/usr/include/mongo/db/repl/bgsync.h is in mongodb-dev 1:2.4.9-1ubuntu2.
This file is owned by root:root, with mode 0o644.
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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 | /**
* Copyright (C) 2012 10gen Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License, version 3,
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#pragma once
#include <boost/thread/mutex.hpp>
#include "mongo/util/queue.h"
#include "mongo/db/oplogreader.h"
#include "mongo/db/repl/rs.h"
#include "mongo/db/jsobj.h"
namespace mongo {
namespace replset {
// This interface exists to facilitate easier testing;
// the test infrastructure implements these functions with stubs.
class BackgroundSyncInterface {
public:
virtual ~BackgroundSyncInterface();
// Gets the head of the buffer, but does not remove it.
// Returns true if an element was present at the head;
// false if the queue was empty.
virtual bool peek(BSONObj* op) = 0;
// Deletes objects in the queue;
// called by sync thread after it has applied an op
virtual void consume() = 0;
// Returns the member we're currently syncing from (or NULL)
virtual const Member* getSyncTarget() = 0;
// wait up to 1 second for more ops to appear
virtual void waitForMore() = 0;
};
/**
* notifierThread() uses lastOpTimeWritten to inform the sync target where this member is
* currently synced to.
*
* Lock order:
* 1. rslock
* 2. rwlock
* 3. BackgroundSync::_mutex
*/
class BackgroundSync : public BackgroundSyncInterface {
static BackgroundSync *s_instance;
// protects creation of s_instance
static boost::mutex s_mutex;
// _mutex protects all of the class variables
boost::mutex _mutex;
// Production thread
BlockingQueue<BSONObj> _buffer;
OpTime _lastOpTimeFetched;
long long _lastH;
// if produce thread should be running
bool _pause;
bool _appliedBuffer;
bool _assumingPrimary;
boost::condition _condvar;
const Member* _currentSyncTarget;
// Notifier thread
// used to wait until another op has been replicated
boost::condition_variable _lastOpCond;
boost::mutex _lastOpMutex;
const Member* _oplogMarkerTarget;
OplogReader _oplogMarker; // not locked, only used by notifier thread
OpTime _consumedOpTime; // not locked, only used by notifier thread
BackgroundSync();
BackgroundSync(const BackgroundSync& s);
BackgroundSync operator=(const BackgroundSync& s);
// Production thread
void _producerThread();
// Adds elements to the list, up to maxSize.
void produce();
// Check if rollback is necessary
bool isRollbackRequired(OplogReader& r);
void getOplogReader(OplogReader& r);
// Evaluate if the current sync target is still good
bool shouldChangeSyncTarget();
// check lastOpTimeWritten against the remote's earliest op, filling in remoteOldestOp.
bool isStale(OplogReader& r, BSONObj& remoteOldestOp);
// stop syncing when this becomes a primary
void stop();
// restart syncing
void start();
// Tracker thread
// tells the sync target where this member is synced to
void markOplog();
bool hasCursor();
bool isAssumingPrimary();
public:
static BackgroundSync* get();
static void shutdown();
static void notify();
virtual ~BackgroundSync() {}
// starts the producer thread
void producerThread();
// starts the sync target notifying thread
void notifierThread();
// Interface implementation
virtual bool peek(BSONObj* op);
virtual void consume();
virtual const Member* getSyncTarget();
virtual void waitForMore();
// For monitoring
BSONObj getCounters();
// Wait for replication to finish and buffer to be applied so that the member can become
// primary.
void stopReplicationAndFlushBuffer();
};
} // namespace replset
} // namespace mongo
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