/usr/share/gocode/src/github.com/syndtr/goleveldb/leveldb/table.go is in golang-github-syndtr-goleveldb-dev 0.0~git20170725.0.b89cc31-2.
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 | // Copyright (c) 2012, Suryandaru Triandana <syndtr@gmail.com>
// All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
package leveldb
import (
"fmt"
"sort"
"sync/atomic"
"github.com/syndtr/goleveldb/leveldb/cache"
"github.com/syndtr/goleveldb/leveldb/iterator"
"github.com/syndtr/goleveldb/leveldb/opt"
"github.com/syndtr/goleveldb/leveldb/storage"
"github.com/syndtr/goleveldb/leveldb/table"
"github.com/syndtr/goleveldb/leveldb/util"
)
// tFile holds basic information about a table.
type tFile struct {
fd storage.FileDesc
seekLeft int32
size int64
imin, imax internalKey
}
// Returns true if given key is after largest key of this table.
func (t *tFile) after(icmp *iComparer, ukey []byte) bool {
return ukey != nil && icmp.uCompare(ukey, t.imax.ukey()) > 0
}
// Returns true if given key is before smallest key of this table.
func (t *tFile) before(icmp *iComparer, ukey []byte) bool {
return ukey != nil && icmp.uCompare(ukey, t.imin.ukey()) < 0
}
// Returns true if given key range overlaps with this table key range.
func (t *tFile) overlaps(icmp *iComparer, umin, umax []byte) bool {
return !t.after(icmp, umin) && !t.before(icmp, umax)
}
// Cosumes one seek and return current seeks left.
func (t *tFile) consumeSeek() int32 {
return atomic.AddInt32(&t.seekLeft, -1)
}
// Creates new tFile.
func newTableFile(fd storage.FileDesc, size int64, imin, imax internalKey) *tFile {
f := &tFile{
fd: fd,
size: size,
imin: imin,
imax: imax,
}
// We arrange to automatically compact this file after
// a certain number of seeks. Let's assume:
// (1) One seek costs 10ms
// (2) Writing or reading 1MB costs 10ms (100MB/s)
// (3) A compaction of 1MB does 25MB of IO:
// 1MB read from this level
// 10-12MB read from next level (boundaries may be misaligned)
// 10-12MB written to next level
// This implies that 25 seeks cost the same as the compaction
// of 1MB of data. I.e., one seek costs approximately the
// same as the compaction of 40KB of data. We are a little
// conservative and allow approximately one seek for every 16KB
// of data before triggering a compaction.
f.seekLeft = int32(size / 16384)
if f.seekLeft < 100 {
f.seekLeft = 100
}
return f
}
func tableFileFromRecord(r atRecord) *tFile {
return newTableFile(storage.FileDesc{storage.TypeTable, r.num}, r.size, r.imin, r.imax)
}
// tFiles hold multiple tFile.
type tFiles []*tFile
func (tf tFiles) Len() int { return len(tf) }
func (tf tFiles) Swap(i, j int) { tf[i], tf[j] = tf[j], tf[i] }
func (tf tFiles) nums() string {
x := "[ "
for i, f := range tf {
if i != 0 {
x += ", "
}
x += fmt.Sprint(f.fd.Num)
}
x += " ]"
return x
}
// Returns true if i smallest key is less than j.
// This used for sort by key in ascending order.
func (tf tFiles) lessByKey(icmp *iComparer, i, j int) bool {
a, b := tf[i], tf[j]
n := icmp.Compare(a.imin, b.imin)
if n == 0 {
return a.fd.Num < b.fd.Num
}
return n < 0
}
// Returns true if i file number is greater than j.
// This used for sort by file number in descending order.
func (tf tFiles) lessByNum(i, j int) bool {
return tf[i].fd.Num > tf[j].fd.Num
}
// Sorts tables by key in ascending order.
func (tf tFiles) sortByKey(icmp *iComparer) {
sort.Sort(&tFilesSortByKey{tFiles: tf, icmp: icmp})
}
// Sorts tables by file number in descending order.
func (tf tFiles) sortByNum() {
sort.Sort(&tFilesSortByNum{tFiles: tf})
}
// Returns sum of all tables size.
func (tf tFiles) size() (sum int64) {
for _, t := range tf {
sum += t.size
}
return sum
}
// Searches smallest index of tables whose its smallest
// key is after or equal with given key.
func (tf tFiles) searchMin(icmp *iComparer, ikey internalKey) int {
return sort.Search(len(tf), func(i int) bool {
return icmp.Compare(tf[i].imin, ikey) >= 0
})
}
// Searches smallest index of tables whose its largest
// key is after or equal with given key.
func (tf tFiles) searchMax(icmp *iComparer, ikey internalKey) int {
return sort.Search(len(tf), func(i int) bool {
return icmp.Compare(tf[i].imax, ikey) >= 0
})
}
// Returns true if given key range overlaps with one or more
// tables key range. If unsorted is true then binary search will not be used.
func (tf tFiles) overlaps(icmp *iComparer, umin, umax []byte, unsorted bool) bool {
if unsorted {
// Check against all files.
for _, t := range tf {
if t.overlaps(icmp, umin, umax) {
return true
}
}
return false
}
i := 0
if len(umin) > 0 {
// Find the earliest possible internal key for min.
i = tf.searchMax(icmp, makeInternalKey(nil, umin, keyMaxSeq, keyTypeSeek))
}
if i >= len(tf) {
// Beginning of range is after all files, so no overlap.
return false
}
return !tf[i].before(icmp, umax)
}
// Returns tables whose its key range overlaps with given key range.
// Range will be expanded if ukey found hop across tables.
// If overlapped is true then the search will be restarted if umax
// expanded.
// The dst content will be overwritten.
func (tf tFiles) getOverlaps(dst tFiles, icmp *iComparer, umin, umax []byte, overlapped bool) tFiles {
dst = dst[:0]
for i := 0; i < len(tf); {
t := tf[i]
if t.overlaps(icmp, umin, umax) {
if umin != nil && icmp.uCompare(t.imin.ukey(), umin) < 0 {
umin = t.imin.ukey()
dst = dst[:0]
i = 0
continue
} else if umax != nil && icmp.uCompare(t.imax.ukey(), umax) > 0 {
umax = t.imax.ukey()
// Restart search if it is overlapped.
if overlapped {
dst = dst[:0]
i = 0
continue
}
}
dst = append(dst, t)
}
i++
}
return dst
}
// Returns tables key range.
func (tf tFiles) getRange(icmp *iComparer) (imin, imax internalKey) {
for i, t := range tf {
if i == 0 {
imin, imax = t.imin, t.imax
continue
}
if icmp.Compare(t.imin, imin) < 0 {
imin = t.imin
}
if icmp.Compare(t.imax, imax) > 0 {
imax = t.imax
}
}
return
}
// Creates iterator index from tables.
func (tf tFiles) newIndexIterator(tops *tOps, icmp *iComparer, slice *util.Range, ro *opt.ReadOptions) iterator.IteratorIndexer {
if slice != nil {
var start, limit int
if slice.Start != nil {
start = tf.searchMax(icmp, internalKey(slice.Start))
}
if slice.Limit != nil {
limit = tf.searchMin(icmp, internalKey(slice.Limit))
} else {
limit = tf.Len()
}
tf = tf[start:limit]
}
return iterator.NewArrayIndexer(&tFilesArrayIndexer{
tFiles: tf,
tops: tops,
icmp: icmp,
slice: slice,
ro: ro,
})
}
// Tables iterator index.
type tFilesArrayIndexer struct {
tFiles
tops *tOps
icmp *iComparer
slice *util.Range
ro *opt.ReadOptions
}
func (a *tFilesArrayIndexer) Search(key []byte) int {
return a.searchMax(a.icmp, internalKey(key))
}
func (a *tFilesArrayIndexer) Get(i int) iterator.Iterator {
if i == 0 || i == a.Len()-1 {
return a.tops.newIterator(a.tFiles[i], a.slice, a.ro)
}
return a.tops.newIterator(a.tFiles[i], nil, a.ro)
}
// Helper type for sortByKey.
type tFilesSortByKey struct {
tFiles
icmp *iComparer
}
func (x *tFilesSortByKey) Less(i, j int) bool {
return x.lessByKey(x.icmp, i, j)
}
// Helper type for sortByNum.
type tFilesSortByNum struct {
tFiles
}
func (x *tFilesSortByNum) Less(i, j int) bool {
return x.lessByNum(i, j)
}
// Table operations.
type tOps struct {
s *session
noSync bool
cache *cache.Cache
bcache *cache.Cache
bpool *util.BufferPool
}
// Creates an empty table and returns table writer.
func (t *tOps) create() (*tWriter, error) {
fd := storage.FileDesc{storage.TypeTable, t.s.allocFileNum()}
fw, err := t.s.stor.Create(fd)
if err != nil {
return nil, err
}
return &tWriter{
t: t,
fd: fd,
w: fw,
tw: table.NewWriter(fw, t.s.o.Options),
}, nil
}
// Builds table from src iterator.
func (t *tOps) createFrom(src iterator.Iterator) (f *tFile, n int, err error) {
w, err := t.create()
if err != nil {
return
}
defer func() {
if err != nil {
w.drop()
}
}()
for src.Next() {
err = w.append(src.Key(), src.Value())
if err != nil {
return
}
}
err = src.Error()
if err != nil {
return
}
n = w.tw.EntriesLen()
f, err = w.finish()
return
}
// Opens table. It returns a cache handle, which should
// be released after use.
func (t *tOps) open(f *tFile) (ch *cache.Handle, err error) {
ch = t.cache.Get(0, uint64(f.fd.Num), func() (size int, value cache.Value) {
var r storage.Reader
r, err = t.s.stor.Open(f.fd)
if err != nil {
return 0, nil
}
var bcache *cache.NamespaceGetter
if t.bcache != nil {
bcache = &cache.NamespaceGetter{Cache: t.bcache, NS: uint64(f.fd.Num)}
}
var tr *table.Reader
tr, err = table.NewReader(r, f.size, f.fd, bcache, t.bpool, t.s.o.Options)
if err != nil {
r.Close()
return 0, nil
}
return 1, tr
})
if ch == nil && err == nil {
err = ErrClosed
}
return
}
// Finds key/value pair whose key is greater than or equal to the
// given key.
func (t *tOps) find(f *tFile, key []byte, ro *opt.ReadOptions) (rkey, rvalue []byte, err error) {
ch, err := t.open(f)
if err != nil {
return nil, nil, err
}
defer ch.Release()
return ch.Value().(*table.Reader).Find(key, true, ro)
}
// Finds key that is greater than or equal to the given key.
func (t *tOps) findKey(f *tFile, key []byte, ro *opt.ReadOptions) (rkey []byte, err error) {
ch, err := t.open(f)
if err != nil {
return nil, err
}
defer ch.Release()
return ch.Value().(*table.Reader).FindKey(key, true, ro)
}
// Returns approximate offset of the given key.
func (t *tOps) offsetOf(f *tFile, key []byte) (offset int64, err error) {
ch, err := t.open(f)
if err != nil {
return
}
defer ch.Release()
return ch.Value().(*table.Reader).OffsetOf(key)
}
// Creates an iterator from the given table.
func (t *tOps) newIterator(f *tFile, slice *util.Range, ro *opt.ReadOptions) iterator.Iterator {
ch, err := t.open(f)
if err != nil {
return iterator.NewEmptyIterator(err)
}
iter := ch.Value().(*table.Reader).NewIterator(slice, ro)
iter.SetReleaser(ch)
return iter
}
// Removes table from persistent storage. It waits until
// no one use the the table.
func (t *tOps) remove(f *tFile) {
t.cache.Delete(0, uint64(f.fd.Num), func() {
if err := t.s.stor.Remove(f.fd); err != nil {
t.s.logf("table@remove removing @%d %q", f.fd.Num, err)
} else {
t.s.logf("table@remove removed @%d", f.fd.Num)
}
if t.bcache != nil {
t.bcache.EvictNS(uint64(f.fd.Num))
}
})
}
// Closes the table ops instance. It will close all tables,
// regadless still used or not.
func (t *tOps) close() {
t.bpool.Close()
t.cache.Close()
if t.bcache != nil {
t.bcache.CloseWeak()
}
}
// Creates new initialized table ops instance.
func newTableOps(s *session) *tOps {
var (
cacher cache.Cacher
bcache *cache.Cache
bpool *util.BufferPool
)
if s.o.GetOpenFilesCacheCapacity() > 0 {
cacher = cache.NewLRU(s.o.GetOpenFilesCacheCapacity())
}
if !s.o.GetDisableBlockCache() {
var bcacher cache.Cacher
if s.o.GetBlockCacheCapacity() > 0 {
bcacher = cache.NewLRU(s.o.GetBlockCacheCapacity())
}
bcache = cache.NewCache(bcacher)
}
if !s.o.GetDisableBufferPool() {
bpool = util.NewBufferPool(s.o.GetBlockSize() + 5)
}
return &tOps{
s: s,
noSync: s.o.GetNoSync(),
cache: cache.NewCache(cacher),
bcache: bcache,
bpool: bpool,
}
}
// tWriter wraps the table writer. It keep track of file descriptor
// and added key range.
type tWriter struct {
t *tOps
fd storage.FileDesc
w storage.Writer
tw *table.Writer
first, last []byte
}
// Append key/value pair to the table.
func (w *tWriter) append(key, value []byte) error {
if w.first == nil {
w.first = append([]byte{}, key...)
}
w.last = append(w.last[:0], key...)
return w.tw.Append(key, value)
}
// Returns true if the table is empty.
func (w *tWriter) empty() bool {
return w.first == nil
}
// Closes the storage.Writer.
func (w *tWriter) close() {
if w.w != nil {
w.w.Close()
w.w = nil
}
}
// Finalizes the table and returns table file.
func (w *tWriter) finish() (f *tFile, err error) {
defer w.close()
err = w.tw.Close()
if err != nil {
return
}
if !w.t.noSync {
err = w.w.Sync()
if err != nil {
return
}
}
f = newTableFile(w.fd, int64(w.tw.BytesLen()), internalKey(w.first), internalKey(w.last))
return
}
// Drops the table.
func (w *tWriter) drop() {
w.close()
w.t.s.stor.Remove(w.fd)
w.t.s.reuseFileNum(w.fd.Num)
w.tw = nil
w.first = nil
w.last = nil
}
|