this, and later versions of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>hopefully</I
></SPAN
>
populate the listener table automatically <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>and
correctly</I
></SPAN
> such that you should not encounter this
problem. </P
></LI
></UL
><P></P
><P
>The issues of <SPAN
CLASS="QUOTE"
>"listener paths"</SPAN
> are discussed
further at <A
HREF="listenpaths.html"
>Section 4.2</A
> </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8826"
></A
><B
>7.1.4.7. </B
> I was starting a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
>, and got the
following <SPAN
CLASS="QUOTE"
>"FATAL"</SPAN
> messages in its logs.  What's up??? </P
><PRE
CLASS="SCREEN"
>2006-03-29 16:01:34 UTC CONFIG main: slon version 1.2.0 starting up
2006-03-29 16:01:34 UTC DEBUG2 slon: watchdog process started
2006-03-29 16:01:34 UTC DEBUG2 slon: watchdog ready - pid = 28326
2006-03-29 16:01:34 UTC DEBUG2 slon: worker process created - pid = 28327
2006-03-29 16:01:34 UTC CONFIG main: local node id = 1
2006-03-29 16:01:34 UTC DEBUG2 main: main process started
2006-03-29 16:01:34 UTC CONFIG main: launching sched_start_mainloop
2006-03-29 16:01:34 UTC CONFIG main: loading current cluster configuration
2006-03-29 16:01:34 UTC CONFIG storeSet: set_id=1 set_origin=1 set_comment='test set'
2006-03-29 16:01:34 UTC DEBUG2 sched_wakeup_node(): no_id=1 (0 threads + worker signaled)
2006-03-29 16:01:34 UTC DEBUG2 main: last local event sequence = 7
2006-03-29 16:01:34 UTC CONFIG main: configuration complete - starting threads
2006-03-29 16:01:34 UTC DEBUG1 localListenThread: thread starts
2006-03-29 16:01:34 UTC FATAL  localListenThread: "select "_test1538".cleanupNodelock(); insert into "_test1538".sl_nodelock values (    1, 0, "pg_catalog".pg_backend_pid()); " - ERROR:  duplicate key violates unique constraint "sl_nodelock-pkey"

2006-03-29 16:01:34 UTC FATAL  Do you already have a slon running against this node?
2006-03-29 16:01:34 UTC FATAL  Or perhaps a residual idle backend connection from a dead slon?</PRE
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The table <TT
CLASS="ENVAR"
>sl_nodelock</TT
> is used as an
<SPAN
CLASS="QUOTE"
>"interlock"</SPAN
> to prevent two <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes from trying
to manage the same node at the same time.  The <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> tries inserting
a record into the table; it can only succeed if it is the only node
manager. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This error message is typically a sign that you have
started up a second <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> process for a given node.  The <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> asks
the obvious question: <SPAN
CLASS="QUOTE"
>"Do you already have a slon running
against this node?"</SPAN
> </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Supposing you experience some sort of network outage,
the connection between <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> and database may fail, and the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
>
may figure this out long before the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> instance it was
connected to does.  The result is that there will be some number of
idle connections left on the database server, which won't be closed
out until TCP/IP timeouts complete, which seems to normally take about
two hours.  For that two hour period, the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> will try to connect,
over and over, and will get the above fatal message, over and
over. </P
><P
> An administrator may clean this out by logging onto the server
and issuing <TT
CLASS="COMMAND"
>kill -2</TT
> to any of the offending
connections.  Unfortunately, since the problem took place within the
networking layer, neither <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> nor <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> have a direct way of
detecting this. </P
><P
> You can <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>mostly</I
></SPAN
> avoid this by making sure
that <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes always run somewhere nearby the server that
each one manages.  If the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> runs on the same server as the
database it manages, any <SPAN
CLASS="QUOTE"
>"networking failure"</SPAN
> that could
interrupt local connections would be likely to be serious enough to
threaten the entire server.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> It is likely that the <SPAN
CLASS="QUOTE"
>"several hours"</SPAN
> TCP
timeout is rather longer than it should be in these days where people
expect their servers to be pretty synchronously connected.
Configuring the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> to use much shorter timeouts is likely a
wise idea.  The relevant <TT
CLASS="FILENAME"
>postgresql.conf</TT
>
parameters are <TT
CLASS="ENVAR"
>tcp_keepalives_idle</TT
>,
<TT
CLASS="ENVAR"
>tcp_keepalives_interval</TT
>, and
<TT
CLASS="ENVAR"
>tcp_keepalives_count</TT
>.  See <TT
CLASS="COMMAND"
>man 7 tcp</TT
>
for more details.  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8867"
></A
><B
>7.1.4.8. </B
> When can I shut down <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes?</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Generally, when things are running properly, it's no
big deal to shut down a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> process.  Each one is
<SPAN
CLASS="QUOTE"
>"merely"</SPAN
> a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> client, managing one node, which
spawns threads to manage receiving events from other nodes.  </P
><P
>The <SPAN
CLASS="QUOTE"
>"event listening"</SPAN
> threads are no big deal; they
are doing nothing fancier than periodically checking remote nodes to
see if they have work to be done on this node.  If you kill off the
<A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> these threads will be closed, which should have little or no
impact on much of anything.  Events generated while the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> is
down will be picked up when it is restarted.</P
><P
> The <SPAN
CLASS="QUOTE"
>"node managing"</SPAN
> thread is a bit more
interesting; most of the time, you can expect, on a subscriber, for
this thread to be processing <TT
CLASS="COMMAND"
>SYNC</TT
> events.  If you
shut off the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> during an event, the transaction
will fail, and be rolled back, so that when the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> restarts, it
will have to go back and reprocess the event.</P
><P
> The only situation where this will cause
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>particular</I
></SPAN
> <SPAN
CLASS="QUOTE"
>"heartburn"</SPAN
> is if the
event being processed was one which takes a long time to process, the
worst case being where <TT
CLASS="COMMAND"
>COPY_SET</TT
> is doing initial
processing of a large replication set. </P
><P
> The other thing that <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>might</I
></SPAN
> cause trouble
is if the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> runs fairly distant from nodes that it connects to;
you could discover that database connections are left <TT
CLASS="COMMAND"
>idle in
transaction</TT
>.  This would normally only occur if the network
connection is destroyed without either <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> or database being made
aware of it.  In that case, you may discover that
<SPAN
CLASS="QUOTE"
>"zombied"</SPAN
> connections are left around for as long as two
hours if you don't go in by hand and kill off the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> backends.
See the <A
HREF="appendix.html#MULTIPLESLONCONNECTIONS"
>Multiple Slon
Connections</A
> entry for more details.</P
><P
> There is one other case that could cause trouble; when the
<A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> managing the origin node is not running, no
<TT
CLASS="COMMAND"
>SYNC</TT
> events run against that node.  If the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
>
stays down for an extended period of time, and something like <A
HREF="additionalutils.html#GENSYNC"
>Section 6.1.12</A
> isn't running, you could be left with <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>one
big <TT
CLASS="COMMAND"
>SYNC</TT
></I
></SPAN
> to process when it comes back
up.  But that should only be a concern if that <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> is down for an
extended period of time; shutting it down for a few seconds shouldn't
cause any great problem. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8905"
></A
><B
>7.1.4.9. </B
> Are there risks to shutting down the slon?  How about
benefits?</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In short, if you don't have something like an 18 hour
<TT
CLASS="COMMAND"
>COPY_SET</TT
> under way, it's normally not at all a big
deal to take a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> down for a little while, or perhaps even cycle
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>all</I
></SPAN
> the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8914"
></A
><B
>7.1.4.10. </B
> I was trying to subscribe a set involving a multiple GB table, and it failed.</P
><PRE
CLASS="SCREEN"
>Jul 31 22:52:53 dbms TICKER[70295]: [153-1] CONFIG remoteWorkerThread_3: copy table "public"."images"
Jul 31 22:52:53 dbms TICKER[70295]: [154-1] CONFIG remoteWorkerThread_3: Begin COPY of table "public"."images"
Jul 31 22:54:24 dbms TICKER[70295]: [155-1] ERROR  remoteWorkerThread_3: PGgetCopyData() server closed the connection unexpectedly
Jul 31 22:54:24 dbms TICKER[70295]: [155-2]     This probably means the server terminated abnormally
Jul 31 22:54:24 dbms TICKER[70295]: [155-3]     before or while processing the request.
Jul 31 22:54:24 dbms TICKER[70295]: [156-1] WARN   remoteWorkerThread_3: data copy for set 1 failed 1 times - sleep 15 seconds</PRE
><P
> Oh, by the way, I'm using SSL-based <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> conenctions. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> A further examination of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> logs indicated errors of the form: </P
><PRE
CLASS="SCREEN"
>Jul 31 23:00:00 tickerforum postgres[27093]: [9593-2] STATEMENT:  copy "public"."images"
("post_ordinal","ordinal","caption","image","login","file_type","thumb","thumb_width","thumb_height","hidden") to stdout;
Jul 31 23:00:00 tickerforum postgres[27093]: [9594-1] LOG:  SSL error: internal error
Jul 31 23:00:00 tickerforum postgres[27093]: [9594-2] STATEMENT:  copy "public"."images" ("post_ordinal","ordinal","caption","image","login","file_type","thumb","thumb_width","thumb_height","hidden") to stdout;
Jul 31 23:00:01 tickerforum postgres[27093]: [9595-1] LOG:  SSL error: internal error</PRE
><P
> This demonstrates a problem with <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> handling of
SSL connections, which is <SPAN
CLASS="QUOTE"
>"out of scope"</SPAN
> for <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
proper (<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>e.g.</I
></SPAN
> - there's no <SPAN
CLASS="QUOTE"
>"there"</SPAN
>
inside <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> for us to try to fix).  </P
><P
> The resolution to the underlying problem will presumably be
handled upstream in the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> project; the workaround is to, at
least for the initial <TT
CLASS="COMMAND"
>SUBSCRIBE SET</TT
> event, switch
to a non-SSL <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> connection.  </P
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQCONFIGURATION"
></A
>5.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Configuration Issues </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8938"
></A
><B
>7.1.5.1. </B
>ps finds passwords on command line</P
><P
> If I run a <TT
CLASS="COMMAND"
>ps</TT
> command, I, and everyone else,
can see passwords on the command line.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
>Take the passwords out of the Slony configuration, and
put them into <TT
CLASS="FILENAME"
>$(HOME)/.pgpass.</TT
></P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8946"
></A
><B
>7.1.5.2. </B
>Table indexes with FQ namespace names

</P><PRE
CLASS="PROGRAMLISTING"
>set add table (set id = 1, origin = 1, id = 27, 
               full qualified name = 'nspace.some_table', 
               key = 'key_on_whatever', 
               comment = 'Table some_table in namespace nspace with a candidate primary key');</PRE
><P></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If you have <TT
CLASS="COMMAND"
> key =
'nspace.key_on_whatever'</TT
> the request will
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>FAIL</I
></SPAN
>.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8954"
></A
><B
>7.1.5.3. </B
> Replication has fallen behind, and it appears that
the queries to draw data from <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> are taking a long time
to pull just a few
<TT
CLASS="COMMAND"
>SYNC</TT
>s. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Until version 1.1.1, there was only one index on
<A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
>, and if there were multiple replication sets, some
of the columns on the index would not provide meaningful selectivity.
If there is no index on column <CODE
CLASS="FUNCTION"
> log_xid</CODE
>, consider
adding it.  See <TT
CLASS="FILENAME"
>slony1_base.sql</TT
> for an example of
how to create the index.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> That's not quite the end of the story; a critical query
had the potential to scan the entirety of these log tables even in
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 2.1.  You generally want to be on the latest version of
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> as there have been efficiency improvements, and in this area,
pretty substantial improvements.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8970"
></A
><B
>7.1.5.4. </B
> I need to rename a column that is in the
primary key for one of my replicated tables.  That seems pretty
dangerous, doesn't it?  I have to drop the table out of replication
and recreate it, right?</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Actually, this is a scenario which works out remarkably
cleanly.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> does indeed make intense use of the primary key
columns, but actually does so in a manner that allows this sort of
change to be made very nearly transparently.</P
><P
> Suppose you revise a column name, as with the SQL DDL <TT
CLASS="COMMAND"
>alter table accounts alter column aid rename to cid; </TT
> This
revises the names of the columns in the table; it
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>simultaneously</I
></SPAN
> renames the names of the columns
in the primary key index.  The result is that the normal course of
things is that altering a column name affects both aspects
simultaneously on a given node.</P
><P
> The <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ideal</I
></SPAN
> and proper handling of this
change would involve using <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
> to deploy
the alteration, which ensures it is applied at exactly the right point
in the transaction stream on each node.</P
><P
> Interestingly, that isn't forcibly necessary.  As long as the
alteration is applied on the replication set's origin before
application on subscribers, things won't break irrepairably.  Some
<TT
CLASS="COMMAND"
>SYNC</TT
> events that do not include changes to the
altered table can make it through without any difficulty...  At the
point that the first update to the table is drawn in by a subscriber,
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>that</I
></SPAN
> is the point at which
<TT
CLASS="COMMAND"
>SYNC</TT
> events will start to fail, as the provider
will indicate the <SPAN
CLASS="QUOTE"
>"new"</SPAN
> set of columns whilst the
subscriber still has the <SPAN
CLASS="QUOTE"
>"old"</SPAN
> ones.  If you then apply
the alteration to the subscriber, it can retry the
<TT
CLASS="COMMAND"
>SYNC</TT
>, at which point it will, finding the
<SPAN
CLASS="QUOTE"
>"new"</SPAN
> column names, work just fine.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN8990"
></A
><B
>7.1.5.5. </B
> I had a network <SPAN
CLASS="QUOTE"
>"glitch"</SPAN
> that led to my
using <A
HREF="stmtfailover.html"
>SLONIK FAILOVER</A
> to fail over to an alternate node.
The failure wasn't a disk problem that would corrupt databases; why do
I need to rebuild the failed node from scratch? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The action of <A
HREF="stmtfailover.html"
>SLONIK FAILOVER</A
> is to
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>abandon</I
></SPAN
> the failed node so that no more <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
activity goes to or from that node.  As soon as that takes place, the
failed node will progressively fall further and further out of sync.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>big</I
></SPAN
> problem with trying to
recover the failed node is that it may contain updates that never made
it out of the origin.  If they get retried, on the new origin, you may
find that you have conflicting updates.  In any case, you do have a
sort of <SPAN
CLASS="QUOTE"
>"logical"</SPAN
> corruption of the data even if there
never was a disk failure making it <SPAN
CLASS="QUOTE"
>"physical."</SPAN
></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> As discusssed in <A
HREF="failover.html"
>Section 3.4</A
>, using <A
HREF="stmtfailover.html"
>SLONIK FAILOVER</A
> should be considered a <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>last
resort</I
></SPAN
> as it implies that you are abandoning the origin
node as being corrupted.  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9010"
></A
><B
>7.1.5.6. </B
> After notification of a subscription on
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>another</I
></SPAN
> node, replication falls over on one of
the subscribers, with the following error message:</P
><PRE
CLASS="SCREEN"
>ERROR  remoteWorkerThread_1: "begin transaction; set transaction isolation level serializable; lock table "_livesystem".sl_config_lock; select "_livesystem".enableSubscription(25506, 1, 501); notify "_livesystem_Event"; notify "_livesystem_Confirm"; insert into "_livesystem".sl_event     (ev_origin, ev_seqno, ev_timestamp,      ev_minxid, ev_maxxid, ev_xip, ev_type , ev_data1, ev_data2, ev_data3, ev_data4    ) values ('1', '4896546', '2005-01-23 16:08:55.037395', '1745281261', '1745281262', '', 'ENABLE_SUBSCRIPTION', '25506', '1', '501', 't'); insert into "_livesystem".sl_confirm      (con_origin, con_received, con_seqno, con_timestamp)    values (1, 4, '4896546', CURRENT_TIMESTAMP); commit transaction;" PGRES_FATAL_ERROR ERROR:  insert or update on table "sl_subscribe" violates foreign key constraint "sl_subscribe-sl_path-ref"
DETAIL:  Key (sub_provider,sub_receiver)=(1,501) is not present in table "sl_path".</PRE
><P
> This is then followed by a series of failed syncs as the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> shuts down:</P
><PRE
CLASS="SCREEN"
>DEBUG2 remoteListenThread_1: queue event 1,4897517 SYNC
DEBUG2 remoteListenThread_1: queue event 1,4897518 SYNC
DEBUG2 remoteListenThread_1: queue event 1,4897519 SYNC
DEBUG2 remoteListenThread_1: queue event 1,4897520 SYNC
DEBUG2 remoteWorker_event: ignore new events due to shutdown
DEBUG2 remoteListenThread_1: queue event 1,4897521 SYNC
DEBUG2 remoteWorker_event: ignore new events due to shutdown
DEBUG2 remoteListenThread_1: queue event 1,4897522 SYNC
DEBUG2 remoteWorker_event: ignore new events due to shutdown
DEBUG2 remoteListenThread_1: queue event 1,4897523 SYNC</PRE
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If you see a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> shutting down with
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ignore new events due to shutdown</I
></SPAN
> log entries,
you typically need to step back in the log to
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>before</I
></SPAN
> they started failing to see indication of
the root cause of the problem.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In this particular case, the problem was that some of
the <A
HREF="stmtstorepath.html"
>SLONIK STORE
     PATH</A
> commands had not yet made it to
node 4 before the <A
HREF="stmtsubscribeset.html"
>SLONIK SUBSCRIBE SET</A
> command
propagated. </P
><P
>This demonstrates yet another example of the need to not do
things in a rush; you need to be sure things are working right
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>before</I
></SPAN
> making further configuration changes.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9029"
></A
><B
>7.1.5.7. </B
>I just used <A
HREF="stmtmoveset.html"
>SLONIK MOVE SET</A
> to move the
origin to a new node.  Unfortunately, some subscribers are still
pointing to the former origin node, so I can't take it out of service
for maintenance without stopping them from getting updates.  What do I
do?  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You need to use <A
HREF="stmtsubscribeset.html"
>SLONIK SUBSCRIBE SET</A
> to
alter the subscriptions for those nodes to have them subscribe to a
provider that <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>will</I
></SPAN
> be sticking around during the
maintenance.</P
><DIV
CLASS="WARNING"
><P
></P
><TABLE
CLASS="WARNING"
BORDER="1"
WIDTH="100%"
><TR
><TD
ALIGN="CENTER"
><B
>Warning</B
></TD
></TR
><TR
><TD
ALIGN="LEFT"
><P
> What you <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>don't</I
></SPAN
> do is to <A
HREF="stmtunsubscribeset.html"
>SLONIK UNSUBSCRIBE SET</A
>; that would require reloading all data
for the nodes from scratch later.&#13;</P
></TD
></TR
></TABLE
></DIV
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9041"
></A
><B
>7.1.5.8. </B
> After notification of a subscription on
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>another</I
></SPAN
> node, replication falls over, starting
with the following error message:</P
><PRE
CLASS="SCREEN"
>ERROR  remoteWorkerThread_1: "begin transaction; set transaction isolation level serializable; lock table "_livesystem".sl_config_lock; select "_livesystem".enableSubscription(25506, 1, 501); notify "_livesystem_Event"; notify "_livesystem_Confirm"; insert into "_livesystem".sl_event     (ev_origin, ev_seqno, ev_timestamp,      ev_minxid, ev_maxxid, ev_xip, ev_type , ev_data1, ev_data2, ev_data3, ev_data4    ) values ('1', '4896546', '2005-01-23 16:08:55.037395', '1745281261', '1745281262', '', 'ENABLE_SUBSCRIPTION', '25506', '1', '501', 't'); insert into "_livesystem".sl_confirm      (con_origin, con_received, con_seqno, con_timestamp)    values (1, 4, '4896546', CURRENT_TIMESTAMP); commit transaction;" PGRES_FATAL_ERROR ERROR:  insert or update on table "sl_subscribe" violates foreign key constraint "sl_subscribe-sl_path-ref"
DETAIL:  Key (sub_provider,sub_receiver)=(1,501) is not present in table "sl_path".</PRE
><P
> This is then followed by a series of failed syncs as the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> shuts down:

</P><PRE
CLASS="SCREEN"
>DEBUG2 remoteListenThread_1: queue event 1,4897517 SYNC
DEBUG2 remoteListenThread_1: queue event 1,4897518 SYNC
DEBUG2 remoteListenThread_1: queue event 1,4897519 SYNC
DEBUG2 remoteListenThread_1: queue event 1,4897520 SYNC
DEBUG2 remoteWorker_event: ignore new events due to shutdown
DEBUG2 remoteListenThread_1: queue event 1,4897521 SYNC
DEBUG2 remoteWorker_event: ignore new events due to shutdown
DEBUG2 remoteListenThread_1: queue event 1,4897522 SYNC
DEBUG2 remoteWorker_event: ignore new events due to shutdown
DEBUG2 remoteListenThread_1: queue event 1,4897523 SYNC</PRE
><P>&#13;</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If you see a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> shutting down with
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ignore new events due to shutdown</I
></SPAN
> log entries,
you'll typically have to step back to <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>before</I
></SPAN
> they
started failing to see indication of the root cause of the problem.&#13;</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In this particular case, the problem was that some of
the <A
HREF="stmtstorepath.html"
>SLONIK STORE
     PATH</A
> commands had not yet made it to
node 4 before the <A
HREF="stmtsubscribeset.html"
>SLONIK SUBSCRIBE SET</A
> command
propagated. </P
><P
>This is yet another example of the need to not do things too
terribly quickly; you need to be sure things are working right
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>before</I
></SPAN
> making further configuration changes.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9060"
></A
><B
>7.1.5.9. </B
> Is the ordering of tables in a set significant?</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Most of the time, it isn't.  You might imagine it of
some value to order the tables in some particular way in order that
<SPAN
CLASS="QUOTE"
>"parent"</SPAN
> entries would make it in before their
<SPAN
CLASS="QUOTE"
>"children"</SPAN
> in some foreign key relationship; that
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>isn't</I
></SPAN
> the case since foreign key constraint
triggers are turned off on subscriber nodes.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
>(Jan Wieck comments) The order of table ID's is only
significant during a <A
HREF="stmtlockset.html"
>SLONIK LOCK SET</A
> in preparation of
switchover. If that order is different from the order in which an
application is acquiring its locks, it can lead to deadlocks that
abort either the application or <SPAN
CLASS="APPLICATION"
>slon</SPAN
>.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> (David Parker) I ran into one other case where the
ordering of tables in the set was significant: in the presence of
inherited tables. If a child table appears before its parent in a set,
then the initial subscription will end up deleting that child table
after it has possibly already received data, because the
<TT
CLASS="COMMAND"
>copy_set</TT
> logic does a <TT
CLASS="COMMAND"
>delete</TT
>,
not a <TT
CLASS="COMMAND"
>delete only</TT
>, so the delete of the parent will
delete the new rows in the child as well.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9077"
></A
><B
>7.1.5.10. </B
> If you have a <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
> script
something like this, it will hang on you and never complete, because
you can't have <A
HREF="stmtwaitevent.html"
>SLONIK WAIT FOR EVENT</A
> inside a <A
HREF="slonikref.html#TRYBLOCK"
>Section 1.3</A
> block. A <TT
CLASS="COMMAND"
>try</TT
> block is executed
as one transaction, and the event that you are waiting for can never
arrive inside the scope of the transaction.</P
><PRE
CLASS="PROGRAMLISTING"
>try {
      echo 'Moving set 1 to node 3';
      lock set (id=1, origin=1);
      echo 'Set locked';
      wait for event (origin = 1, confirmed = 3);
      echo 'Moving set';
      move set (id=1, old origin=1, new origin=3);
      echo 'Set moved - waiting for event to be confirmed by node 3';
      wait for event (origin = 1, confirmed = 3);
      echo 'Confirmed';
} on error {
      echo 'Could not move set for cluster foo';
      unlock set (id=1, origin=1);
      exit -1;
}</PRE
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>must not</I
></SPAN
> invoke <A
HREF="stmtwaitevent.html"
>SLONIK WAIT FOR EVENT</A
> inside a <SPAN
CLASS="QUOTE"
>"try"</SPAN
>
block.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9090"
></A
><B
>7.1.5.11. </B
>Slony-I: cannot add table to currently subscribed set 1</P
><P
> I tried to add a table to a set, and got the following message:

</P><PRE
CLASS="SCREEN"
>	Slony-I: cannot add table to currently subscribed set 1</PRE
><P></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You cannot add tables to sets that already have
subscribers.</P
><P
>The workaround to this is to create <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ANOTHER</I
></SPAN
>
set, add the new tables to that new set, subscribe the same nodes
subscribing to "set 1" to the new set, and then merge the sets
together.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9099"
></A
><B
>7.1.5.12. </B
>ERROR: duplicate key violates unique constraint "sl_table-pkey"</P
><P
>I tried setting up a second replication set, and got the following error:

</P><PRE
CLASS="SCREEN"
>stdin:9: Could not create subscription set 2 for oxrslive!
stdin:11: PGRES_FATAL_ERROR select "_oxrslive".setAddTable(2, 1, 'public.replic_test', 'replic_test__Slony-I_oxrslive_rowID_key', 'Table public.replic_test without primary key');  - ERROR:  duplicate key violates unique constraint "sl_table-pkey"
CONTEXT:  PL/pgSQL function "setaddtable_int" line 71 at SQL statement</PRE
><P></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The table IDs used in <A
HREF="stmtsetaddtable.html"
>SLONIK SET ADD TABLE</A
>
are required to be unique <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>ACROSS ALL SETS</I
></SPAN
>.  Thus,
you can't restart numbering at 1 for a second set; if you are
numbering them consecutively, a subsequent set has to start with IDs
after where the previous set(s) left off.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9108"
></A
><B
>7.1.5.13. </B
> One of my nodes fell over (<A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> / postmaster was
down) and nobody noticed for several days.  Now, when the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> for
that node starts up, it runs for about five minutes, then terminates,
with the error message: <TT
CLASS="COMMAND"
>ERROR: remoteListenThread_%d: timeout
for event selection</TT
> What's wrong, and what do I do? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The problem is that the listener thread (in
<TT
CLASS="FILENAME"
>src/slon/remote_listener.c</TT
>) timed out when trying
to determine what events were outstanding for that node.  By default,
the query will run for five minutes; if there were many days worth of
outstanding events, this might take too long.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> On versions of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> before 1.1.7, 1.2.7, and 1.3, a
solution was to increase the timeout in
<TT
CLASS="FILENAME"
>src/slon/remote_listener.c</TT
>, recompile <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
>,
and retry. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Another would be to treat the node as having failed,
and use the <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
> command <A
HREF="stmtdropnode.html"
>SLONIK DROP NODE</A
> to drop the
node, and recreate it.  If the database is heavily updated, it may
well be cheaper to do this than it is to find a way to let it catch
up.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In newer versions of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>, there is a new
configuration parameter called <A
HREF="slon-config-interval.html#SLON-CONFIG-REMOTE-LISTEN-TIMEOUT"
>slon_conf_remote_listen_timeout</A
>; you'd alter the config
file to increase the timeout, and try again.  Of course, as mentioned
above, it could be faster to drop the node and recreate it than it is
to require it to catch up across a week's worth of updates...  </P
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQPERFORMANCE"
></A
>6.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Performance Issues </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9133"
></A
><B
>7.1.6.1. </B
> Replication has been slowing down, I'm seeing
<TT
CLASS="COMMAND"
> FETCH 100 FROM LOG </TT
> queries running for a long
time, <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> is growing, and performance is, well,
generally getting steadily worse. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> There are actually a number of possible causes for
this sort of thing.  There is a question involving similar pathology
where the problem is that <A
HREF="appendix.html#PGLISTENERFULL"
> <TT
CLASS="ENVAR"
>pg_listener</TT
>
grows because it is not vacuumed. </A
></P
><P
> Another <SPAN
CLASS="QUOTE"
>" proximate cause "</SPAN
> for this growth is for
there to be a connection connected to the node that sits <TT
CLASS="COMMAND"
>IDLE IN TRANSACTION </TT
> for a very long time. </P
><P
> That open transaction will have multiple negative effects, all
of which will adversely affect performance:</P
><P
></P
><UL
><LI
><P
> Vacuums on all tables, including <TT
CLASS="ENVAR"
>pg_listener</TT
>, will
not clear out dead tuples from before the start of the idle
transaction. </P
></LI
><LI
><P
> The cleanup thread will be unable to clean out
entries in <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>, <A
HREF="table.sl-log-2.html"
>sl_log_2</A
>, and <A
HREF="table.sl-seqlog.html"
>sl_seqlog</A
>, with the result that
these tables will grow, ceaselessly, until the transaction is
closed. </P
></LI
></UL
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You can monitor for this condition inside the database
only if the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> <TT
CLASS="FILENAME"
> postgresql.conf </TT
>
parameter <TT
CLASS="ENVAR"
>stats_command_string</TT
> is set to true.  If that
is set, then you may submit the query <TT
CLASS="COMMAND"
> select * from
pg_stat_activity where current_query like '%IDLE% in transaction';</TT
> which will find relevant activity.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You should also be able to search for <SPAN
CLASS="QUOTE"
>" idle in
transaction "</SPAN
> in the process table to find processes that are
thus holding on to an ancient transaction.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> It is also possible (though rarer) for the problem to
be a transaction that is, for some other reason, being held open for a
very long time.  The <TT
CLASS="ENVAR"
> query_start </TT
> time in <TT
CLASS="ENVAR"
>pg_stat_activity </TT
> may show you some query that has been
running way too long.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> There are plans for <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> to have a timeout
parameter, <TT
CLASS="ENVAR"
> open_idle_transaction_timeout </TT
>, which would
cause old transactions to time out after some period of disuse.  Buggy
connection pool logic is a common culprit for this sort of thing.
There are plans for <SPAN
CLASS="PRODUCTNAME"
> <A
HREF="help.html#PGPOOL"
> pgpool</A
> </SPAN
> to provide a better alternative, eventually,
where connections would be shared inside a connection pool implemented
in C.  You may have some more or less buggy connection pool in your
Java or PHP application; if a small set of <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
> real </I
></SPAN
>
connections are held in <SPAN
CLASS="PRODUCTNAME"
>pgpool</SPAN
>, that will
hide from the database the fact that the application imagines that
numerous of them are left idle in transaction for hours at a time.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9177"
></A
><B
>7.1.6.2. </B
>After dropping a node, <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
>
aren't getting purged out anymore.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This is a common scenario in versions before 1.0.5, as
the <SPAN
CLASS="QUOTE"
>"clean up"</SPAN
> that takes place when purging the node
does not include purging out old entries from the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> table,
<A
HREF="table.sl-confirm.html"
>sl_confirm</A
>, for the recently departed
node.</P
><P
> The node is no longer around to update confirmations of what
syncs have been applied on it, and therefore the cleanup thread that
purges log entries thinks that it can't safely delete entries newer
than the final <A
HREF="table.sl-confirm.html"
>sl_confirm</A
> entry, which rather
curtails the ability to purge out old logs.</P
><P
>Diagnosis: Run the following query to see if there are any
<SPAN
CLASS="QUOTE"
>"phantom/obsolete/blocking"</SPAN
> <A
HREF="table.sl-confirm.html"
>sl_confirm</A
> entries:

</P><PRE
CLASS="SCREEN"
>oxrsbar=# select * from _oxrsbar.sl_confirm where con_origin not in (select no_id from _oxrsbar.sl_node) or con_received not in (select no_id from _oxrsbar.sl_node);
 con_origin | con_received | con_seqno |        con_timestamp                  
------------+--------------+-----------+----------------------------
          4 |          501 |     83999 | 2004-11-09 19:57:08.195969
          1 |            2 |   3345790 | 2004-11-14 10:33:43.850265
          2 |          501 |    102718 | 2004-11-14 10:33:47.702086
        501 |            2 |      6577 | 2004-11-14 10:34:45.717003
          4 |            5 |     83999 | 2004-11-14 21:11:11.111686
          4 |            3 |     83999 | 2004-11-24 16:32:39.020194
(6 rows)</PRE
><P></P
><P
>In version 1.0.5, the <A
HREF="stmtdropnode.html"
>SLONIK DROP NODE</A
> function
purges out entries in <A
HREF="table.sl-confirm.html"
>sl_confirm</A
> for the
departing node.  In earlier versions, this needs to be done manually.
Supposing the node number is 3, then the query would be:

</P><PRE
CLASS="SCREEN"
>delete from _namespace.sl_confirm where con_origin = 3 or con_received = 3;</PRE
><P></P
><P
>Alternatively, to go after <SPAN
CLASS="QUOTE"
>"all phantoms,"</SPAN
> you could use
</P><PRE
CLASS="SCREEN"
>oxrsbar=# delete from _oxrsbar.sl_confirm where con_origin not in (select no_id from _oxrsbar.sl_node) or con_received not in (select no_id from _oxrsbar.sl_node);
DELETE 6</PRE
><P></P
><P
>General <SPAN
CLASS="QUOTE"
>"due diligence"</SPAN
> dictates starting with a
<TT
CLASS="COMMAND"
>BEGIN</TT
>, looking at the contents of
<A
HREF="table.sl-confirm.html"
>sl_confirm</A
> before, ensuring that only the expected
records are purged, and then, only after that, confirming the change
with a <TT
CLASS="COMMAND"
>COMMIT</TT
>.  If you delete confirm entries for
the wrong node, that could ruin your whole day.</P
><P
>You'll need to run this on each node that remains...</P
><P
>Note that as of 1.0.5, this is no longer an issue at all, as it
purges unneeded entries from <A
HREF="table.sl-confirm.html"
>sl_confirm</A
> in two
places:

<P
></P
></P><UL
><LI
><P
> At the time a node is dropped</P
></LI
><LI
><P
> At the start of each
<CODE
CLASS="FUNCTION"
>cleanupEvent</CODE
> run, which is the event in which old
data is purged from <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>, <A
HREF="table.sl-log-2.html"
>sl_log_2</A
>, and
<A
HREF="table.sl-seqlog.html"
>sl_seqlog</A
></P
></LI
></UL
><P></P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9217"
></A
><B
>7.1.6.3. </B
>The <SPAN
CLASS="APPLICATION"
>slon</SPAN
> spent the weekend out of
commission [for some reason], and it's taking a long time to get a
sync through.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You might want to take a look at the tables <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>
and <A
HREF="table.sl-log-2.html"
>sl_log_2</A
> and do a summary to see if there are any really enormous
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> transactions in there.  Up until at least 1.0.2, there needs
to be a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> connected to the origin in order for
<TT
CLASS="COMMAND"
>SYNC</TT
> events to be generated.</P
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Note: </B
> As of 1.0.2,
function <CODE
CLASS="FUNCTION"
>generate_sync_event()</CODE
> provides an
alternative as backup...</P
></BLOCKQUOTE
></DIV
><P
>If none are being generated, then all of the updates until the
next one is generated will collect into one rather enormous <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
transaction.</P
><P
>Conclusion: Even if there is not going to be a subscriber
around, you <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>really</I
></SPAN
> want to have a
<SPAN
CLASS="APPLICATION"
>slon</SPAN
> running to service the origin
node.</P
><P
><SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.1 and later versions provide a stored procedure that
allows <TT
CLASS="COMMAND"
>SYNC</TT
> counts to be updated on the origin
based on a <SPAN
CLASS="APPLICATION"
>cron</SPAN
> job even if there is no
<A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> daemon running.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9241"
></A
><B
>7.1.6.4. </B
> I have submitted a <A
HREF="stmtmoveset.html"
>SLONIK MOVE SET</A
> / <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
> request, and
it seems to be stuck on one of my nodes.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> logs aren't
displaying any errors or warnings </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Is it possible that you are running
<SPAN
CLASS="APPLICATION"
>pg_autovacuum</SPAN
>, and it has taken out locks
on some tables in the replication set?  That would somewhat-invisibly
block <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> from performing operations that require locking acquisition 
of exclusive locks. </P
><P
> You might check for these sorts of locks using the following
query: <TT
CLASS="COMMAND"
> select l.*, c.relname from pg_locks l, pg_class c
where c.oid = l.relation ; </TT
> </P
><P
> A <TT
CLASS="ENVAR"
>ShareUpdateExclusiveLock</TT
> lock will block the
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> operations that need their own exclusive locks, which are
likely queued up, marked as not being granted. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9256"
></A
><B
>7.1.6.5. </B
> I'm noticing in the logs that a <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> is frequently
switching in and out of <SPAN
CLASS="QUOTE"
>"polling"</SPAN
> mode as it is
frequently reporting <SPAN
CLASS="QUOTE"
>"LISTEN - switch from polling mode to use
LISTEN"</SPAN
> and <SPAN
CLASS="QUOTE"
>"UNLISTEN - switch into polling
mode"</SPAN
>. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The thresholds for switching between these modes are
controlled by the configuration parameters <A
HREF="slon-config-interval.html#SLON-CONFIG-SYNC-INTERVAL"
>slon_conf_sync_interval</A
> and <A
HREF="slon-config-interval.html#SLON-CONFIG-SYNC-INTERVAL-TIMEOUT"
>slon_conf_sync_interval_timeout</A
>; if the timeout value
(which defaults to 10000, implying 10s) is kept low, that makes it
easy for the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> to decide to return to <SPAN
CLASS="QUOTE"
>"listening"</SPAN
>
mode.  You may want to increase the value of the timeout
parameter. </P
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQBUGS"
></A
>7.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> Bugs in Elder Versions </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9273"
></A
><B
>7.1.7.1. </B
>The <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes servicing my
subscribers are growing to enormous size, challenging system resources
both in terms of swap space as well as moving towards breaking past
the 2GB maximum process size on my system. </P
><P
> By the way, the data that I am replicating includes some rather
large records.  We have records that are tens of megabytes in size.
Perhaps that is somehow relevant? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Yes, those very large records are at the root of the
problem.  The problem is that <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> normally draws in
about 100 records at a time when a subscriber is processing the query
which loads data from the provider.  Thus, if the average record size
is 10MB, this will draw in 1000MB of data which is then transformed
into <TT
CLASS="COMMAND"
>INSERT</TT
> or <TT
CLASS="COMMAND"
>UPDATE</TT
>
statements, in the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> process' memory.</P
><P
> That obviously leads to <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> growing to a
fairly tremendous size. </P
><P
> The number of records that are fetched is controlled by the
value <TT
CLASS="ENVAR"
> SLON_DATA_FETCH_SIZE </TT
>, which is defined in the
file <TT
CLASS="FILENAME"
>src/slon/slon.h</TT
>.  The relevant extract of
this is shown below. </P
><PRE
CLASS="PROGRAMLISTING"
>#ifdef	SLON_CHECK_CMDTUPLES
#define SLON_COMMANDS_PER_LINE		1
#define SLON_DATA_FETCH_SIZE		100
#define SLON_WORKLINES_PER_HELPER	(SLON_DATA_FETCH_SIZE * 4)
#else
#define SLON_COMMANDS_PER_LINE		10
#define SLON_DATA_FETCH_SIZE		10
#define SLON_WORKLINES_PER_HELPER	(SLON_DATA_FETCH_SIZE * 50)
#endif</PRE
><P
> If you are experiencing this problem, you might modify the
definition of <TT
CLASS="ENVAR"
> SLON_DATA_FETCH_SIZE </TT
>, perhaps reducing
by a factor of 10, and recompile <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
>.  There are two
definitions as <TT
CLASS="ENVAR"
> SLON_CHECK_CMDTUPLES</TT
> allows doing some
extra monitoring to ensure that subscribers have not fallen out of
SYNC with the provider.  By default, this option is turned off, so the
default modification to make is to change the second definition of
<TT
CLASS="ENVAR"
> SLON_DATA_FETCH_SIZE </TT
> from 10 to 1. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In version 1.2, configuration values <A
HREF="slon-config-interval.html#SLON-CONFIG-MAX-ROWSIZE"
>sync_max_rowsize</A
> and <A
HREF="slon-config-interval.html#SLON-CONFIG-MAX-LARGEMEM"
>sync_max_largemem</A
> are associated with a new
algorithm that changes the logic as follows.  Rather than fetching 100
rows worth of data at a time:</P
><P
></P
><UL
><LI
><P
> The <TT
CLASS="COMMAND"
>fetch from LOG</TT
> query will draw
in 500 rows at a time where the size of the attributes does not exceed
<A
HREF="slon-config-interval.html#SLON-CONFIG-MAX-ROWSIZE"
>sync_max_rowsize</A
>.  With default values, this
restricts this aspect of memory consumption to about 8MB.  </P
></LI
><LI
><P
> Tuples with larger attributes are loaded until
aggregate size exceeds the parameter <A
HREF="slon-config-interval.html#SLON-CONFIG-MAX-LARGEMEM"
>sync_max_largemem</A
>.  By default, this restricts
consumption of this sort to about 5MB.  This value is not a strict
upper bound; if you have a tuple with attributes 50MB in size, it
forcibly <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>must</I
></SPAN
> be loaded into memory.  There is no
way around that.  But <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> at least won't be trying
to load in 100 such records at a time, chewing up 10GB of memory by
the time it's done.  </P
></LI
></UL
><P
> This should alleviate problems people have been experiencing
when they sporadically have series' of very large tuples. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In version 2.2, this is eliminated in a different way,
as the log data is transported using COPY rather than via querying
from a cursor, which may be expected to be a
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>massive</I
></SPAN
> improvement to the "flow control"
here. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9313"
></A
><B
>7.1.7.2. </B
> I am trying to replicate
<TT
CLASS="ENVAR"
>UNICODE</TT
> data from <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.0 to <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.1, and
am experiencing problems. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.1 is quite a lot more strict about what
UTF-8 mappings of Unicode characters it accepts as compared to version
8.0.</P
><P
> If you intend to use <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to update an older database to 8.1, and
might have invalid UTF-8 values, you may be for an unpleasant
surprise.</P
><P
> Let us suppose we have a database running 8.0, encoding in UTF-8.
That database will accept the sequence <TT
CLASS="COMMAND"
>'\060\242'</TT
> as UTF-8 compliant,
even though it is really not. </P
><P
> If you replicate into a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.1 instance, it will complain
about this, either at subscribe time, where <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> will complain
about detecting an invalid Unicode sequence during the COPY of the
data, which will prevent the subscription from proceeding, or, upon
adding data, later, where this will hang up replication fairly much
irretrievably.  (You could hack on the contents of sl_log_1, but
that quickly gets <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>really</I
></SPAN
> unattractive...)</P
><P
>There have been discussions as to what might be done about this.  No
compelling strategy has yet emerged, as all are unattractive. </P
><P
>If you are using Unicode with <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.0, you run a
considerable risk of corrupting data.  </P
><P
> If you use replication for a one-time conversion, there is a risk of
failure due to the issues mentioned earlier; if that happens, it
appears likely that the best answer is to fix the data on the 8.0
system, and retry. </P
><P
> In view of the risks, running replication between versions seems to be
something you should not keep running any longer than is necessary to
migrate to 8.1. </P
><P
> For more details, see the <A
HREF="http://archives.postgresql.org/pgsql-hackers/2005-12/msg00181.php"
TARGET="_top"
>discussion on postgresql-hackers mailing list. </A
>.  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9337"
></A
><B
>7.1.7.3. </B
> I am running <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.1 and have a 4+ node setup
where there are two subscription sets, 1 and 2, that do not share any
nodes.  I am discovering that confirmations for set 1 never get to the
nodes subscribing to set 2, and that confirmations for set 2 never get
to nodes subscribing to set 1.  As a result, <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> grow
and grow, and are never purged.  This was reported as
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> <A
HREF="http://gborg.postgresql.org/project/slony1/bugs/bugupdate.php?1485"
TARGET="_top"
>bug 1485 </A
>.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Apparently the code for
<CODE
CLASS="FUNCTION"
>RebuildListenEntries()</CODE
> does not suffice for this
case.</P
><P
> <CODE
CLASS="FUNCTION"
> RebuildListenEntries()</CODE
> will be replaced
in <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> version 1.2 with an algorithm that covers this case. </P
><P
> In the interim, you'll want to manually add some <A
HREF="table.sl-listen.html"
>sl_listen</A
> entries using <A
HREF="stmtstorelisten.html"
>SLONIK STORE LISTEN</A
> or <CODE
CLASS="FUNCTION"
>storeListen()</CODE
>,
based on the (apparently not as obsolete as we thought) principles
described in <A
HREF="listenpaths.html"
>Section 4.2</A
>.&#13;</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9356"
></A
><B
>7.1.7.4. </B
> I am finding some multibyte columns (Unicode, Big5)
are being truncated a bit, clipping off the last character.  Why?</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This was a bug present until a little after <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
version 1.1.0; the way in which columns were being captured by the
<CODE
CLASS="FUNCTION"
>logtrigger()</CODE
> function could clip off the last
byte of a column represented in a multibyte format.  Check to see that
your version of <TT
CLASS="FILENAME"
>src/backend/slony1_funcs.c</TT
> is
1.34 or better; the patch was introduced in CVS version 1.34 of that
file.  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9364"
></A
><B
>7.1.7.5. </B
> <A
HREF="http://gborg.postgresql.org/project/slony1/bugs/bugupdate.php?1226"
TARGET="_top"
>Bug #1226 </A
> indicates an error condition that can come up if
you have a replication set that consists solely of sequences. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The  short answer is that having a replication set
consisting only of sequences is not a 
best practice. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The problem with a sequence-only set comes up only if you have
a case where the only subscriptions that are active for a particular
subscriber to a particular provider are for
<SPAN
CLASS="QUOTE"
>"sequence-only"</SPAN
> sets.  If a node gets into that state,
replication will fail, as the query that looks for data from
<A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> has no tables to find, and the query will be
malformed, and fail.  If a replication set <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>with</I
></SPAN
>
tables is added back to the mix, everything will work out fine; it
just <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>seems</I
></SPAN
> scary.</P
><P
> This problem should be resolved some time after <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
1.1.0.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9379"
></A
><B
>7.1.7.6. </B
>I need to drop a table from a replication set</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
>This can be accomplished several ways, not all equally desirable ;-).

<P
></P
></P><UL
><LI
><P
> You could drop the whole replication set, and
recreate it with just the tables that you need.  Alas, that means
recopying a whole lot of data, and kills the usability of the cluster
on the rest of the set while that's happening.</P
></LI
><LI
><P
> If you are running 1.0.5 or later, there is the
command SET DROP TABLE, which will "do the trick."</P
></LI
><LI
><P
> If you are still using 1.0.1 or 1.0.2, the
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>essential functionality of <A
HREF="stmtsetdroptable.html"
>SLONIK SET DROP TABLE</A
>
involves the functionality in <CODE
CLASS="FUNCTION"
>droptable_int()</CODE
>.
You can fiddle this by hand by finding the table ID for the table you
want to get rid of, which you can find in <A
HREF="table.sl-table.html"
>sl_table</A
>, and then run the following three queries,
on each host:</I
></SPAN
>

</P><PRE
CLASS="PROGRAMLISTING"
>  select _slonyschema.alterTableRestore(40);
  select _slonyschema.tableDropKey(40);
  delete from _slonyschema.sl_table where tab_id = 40;</PRE
><P></P
><P
>The schema will obviously depend on how you defined the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
cluster.  The table ID, in this case, 40, will need to change to the
ID of the table you want to have go away.</P
><P
> You'll have to run these three queries on all of the nodes,
preferably firstly on the origin node, so that the dropping of this
propagates properly.  Implementing this via a <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
>
statement with a new <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> event would do that.  Submitting the
three queries using <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
> could do that.
Also possible would be to connect to each database and submit the
queries by hand.</P
></LI
></UL
><P></P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9402"
></A
><B
>7.1.7.7. </B
>I need to drop a sequence from a replication set</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
></P
><P
>If you are running 1.0.5 or later, there is
a <A
HREF="stmtsetdropsequence.html"
>SLONIK SET DROP SEQUENCE</A
> command in Slonik to allow you
to do this, parallelling <A
HREF="stmtsetdroptable.html"
>SLONIK SET DROP TABLE</A
>.</P
><P
>If you are running 1.0.2 or earlier, the process is a bit more manual.</P
><P
>Supposing I want to get rid of the two sequences listed below,
<TT
CLASS="ENVAR"
>whois_cachemgmt_seq</TT
> and
<TT
CLASS="ENVAR"
>epp_whoi_cach_seq_</TT
>, we start by needing the
<TT
CLASS="ENVAR"
>seq_id</TT
> values.

</P><PRE
CLASS="SCREEN"
>oxrsorg=# select * from _oxrsorg.sl_sequence  where seq_id in (93,59);
 seq_id | seq_reloid | seq_set |       seq_comment				 
--------+------------+---------+-------------------------------------
     93 |  107451516 |       1 | Sequence public.whois_cachemgmt_seq
     59 |  107451860 |       1 | Sequence public.epp_whoi_cach_seq_
(2 rows)</PRE
><P></P
><P
>The data that needs to be deleted to stop Slony from continuing to
replicate these are thus:

</P><PRE
CLASS="PROGRAMLISTING"
>delete from _oxrsorg.sl_seqlog where seql_seqid in (93, 59);
delete from _oxrsorg.sl_sequence where seq_id in (93,59);</PRE
><P></P
><P
>Those two queries could be submitted to all of the nodes via
<A
HREF="function.ddlscript-complete-p-nodes-text.html"
>schemadocddlscript_complete(p_nodes text)</A
> / <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
>, thus eliminating the sequence everywhere
<SPAN
CLASS="QUOTE"
>"at once."</SPAN
> Or they may be applied by hand to each of the
nodes.</P
><P
>Similarly to <A
HREF="stmtsetdroptable.html"
>SLONIK SET DROP TABLE</A
>, this is
implemented <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> version 1.0.5 as <A
HREF="stmtsetdropsequence.html"
>SLONIK SET DROP SEQUENCE</A
>.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9426"
></A
><B
>7.1.7.8. </B
> I set up my cluster using pgAdminIII, with cluster
name <SPAN
CLASS="QUOTE"
>"MY-CLUSTER"</SPAN
>.  Time has passed, and I tried using
Slonik to make a configuration change, and this is failing with the
following error message:</P
><PRE
CLASS="PROGRAMLISTING"
>ERROR: syntax error at or near -</PRE
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The problem here is that <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> expects cluster names
to be valid <A
HREF="http://www.postgresql.org/docs/8.3/static/sql-syntax-lexical.html"
TARGET="_top"
>SQL Identifiers</A
>, and <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
> enforces this.  Unfortunately,
<SPAN
CLASS="APPLICATION"
>pgAdminIII</SPAN
> did not do so, and allowed using
a cluster name that now causes <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>a problem.</I
></SPAN
> </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If you have gotten into this spot, it's a problem that
we mayn't be help resolve, terribly much.  </P
><P
> It's <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>conceivably possible</I
></SPAN
> that running the
SQL command <TT
CLASS="COMMAND"
>alter namespace "_My-Bad-Clustername" rename to
"_BetterClusterName";</TT
> against each database may work.  That
shouldn't particularly <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>damage</I
></SPAN
> things!</P
><P
> On the other hand, when the problem has been experienced, users
have found they needed to drop replication and rebuild the
cluster.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> A change in version 2.0.2 is that a function runs as
part of loading functions into the database which checks the validity
of the cluster name.  If you try to use an invalid cluster name,
loading the functions will fail, with a suitable error message, which
should prevent things from going wrong even if you're using tools
other than <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
> to manage setting up the cluster. </P
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><H3
><A
NAME="FAQOBSOLETE"
></A
>8.  <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> FAQ: Anachronisms -
Hopefully Obsolete </H3
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9451"
></A
><B
>7.1.8.1. </B
> <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> does not restart after
crash</P
><P
> After an immediate stop of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> (simulation of system
crash) in <TT
CLASS="ENVAR"
>pg_listener</TT
> a tuple with <TT
CLASS="COMMAND"
>relname='_${cluster_name}_Restart'</TT
> exists. slon doesn't
start because it thinks another process is serving the cluster on this
node.  What can I do? The tuples can't be dropped from this
relation.</P
><P
> The logs claim that <A
NAME="AEN9459"
></A
><BLOCKQUOTE
CLASS="BLOCKQUOTE"
><P
>Another slon daemon is
serving this node already</P
></BLOCKQUOTE
></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The problem is that the system table <TT
CLASS="ENVAR"
>pg_listener</TT
>, used
by <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> to manage event notifications, contains some entries
that are pointing to backends that no longer exist.  The new <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> instance connects to the database, and is convinced,
by the presence of these entries, that an old
<SPAN
CLASS="APPLICATION"
>slon</SPAN
> is still servicing this <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
node.</P
><P
> The <SPAN
CLASS="QUOTE"
>"trash"</SPAN
> in that table needs to be thrown
away.</P
><P
>It's handy to keep a slonik script similar to the following to
run in such cases:

</P><PRE
CLASS="PROGRAMLISTING"
>twcsds004[/opt/twcsds004/OXRS/slony-scripts]$ cat restart_org.slonik 
cluster name = oxrsorg ;
node 1 admin conninfo = 'host=32.85.68.220 dbname=oxrsorg user=postgres port=5532';
node 2 admin conninfo = 'host=32.85.68.216 dbname=oxrsorg user=postgres port=5532';
node 3 admin conninfo = 'host=32.85.68.244 dbname=oxrsorg user=postgres port=5532';
node 4 admin conninfo = 'host=10.28.103.132 dbname=oxrsorg user=postgres port=5532';
restart node 1;
restart node 2;
restart node 3;
restart node 4;</PRE
><P></P
><P
> <A
HREF="stmtrestartnode.html"
>SLONIK RESTART NODE</A
> cleans up dead notifications
so that you can restart the node.</P
><P
>As of version 1.0.5, the startup process of slon looks for this
condition, and automatically cleans it up.</P
><P
> As of version 8.1 of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>, the functions that manipulate
<TT
CLASS="ENVAR"
>pg_listener</TT
> do not support this usage, so for <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> versions after
1.1.2 (<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>e.g. - </I
></SPAN
> 1.1.5), this
<SPAN
CLASS="QUOTE"
>"interlock"</SPAN
> behaviour is handled via a new table, and the
issue should be transparently <SPAN
CLASS="QUOTE"
>"gone."</SPAN
> </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9483"
></A
><B
>7.1.8.2. </B
> I tried the following query which did not work:</P
><PRE
CLASS="PROGRAMLISTING"
>sdb=# explain select query_start, current_query from pg_locks join
pg_stat_activity on pid = procpid where granted = true and transaction
in (select transaction from pg_locks where granted = false); 

ERROR: could not find hash function for hash operator 716373</PRE
><P
> It appears the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> <CODE
CLASS="FUNCTION"
>xxid</CODE
> functions are
claiming to be capable of hashing, but cannot actually do so.</P
><P
> What's up? </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> defined an XXID data type and operators on
that type in order to allow manipulation of transaction IDs that are
used to group together updates that are associated with the same
transaction.</P
><P
> Operators were not available for <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 7.3 and earlier
versions; in order to support version 7.3, custom functions had to be
added.  The <CODE
CLASS="FUNCTION"
>=</CODE
> operator was marked as supporting
hashing, but for that to work properly, the join operator must appear
in a hash index operator class.  That was not defined, and as a
result, queries (like the one above) that decide to use hash joins
will fail. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This has <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
> not </I
></SPAN
> been considered a
<SPAN
CLASS="QUOTE"
>"release-critical"</SPAN
> bug, as <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> does not internally
generate queries likely to use hash joins.  This problem shouldn't
injure <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>'s ability to continue replicating. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Future releases of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> (<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>e.g.</I
></SPAN
>
1.0.6, 1.1) will omit the <TT
CLASS="COMMAND"
>HASHES</TT
> indicator, so that</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Supposing you wish to repair an existing instance, so
that your own queries will not run afoul of this problem, you may do
so as follows: </P
><PRE
CLASS="PROGRAMLISTING"
>/* cbbrowne@[local]/dba2 slony_test1=*/ \x     
Expanded display is on.
/* cbbrowne@[local]/dba2 slony_test1=*/ select * from pg_operator where oprname = '=' 
and oprnamespace = (select oid from pg_namespace where nspname = 'public');
-[ RECORD 1 ]+-------------
oprname      | =
oprnamespace | 2200
oprowner     | 1
oprkind      | b
oprcanhash   | t
oprleft      | 82122344
oprright     | 82122344
oprresult    | 16
oprcom       | 82122365
oprnegate    | 82122363
oprlsortop   | 82122362
oprrsortop   | 82122362
oprltcmpop   | 82122362
oprgtcmpop   | 82122360
oprcode      | "_T1".xxideq
oprrest      | eqsel
oprjoin      | eqjoinsel

/* cbbrowne@[local]/dba2 slony_test1=*/ update pg_operator set oprcanhash = 'f' where 
oprname = '=' and oprnamespace = 2200 ;
UPDATE 1</PRE
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9511"
></A
><B
>7.1.8.3. </B
> I can do a <TT
CLASS="COMMAND"
>pg_dump</TT
>
and load the data back in much faster than the <TT
CLASS="COMMAND"
>SUBSCRIBE
SET</TT
> runs.  Why is that?  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> depends on there being an already existant
index on the primary key, and leaves all indexes alone whilst using
the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> <TT
CLASS="COMMAND"
>COPY</TT
> command to load the data.
Further hurting performance, the <TT
CLASS="COMMAND"
>COPY SET</TT
> event (an
event that the subscription process generates) starts by deleting the
contents of tables, which leaves the table full of dead tuples.</P
><P
> When you use <TT
CLASS="COMMAND"
>pg_dump</TT
> to dump the contents of
a database, and then load that, creation of indexes is deferred until
the very end.  It is <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>much</I
></SPAN
> more efficient to
create indexes against the entire table, at the end, than it is to
build up the index incrementally as each row is added to the
table.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If you can drop unnecessary indices while the
<TT
CLASS="COMMAND"
>COPY</TT
> takes place, that will improve performance
quite a bit.  If you can <TT
CLASS="COMMAND"
>TRUNCATE</TT
> tables that
contain data that is about to be eliminated, that will improve
performance <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>a lot.</I
></SPAN
> </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> version 1.1.5 and later versions should handle
this automatically; it <SPAN
CLASS="QUOTE"
>"thumps"</SPAN
> on the indexes in the
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> catalog to hide them, in much the same way triggers are
hidden, and then <SPAN
CLASS="QUOTE"
>"fixes"</SPAN
> the index pointers and reindexes
the table. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9536"
></A
><B
>7.1.8.4. </B
>Replication Fails - Unique Constraint Violation</P
><P
>Replication has been running for a while, successfully, when a
node encounters a <SPAN
CLASS="QUOTE"
>"glitch,"</SPAN
> and replication logs are filled with
repetitions of the following:

</P><PRE
CLASS="SCREEN"
>DEBUG2 remoteWorkerThread_1: syncing set 2 with 5 table(s) from provider 1
DEBUG2 remoteWorkerThread_1: syncing set 1 with 41 table(s) from provider 1
DEBUG2 remoteWorkerThread_1: syncing set 5 with 1 table(s) from provider 1
DEBUG2 remoteWorkerThread_1: syncing set 3 with 1 table(s) from provider 1
DEBUG2 remoteHelperThread_1_1: 0.135 seconds delay for first row
DEBUG2 remoteHelperThread_1_1: 0.343 seconds until close cursor
ERROR  remoteWorkerThread_1: "insert into "_oxrsapp".sl_log_1          (log_origin, log_xid, log_tableid,                log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '34', '35090538', 'D', '_rserv_ts=''9275244''');
delete from only public.epp_domain_host where _rserv_ts='9275244';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '34', '35090539', 'D', '_rserv_ts=''9275245''');
delete from only public.epp_domain_host where _rserv_ts='9275245';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '26', '35090540', 'D', '_rserv_ts=''24240590''');
delete from only public.epp_domain_contact where _rserv_ts='24240590';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '26', '35090541', 'D', '_rserv_ts=''24240591''');
delete from only public.epp_domain_contact where _rserv_ts='24240591';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '26', '35090542', 'D', '_rserv_ts=''24240589''');
delete from only public.epp_domain_contact where _rserv_ts='24240589';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '11', '35090543', 'D', '_rserv_ts=''36968002''');
delete from only public.epp_domain_status where _rserv_ts='36968002';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '11', '35090544', 'D', '_rserv_ts=''36968003''');
delete from only public.epp_domain_status where _rserv_ts='36968003';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '24', '35090549', 'I', '(contact_id,status,reason,_rserv_ts) values (''6972897'',''64'','''',''31044208'')');
insert into public.contact_status (contact_id,status,reason,_rserv_ts) values ('6972897','64','','31044208');insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '24', '35090550', 'D', '_rserv_ts=''18139332''');
delete from only public.contact_status where _rserv_ts='18139332';insert into "_oxrsapp".sl_log_1	  (log_origin, log_xid, log_tableid,		log_actionseq, log_cmdtype,		log_cmddata) values	  ('1', '919151224', '24', '35090551', 'D', '_rserv_ts=''18139333''');
delete from only public.contact_status where _rserv_ts='18139333';" ERROR:  duplicate key violates unique constraint "contact_status_pkey"
 - qualification was: 
ERROR  remoteWorkerThread_1: SYNC aborted</PRE
><P></P
><P
>The transaction rolls back, and
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> tries again, and again, and again.
The problem is with one of the <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>last</I
></SPAN
> SQL
statements, the one with <TT
CLASS="COMMAND"
>log_cmdtype = 'I'</TT
>.  That
isn't quite obvious; what takes place is that
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> groups 10 update queries together
to diminish the number of network round trips.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> A <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>certain</I
></SPAN
> cause for this has been
difficult to arrive at.</P
><P
>By the time we notice that there is a problem, the seemingly
missed delete transaction has been cleaned out of <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>, so there
appears to be no recovery possible.  What has seemed necessary, at
this point, is to drop the replication set (or even the node), and
restart replication from scratch on that node.</P
><P
>In <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.0.5, the handling of purges of <A
HREF="table.sl-log-1.html"
>sl_log_1</A
> became
more conservative, refusing to purge entries that haven't been
successfully synced for at least 10 minutes on all nodes.  It was not
certain that that would prevent the <SPAN
CLASS="QUOTE"
>"glitch"</SPAN
> from taking
place, but it seemed plausible that it might leave enough <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>
data to be able to do something about recovering from the condition or
at least diagnosing it more exactly.  And perhaps the problem was that
<A
HREF="table.sl-log-1.html"
>sl_log_1</A
> was being purged too aggressively, and this would resolve the
issue completely.</P
><P
> It is a shame to have to reconstruct a large replication node
for this; if you discover that this problem recurs, it may be an idea
to break replication down into multiple sets in order to diminish the
work involved in restarting replication.  If only one set has broken,
you may only need to unsubscribe/drop and resubscribe the one set.</P
><P
> In one case we found two lines in the SQL error message in the
log file that contained <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
> identical </I
></SPAN
> insertions
into <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>.  This <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
> ought </I
></SPAN
> to be impossible as
is a primary key on <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>.  The latest (somewhat) punctured theory
that comes from <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>that</I
></SPAN
> was that perhaps this PK
index has been corrupted (representing a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> bug), and that
perhaps the problem might be alleviated by running the query:</P
><PRE
CLASS="PROGRAMLISTING"
># reindex table _slonyschema.sl_log_1;</PRE
><P
> On at least one occasion, this has resolved the problem, so it
is worth trying this.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This problem has been found to represent a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
bug as opposed to one in <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>.  Version 7.4.8 was released with
two resolutions to race conditions that should resolve the issue.
Thus, if you are running a version of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> earlier than 7.4.8,
you should consider upgrading to resolve this.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9573"
></A
><B
>7.1.8.5. </B
>I started doing a backup using
<SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
>, and suddenly Slony
stops</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
>Ouch.  What happens here is a conflict between:
<P
></P
></P><UL
><LI
><P
> <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
>, which has taken
out an <TT
CLASS="COMMAND"
>AccessShareLock</TT
> on all of the tables in the
database, including the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> ones, and</P
></LI
><LI
><P
> A <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> sync event, which wants to grab a
<TT
CLASS="COMMAND"
>AccessExclusiveLock</TT
> on the table <A
HREF="table.sl-event.html"
>sl_event</A
>.</P
></LI
></UL
><P></P
><P
>The initial query that will be blocked is thus:

</P><PRE
CLASS="SCREEN"
>select "_slonyschema".createEvent('_slonyschema, 'SYNC', NULL);	  </PRE
><P></P
><P
>(You can see this in <TT
CLASS="ENVAR"
>pg_stat_activity</TT
>, if you
have query display turned on in
<TT
CLASS="FILENAME"
>postgresql.conf</TT
>)</P
><P
>The actual query combination that is causing the lock is from
the function <CODE
CLASS="FUNCTION"
>Slony_I_ClusterStatus()</CODE
>, found in
<TT
CLASS="FILENAME"
>slony1_funcs.c</TT
>, and is localized in the code that
does:

</P><PRE
CLASS="PROGRAMLISTING"
>  LOCK TABLE %s.sl_event;
  INSERT INTO %s.sl_event (...stuff...)
  SELECT currval('%s.sl_event_seq');</PRE
><P></P
><P
>The <TT
CLASS="COMMAND"
>LOCK</TT
> statement will sit there and wait
until <TT
CLASS="COMMAND"
>pg_dump</TT
> (or whatever else has pretty much any
kind of access lock on <A
HREF="table.sl-event.html"
>sl_event</A
>)
completes.</P
><P
>Every subsequent query submitted that touches
<A
HREF="table.sl-event.html"
>sl_event</A
> will block behind the
<CODE
CLASS="FUNCTION"
>createEvent</CODE
> call.</P
><P
>There are a number of possible answers to this:
<P
></P
></P><UL
><LI
><P
> Have <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> specify the
schema dumped using <TT
CLASS="OPTION"
>--schema=whatever</TT
>, and don't try
dumping the cluster's schema.</P
></LI
><LI
><P
> It would be nice to add an
<TT
CLASS="OPTION"
>--exclude-schema</TT
> option to
<SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> to exclude the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> cluster
schema.  Maybe in 8.2...</P
></LI
><LI
><P
>Note that 1.0.5 uses a more precise lock that is less
exclusive that alleviates this problem.</P
></LI
></UL
><P></P
></DIV
></DIV
></DIV
><DIV
CLASS="QANDADIV"
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9620"
></A
><B
>7.1.9.1. </B
> I was trying to request <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
> or <A
HREF="stmtmoveset.html"
>SLONIK MOVE SET</A
>, and found
messages as follows on one of the subscribers:</P
><PRE
CLASS="SCREEN"
>NOTICE: Slony-I: multiple instances of trigger defrazzle on table frobozz
NOTICE: Slony-I: multiple instances of trigger derez on table tron
ERROR: Slony-I: Unable to disable triggers</PRE
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The trouble would seem to be that you have added
triggers on tables whose names conflict with triggers that were hidden
by <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>. </P
><P
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> hides triggers (save for those <SPAN
CLASS="QUOTE"
>"unhidden"</SPAN
>
via <A
HREF="stmtstoretrigger.html"
>SLONIK STORE TRIGGER</A
>) by repointing them to the
primary key of the table.  In the case of foreign key triggers, or
other triggers used to do data validation, it should be quite
unnecessary to run them on a subscriber, as equivalent triggers should
have been invoked on the origin node.  In contrast, triggers that do
some form of <SPAN
CLASS="QUOTE"
>"cache invalidation"</SPAN
> are ones you might want
to have run on a subscriber.</P
><P
> The <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>Right Way</I
></SPAN
> to handle such triggers is
normally to use <A
HREF="stmtstoretrigger.html"
>SLONIK STORE TRIGGER</A
>, which tells
<SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> that a trigger should not get deactivated. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> But some intrepid DBA might take matters into their
own hands and install a trigger by hand on a subscriber, and the above
condition generally has that as the cause.  What to do?  What to do?</P
><P
> The answer is normally fairly simple: Drop out the
<SPAN
CLASS="QUOTE"
>"extra"</SPAN
> trigger on the subscriber before the event that
tries to restore them runs.  Ideally, if the DBA is particularly
intrepid, and aware of this issue, that should take place
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>before</I
></SPAN
> there is ever a chance for the error
message to appear.  </P
><P
> If the DBA is not that intrepid, the answer is to connect to
the offending node and drop the <SPAN
CLASS="QUOTE"
>"visible"</SPAN
> version of the
trigger using the <ACRONYM
CLASS="ACRONYM"
>SQL</ACRONYM
> <TT
CLASS="COMMAND"
>DROP
TRIGGER</TT
> command.  That should allow the event to proceed.
If the event was <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
>, then the
<SPAN
CLASS="QUOTE"
>"not-so-intrepid"</SPAN
> DBA may need to add the trigger back,
by hand, or, if they are wise, they should consider activating it
using <A
HREF="stmtstoretrigger.html"
>SLONIK STORE TRIGGER</A
>.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9650"
></A
><B
>7.1.9.2. </B
> Behaviour - all the subscriber nodes start to fall
behind the origin, and all the logs on the subscriber nodes have the
following error message repeating in them (when I encountered it,
there was a nice long SQL statement above each entry):</P
><PRE
CLASS="SCREEN"
>ERROR remoteWorkerThread_1: helper 1 finished with error
ERROR remoteWorkerThread_1: SYNC aborted</PRE
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Cause: you have likely issued <TT
CLASS="COMMAND"
>alter
table</TT
> statements directly on the databases instead of using
the slonik <A
HREF="stmtddlscript.html"
>SLONIK EXECUTE SCRIPT</A
> command.</P
><P
>The solution is to rebuild the trigger on the affected table and
fix the entries in <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> by hand.</P
><P
></P
><UL
><LI
><P
> You'll need to identify from either the slon logs, or
the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> database logs exactly which statement it is that is
causing the error.</P
></LI
><LI
><P
> You need to fix the Slony-defined triggers on the
table in question.  This is done with the following procedure.</P
><PRE
CLASS="SCREEN"
>BEGIN;
LOCK TABLE table_name;
SELECT _oxrsorg.altertablerestore(tab_id);--tab_id is _slony_schema.sl_table.tab_id
SELECT _oxrsorg.altertableforreplication(tab_id);--tab_id is _slony_schema.sl_table.tab_id
COMMIT;</PRE
><P
>You then need to find the rows in <A
HREF="table.sl-log-1.html"
>sl_log_1</A
>/<A
HREF="table.sl-log-2.html"
>sl_log_2</A
> that have
bad entries and fix them.  You may want to take down the slon daemons
for all nodes except the master; that way, if you make a mistake, it
won't immediately propagate through to the subscribers.</P
><P
> Here is an example:</P
><PRE
CLASS="SCREEN"
>BEGIN;

LOCK TABLE customer_account;

SELECT _app1.altertablerestore(31);
SELECT _app1.altertableforreplication(31);
COMMIT;

BEGIN;
LOCK TABLE txn_log;

SELECT _app1.altertablerestore(41);
SELECT _app1.altertableforreplication(41);

COMMIT;

--fixing customer_account, which had an attempt to insert a "" into a timestamp with timezone.
BEGIN;

update _app1.sl_log_1 SET log_cmddata = 'balance=''60684.00'' where pkey=''49''' where log_actionseq = '67796036';
update _app1.sl_log_1 SET log_cmddata = 'balance=''60690.00'' where pkey=''49''' where log_actionseq = '67796194';
update _app1.sl_log_1 SET log_cmddata = 'balance=''60684.00'' where pkey=''49''' where log_actionseq = '67795881';
update _app1.sl_log_1 SET log_cmddata = 'balance=''1852.00'' where pkey=''57''' where log_actionseq = '67796403';
update _app1.sl_log_1 SET log_cmddata = 'balance=''87906.00'' where pkey=''8''' where log_actionseq = '68352967';
update _app1.sl_log_1 SET log_cmddata = 'balance=''125180.00'' where pkey=''60''' where log_actionseq = '68386951';
update _app1.sl_log_1 SET log_cmddata = 'balance=''125198.00'' where pkey=''60''' where log_actionseq = '68387055';
update _app1.sl_log_1 SET log_cmddata = 'balance=''125174.00'' where pkey=''60''' where log_actionseq = '68386682';
update _app1.sl_log_1 SET log_cmddata = 'balance=''125186.00'' where pkey=''60''' where log_actionseq = '68386992';
update _app1.sl_log_1 SET log_cmddata = 'balance=''125192.00'' where pkey=''60''' where log_actionseq = '68387029';&#13;</PRE
></LI
></UL
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9673"
></A
><B
>7.1.9.3. </B
> Node #1 was dropped via <A
HREF="stmtdropnode.html"
>SLONIK DROP NODE</A
>, and the <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> one of the
other nodes is repeatedly failing with the error message:</P
><PRE
CLASS="SCREEN"
>ERROR  remoteWorkerThread_3: "begin transaction; set transaction isolation level
 serializable; lock table "_mailermailer".sl_config_lock; select "_mailermailer"
.storeListen_int(2, 1, 3); notify "_mailermailer_Event"; notify "_mailermailer_C
onfirm"; insert into "_mailermailer".sl_event     (ev_origin, ev_seqno, ev_times
tamp,      ev_minxid, ev_maxxid, ev_xip, ev_type , ev_data1, ev_data2, ev_data3
   ) values ('3', '2215', '2005-02-18 10:30:42.529048', '3286814', '3286815', ''
, 'STORE_LISTEN', '2', '1', '3'); insert into "_mailermailer".sl_confirm
(con_origin, con_received, con_seqno, con_timestamp)    values (3, 2, '2215', CU
RRENT_TIMESTAMP); commit transaction;" PGRES_FATAL_ERROR ERROR:  insert or updat
e on table "sl_listen" violates foreign key constraint "sl_listen-sl_path-ref"
DETAIL:  Key (li_provider,li_receiver)=(1,3) is not present in table "sl_path".
DEBUG1 syncThread: thread done</PRE
><P
> Evidently, a <A
HREF="stmtstorelisten.html"
>SLONIK STORE LISTEN</A
> request hadn't
propagated yet before node 1 was dropped.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This points to a case where you'll
need to do <SPAN
CLASS="QUOTE"
>"event surgery"</SPAN
> on one or more of the nodes.
A <TT
CLASS="COMMAND"
>STORE_LISTEN</TT
> event remains outstanding that wants
to add a listen path that <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>cannot</I
></SPAN
> be created
because node 1 and all paths pointing to node 1 have gone away.</P
><P
> Let's assume, for exposition purposes, that the remaining nodes
are #2 and #3, and that the above error is being reported on node
#3.</P
><P
> That implies that the event is stored on node #2, as it
wouldn't be on node #3 if it had not already been processed
successfully.  The easiest way to cope with this situation is to
delete the offending <A
HREF="table.sl-event.html"
>sl_event</A
> entry on node #2.
You'll connect to node #2's database, and search for the
<TT
CLASS="COMMAND"
>STORE_LISTEN</TT
> event:</P
><P
> <TT
CLASS="COMMAND"
> select * from sl_event where ev_type =
'STORE_LISTEN';</TT
></P
><P
> There may be several entries, only some of which need to be
purged. </P
><PRE
CLASS="SCREEN"
> 
-# begin;  -- Don't straight delete them; open a transaction so you can respond to OOPS
BEGIN;
-# delete from sl_event where ev_type = 'STORE_LISTEN' and
-#  (ev_data1 = '1' or ev_data2 = '1' or ev_data3 = '1');
DELETE 3
-# -- Seems OK...
-# commit;
COMMIT</PRE
><P
> The next time the <SPAN
CLASS="APPLICATION"
>slon</SPAN
> for node 3
starts up, it will no longer find the <SPAN
CLASS="QUOTE"
>"offensive"</SPAN
>
<TT
CLASS="COMMAND"
>STORE_LISTEN</TT
> events, and replication can continue.
(You may then run into some other problem where an old stored event is
referring to no-longer-existant configuration...) </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9698"
></A
><B
>7.1.9.4. </B
> I have a database where we have been encountering
the following error message in our application: </P
><PRE
CLASS="SCREEN"
> permission denied for sequence sl_action_seq </PRE
><P
> When we traced it back, it was due to the application calling
<CODE
CLASS="FUNCTION"
> lastval() </CODE
> to capture the most recent sequence
update, which happened to catch the last update to a <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> internal
sequence. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> uses sequences to provide primary key values for log
entries, and therefore this kind of behaviour may (perhaps
regrettably!) be expected.  </P
><P
> Calling <CODE
CLASS="FUNCTION"
>lastval()</CODE
>, to
<SPAN
CLASS="QUOTE"
>"anonymously"</SPAN
> get <SPAN
CLASS="QUOTE"
>"the most recently updated
sequence value"</SPAN
>, rather than using
<CODE
CLASS="FUNCTION"
>currval('sequence_name')</CODE
> is an unsafe thing to do
in general, as anything you might add in that uses DBMS features for
logging, archiving, or replication can throw in an extra sequence
update that you weren't expecting.  </P
><P
> In general, use of <CODE
CLASS="FUNCTION"
>lastval()</CODE
> doesn't seem
terribly safe; using it when <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> (or any similar trigger-based
replication system such as <SPAN
CLASS="APPLICATION"
>Londiste</SPAN
> or
<SPAN
CLASS="APPLICATION"
>Bucardo</SPAN
>) can lead to capturing unexpected
sequence updates. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9718"
></A
><B
>7.1.9.5. </B
> I tried building <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.1 and got the following
error message:
</P><PRE
CLASS="SCREEN"
>configure: error: Headers for libpqserver are not found in the includeserverdir.
   This is the path to postgres.h. Please specify the includeserverdir with
   --with-pgincludeserverdir=&lt;dir&gt;</PRE
><P></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> You are almost certainly running version <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 7.4
or earlier, where server headers are not installed by default if you
just do a <TT
CLASS="COMMAND"
>make install</TT
> of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>.</P
><P
> You need to install server headers when you install <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
via the command <TT
CLASS="COMMAND"
>make install-all-headers</TT
>.&#13;</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9731"
></A
><B
>7.1.9.6. </B
> I'm trying to upgrade to a newer version of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
>
and am running into a problem with <A
HREF="stmtupdatefunctions.html"
>SLONIK UPDATE FUNCTIONS</A
>.  When I run <A
HREF="stmtupdatefunctions.html"
>SLONIK UPDATE FUNCTIONS</A
>, my
<SPAN
CLASS="APPLICATION"
>postmaster</SPAN
> falls over with a Signal 11.
There aren't any seeming errors in the log files, aside from the
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> logs indicating that, yes indeed, the postmaster fell
over.</P
><P
> I connected a debugger to the core file, and it indicates that
it was trying to commit a transaction at the time of the
failure. </P
><P
> By the way I'm on <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.1.[0-3]. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Unfortunately, early releases of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.1 had a
problem where if you redefined a function (such as, say,
<CODE
CLASS="FUNCTION"
>upgradeSchema(text)</CODE
>), and then, in the same
transaction, ran that function, the
<SPAN
CLASS="APPLICATION"
>postmaster</SPAN
> would fall over, and the
transaction would fail to commit.  </P
><P
> The <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
> command <A
HREF="stmtupdatefunctions.html"
>SLONIK UPDATE FUNCTIONS</A
>
functions like that; it, in one transaction, tries to:

<P
></P
></P><UL
><LI
><P
> Load the new functions (from <TT
CLASS="FILENAME"
>slony1_funcs.sql</TT
>), notably including <CODE
CLASS="FUNCTION"
>upgradeSchema(text)</CODE
>.  </P
></LI
><LI
><P
> Run <CODE
CLASS="FUNCTION"
>upgradeSchema(text)</CODE
> to do any necessary upgrades to the database schema. </P
></LI
><LI
><P
> Notify <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes of a change of configuration.</P
></LI
></UL
><P></P
><P
> Unfortunately, on <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.1.0, 8.1.1, 8.1.2, and 8.1.3,
this conflicts with a bug where using and modifying a plpgsql function
in the same transaction leads to a crash. </P
><P
> Several workarounds are available. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The preferred answer would be to upgrade <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> to
8.1.4 or some later version.  Changes between minor versions do not
require rebuilding databases; it should merely require copying a
suitable 8.1.x build into place, and restarting the
<SPAN
CLASS="APPLICATION"
>postmaster</SPAN
> with the new version.  </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> If that is unsuitable, it would be possible to perform
the upgrade via a series of transactions, performing the equivalent of
what <A
HREF="slonik.html"
><SPAN
CLASS="APPLICATION"
>slonik</SPAN
></A
> does <SPAN
CLASS="QUOTE"
>"by hand"</SPAN
>: </P
><P
></P
><UL
><LI
><P
> Take <TT
CLASS="FILENAME"
>slony1_funcs.sql</TT
> and do three replacements within it: </P
><P
></P
><UL
><LI
><P
> Replace <SPAN
CLASS="QUOTE"
>"@CLUSTERNAME@"</SPAN
> with the name of the cluster </P
></LI
><LI
><P
> Replace <SPAN
CLASS="QUOTE"
>"@MODULEVERSION@"</SPAN
> with the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> version string, such as <SPAN
CLASS="QUOTE"
>"1.2.10"</SPAN
> </P
></LI
><LI
><P
> Replace <SPAN
CLASS="QUOTE"
>"@NAMESPACE@"</SPAN
> with the <SPAN
CLASS="QUOTE"
>"double-quoted"</SPAN
> name of the cluster namespace, such as "_MyCluster" </P
></LI
></UL
></LI
><LI
><P
> Load that <SPAN
CLASS="QUOTE"
>"remapped"</SPAN
> set of functions into the database.</P
></LI
><LI
><P
> Run the stored function via <TT
CLASS="COMMAND"
>select <CODE
CLASS="FUNCTION"
>upgradeSchema('1.2.7')</CODE
>; </TT
>, assuming that the previous version of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> in use was version 1.2.7. </P
></LI
><LI
><P
> Restarting all <A
HREF="slon.html"
><SPAN
CLASS="APPLICATION"
>slon</SPAN
></A
> processes would probably be a wise move with this sort of <SPAN
CLASS="QUOTE"
>"surgery."</SPAN
> </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9801"
></A
><B
>7.1.9.7. </B
>Slonik fails - cannot load <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> library -
<TT
CLASS="COMMAND"
>PGRES_FATAL_ERROR load '$libdir/xxid';</TT
></P
><P
> When I run the sample setup script I get an error message similar
to:

<TT
CLASS="COMMAND"
>stdin:64: PGRES_FATAL_ERROR load '$libdir/xxid';  - ERROR:  LOAD:
could not open file '$libdir/xxid': No such file or directory</TT
></P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Evidently, you haven't got the
<TT
CLASS="FILENAME"
>xxid.so</TT
> library in the <TT
CLASS="ENVAR"
>$libdir</TT
>
directory that the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> instance is
using.  Note that the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> components
need to be installed in the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
software installation for <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>each and every one</I
></SPAN
> of
the nodes, not just on the origin node.</P
><P
>This may also point to there being some other mismatch between
the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> binary instance and the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> instance.  If you
compiled <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> yourself, on a machine that may have multiple
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> builds <SPAN
CLASS="QUOTE"
>"lying around,"</SPAN
> it's possible that the
slon or slonik binaries are asking to load something that isn't
actually in the library directory for the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> database cluster
that it's hitting.</P
><P
>Long and short: This points to a need to <SPAN
CLASS="QUOTE"
>"audit"</SPAN
>
what installations of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> and <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> you have in place on the
machine(s).  Unfortunately, just about any mismatch will cause things
not to link up quite right. 
...</P
><P
> Life is simplest if you only have one set of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>
binaries on a given server; in that case, there isn't a <SPAN
CLASS="QUOTE"
>"wrong
place"</SPAN
> in which <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> components might get installed.  If
you have several software installs, you'll have to verify that the
right versions of <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> components are associated with the right
<SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> binaries. </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9833"
></A
><B
>7.1.9.8. </B
>I tried creating a CLUSTER NAME with a "-" in it.
That didn't work.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> uses the same rules for unquoted identifiers
as the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> main parser, so no, you probably shouldn't put a "-"
in your identifier name.</P
><P
> You may be able to defeat this by putting <SPAN
CLASS="QUOTE"
>"quotes"</SPAN
> around
identifier names, but it's still liable to bite you some, so this is
something that is probably not worth working around.</P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9842"
></A
><B
>7.1.9.9. </B
> I have a <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 7.2-based system that I
<SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>really, really</I
></SPAN
> want to use <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to help me
upgrade it to 8.0.  What is involved in getting <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> to work for
that?</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Rod Taylor has reported the following...</P
><P
> This is approximately what you need to do:</P
><P
></P
><UL
><LI
><P
>Take the 7.3 templates and copy them to 7.2 -- or otherwise
        hardcode the version your using to pick up the 7.3 templates </P
></LI
><LI
><P
>Remove all traces of schemas from the code and sql templates. I
        basically changed the "." to an "_". </P
></LI
><LI
><P
> Bunch of work related to the XID datatype and functions. For
        example, Slony creates CASTs for the xid to xxid and back -- but
        7.2 cannot create new casts that way so you need to edit system
        tables by hand. I recall creating an Operator Class and editing
        several functions as well. </P
></LI
><LI
><P
>sl_log_1 will have severe performance problems with any kind of
        data volume. This required a number of index and query changes
        to optimize for 7.2. 7.3 and above are quite a bit smarter in
        terms of optimizations they can apply. </P
></LI
><LI
><P
> Don't bother trying to make sequences work. Do them by hand
        after the upgrade using pg_dump and grep. </P
></LI
></UL
><P
> Of course, now that you have done all of the above, it's not compatible
with standard Slony now. So you either need to implement 7.2 in a less
hackish way, or you can also hack up slony to work without schemas on
newer versions of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> so they can talk to each other.</P
><P
> Almost immediately after getting the DB upgraded from 7.2 to 7.4, we
deinstalled the hacked up Slony (by hand for the most part), and started
a migration from 7.4 to 7.4 on a different machine using the regular
Slony. This was primarily to ensure we didn't keep our system catalogues
which had been manually fiddled with.</P
><P
> All that said, we upgraded a few hundred GB from 7.2 to 7.4
with about 30 minutes actual downtime (versus 48 hours for a dump /
restore cycle) and no data loss.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> That represents a sufficiently ugly set of
<SPAN
CLASS="QUOTE"
>"hackery"</SPAN
> that the developers are exceedingly reluctant
to let it anywhere near to the production code.  If someone were
interested in <SPAN
CLASS="QUOTE"
>"productionizing"</SPAN
> this, it would probably
make sense to do so based on the <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.0 branch, with the express
plan of <SPAN
CLASS="emphasis"
><I
CLASS="EMPHASIS"
>not</I
></SPAN
> trying to keep much in the way of
forwards compatibility or long term maintainability of replicas.</P
><P
> You should only head down this road if you are sufficiently
comfortable with <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> and <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> that you are prepared to hack
pretty heavily with the code.  </P
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9876"
></A
><B
>7.1.9.10. </B
> I created a <SPAN
CLASS="QUOTE"
>"superuser"</SPAN
> account,
<TT
CLASS="COMMAND"
>slony</TT
>, to run replication activities.  As
suggested, I set it up as a superuser, via the following query: 
<TT
CLASS="COMMAND"
>update pg_shadow set usesuper = 't' where usename in ('slony',
'molly', 'dumpy');</TT
>
(that command also deals with other users I set up to run vacuums and
backups).</P
><P
> Unfortunately, I ran into a problem the next time I subscribed
to a new set.</P
><PRE
CLASS="PROGRAMLISTING"
>DEBUG1 copy_set 28661
DEBUG1 remoteWorkerThread_1: connected to provider DB
DEBUG2 remoteWorkerThread_78: forward confirm 1,594436 received by 78
DEBUG2 remoteWorkerThread_1: copy table public.billing_discount
ERROR  remoteWorkerThread_1: "select "_mycluster".setAddTable_int(28661, 51, 'public.billing_discount', 'billing_discount_pkey', 'Table public.billing_discount with candidate primary key billing_discount_pkey'); " PGRES_FATAL_ERROR ERROR:  permission denied for relation pg_class
CONTEXT:  PL/pgSQL function "altertableforreplication" line 23 at select into variables
PL/pgSQL function "setaddtable_int" line 76 at perform
WARN   remoteWorkerThread_1: data copy for set 28661 failed - sleep 60 seconds</PRE
><P
> This continues to fail, over and over, until I restarted the
<SPAN
CLASS="APPLICATION"
>slon</SPAN
> to connect as
<TT
CLASS="COMMAND"
>postgres</TT
> instead.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The problem is fairly self-evident; permission is being
denied on the system table, <TT
CLASS="ENVAR"
>pg_class</TT
>.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> The <SPAN
CLASS="QUOTE"
>"fix"</SPAN
> is thus:</P
><PRE
CLASS="PROGRAMLISTING"
>update pg_shadow set usesuper = 't', usecatupd='t' where usename = 'slony';</PRE
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> In version 8.1 and higher, you may also need the following:</P
><PRE
CLASS="PROGRAMLISTING"
>update pg_authid set rolcatupdate = 't', rolsuper='t' where rolname = 'slony';</PRE
></DIV
></DIV
><DIV
CLASS="QANDAENTRY"
><DIV
CLASS="QUESTION"
><P
><A
NAME="AEN9897"
></A
><B
>7.1.9.11. </B
>Some nodes start consistently falling behind</P
><P
>I have been running <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.2 on a node for a while, and am
seeing system performance suffering.</P
><P
>I'm seeing long running queries of the form:
</P><PRE
CLASS="SCREEN"
>	fetch 100 from LOG;</PRE
><P></P
><P
> By the way, I'm on <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 8.3. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> This has been characteristic of <TT
CLASS="ENVAR"
>pg_listener</TT
> (which is
the table containing <TT
CLASS="COMMAND"
>NOTIFY</TT
> data) having plenty of
dead tuples in it.  That makes <TT
CLASS="COMMAND"
>NOTIFY</TT
> events take a
long time, and causes the affected node to gradually fall further and
further behind.</P
><P
>You quite likely need to do a <TT
CLASS="COMMAND"
>VACUUM FULL</TT
> on
<TT
CLASS="ENVAR"
>pg_listener</TT
>, to vigorously clean it out, and need to vacuum
<TT
CLASS="ENVAR"
>pg_listener</TT
> really frequently.  Once every five minutes would likely
be AOK.</P
><P
> Slon daemons already vacuum a bunch of tables, and
<TT
CLASS="FILENAME"
>cleanup_thread.c</TT
> contains a list of tables that
are frequently vacuumed automatically.  In <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 1.0.2,
<TT
CLASS="ENVAR"
>pg_listener</TT
> is not included.  In 1.0.5 and later, it is regularly
vacuumed, so this should cease to be a direct issue.  In version 1.2,
<TT
CLASS="ENVAR"
>pg_listener</TT
> will only be used when a node is only receiving events
periodically, which means that the issue should mostly go away even in
the presence of evil long running transactions...</P
><P
>There is, however, still a scenario where this will still
<SPAN
CLASS="QUOTE"
>"bite."</SPAN
> Under MVCC, vacuums cannot delete tuples that
were made <SPAN
CLASS="QUOTE"
>"obsolete"</SPAN
> at any time after the start time of
the eldest transaction that is still open.  Long running transactions
will cause trouble, and should be avoided, even on subscriber
nodes.</P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 9.0 introduced a higher performance version
of the LISTEN/NOTIFY feature which eliminated the table <TT
CLASS="ENVAR"
>pg_listener</TT
>
in favour of a memory-based queue.  An upgrade to 9.0 or better would
likely be useful to improve this. </P
></DIV
><DIV
CLASS="ANSWER"
><P
><B
> </B
> Note that <SPAN
CLASS="PRODUCTNAME"
>Slony-I</SPAN
> 2.0 eliminated heavy usage of
LISTEN/NOTIFY, so this particular phenomenon is restricted to versions
older than that. </P
></DIV
></DIV
></DIV
></DIV
></DIV
></DIV
><DIV
CLASS="NAVFOOTER"
><HR
ALIGN="LEFT"
WIDTH="100%"><TABLE
SUMMARY="Footer navigation table"
WIDTH="100%"
BORDER="0"
CELLPADDING="0"
CELLSPACING="0"
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><A
HREF="slony-logshipping.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
><A
HREF="index.html"
ACCESSKEY="H"
>Home</A
></TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
><A
HREF="releasechecklist.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
><SPAN
CLASS="APPLICATION"
>slony_logshipping</SPAN
></TD
><TD
WIDTH="34%"
ALIGN="center"
VALIGN="top"
>&nbsp;</TD
><TD
WIDTH="33%"
ALIGN="right"
VALIGN="top"
>Release Checklist</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>