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/**
* Copyright (C) 2008 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/>.
*
* As a special exception, the copyright holders give permission to link the
* code of portions of this program with the OpenSSL library under certain
* conditions as described in each individual source file and distribute
* linked combinations including the program with the OpenSSL library. You
* must comply with the GNU Affero General Public License in all respects for
* all of the code used other than as permitted herein. If you modify file(s)
* with this exception, you may extend this exception to your version of the
* file(s), but you are not obligated to do so. If you do not wish to do so,
* delete this exception statement from your version. If you delete this
* exception statement from all source files in the program, then also delete
* it in the license file.
*/
#pragma once
#include "mongo/db/repl/oplogreader.h"
/* replication data overview
at the slave:
local.sources { host: ..., source: ..., only: ..., syncedTo: ..., localLogTs: ..., dbsNextPass: { ... }, incompleteCloneDbs: { ... } }
at the master:
local.oplog.$<source>
*/
namespace mongo {
class Database;
class OldThreadPool;
class OperationContext;
namespace repl {
// Main entry point for master/slave at startup time.
void startMasterSlave(OperationContext* txn);
// externed for use with resync.cpp
extern volatile int relinquishSyncingSome;
extern volatile int syncing;
extern const char* replInfo;
/* A replication exception */
class SyncException : public DBException {
public:
SyncException() : DBException("sync exception", 10001) {}
};
/* A Source is a source from which we can pull (replicate) data.
stored in collection local.sources.
Can be a group of things to replicate for several databases.
{ host: ..., source: ..., only: ..., syncedTo: ..., dbsNextPass: { ... }, incompleteCloneDbs: { ... } }
'source' defaults to 'main'; support for multiple source names is
not done (always use main for now).
*/
class ReplSource {
std::shared_ptr<OldThreadPool> tp;
void resync(OperationContext* txn, const std::string& dbName);
/** @param alreadyLocked caller already put us in write lock if true */
void _sync_pullOpLog_applyOperation(OperationContext* txn, BSONObj& op, bool alreadyLocked);
/* pull some operations from the master's oplog, and apply them.
calls sync_pullOpLog_applyOperation
*/
int _sync_pullOpLog(OperationContext* txn, int& nApplied);
/* we only clone one database per pass, even if a lot need done. This helps us
avoid overflowing the master's transaction log by doing too much work before going
back to read more transactions. (Imagine a scenario of slave startup where we try to
clone 100 databases in one pass.)
*/
std::set<std::string> addDbNextPass;
std::set<std::string> incompleteCloneDbs;
/// TODO(spencer): Remove this once the LegacyReplicationCoordinator is gone.
BSONObj _me;
void resyncDrop(OperationContext* txn, const std::string& db);
// call without the db mutex
void syncToTailOfRemoteLog();
std::string ns() const {
return std::string("local.oplog.$") + sourceName();
}
unsigned _sleepAdviceTime;
/**
* If 'db' is a new database and its name would conflict with that of
* an existing database, synchronize these database names with the
* master.
* @return true iff an op with the specified ns may be applied.
*/
bool handleDuplicateDbName(OperationContext* txn,
const BSONObj& op,
const char* ns,
const char* db);
// populates _me so that it can be passed to oplogreader for handshakes
/// TODO(spencer): Remove this function once the LegacyReplicationCoordinator is gone.
void ensureMe(OperationContext* txn);
void forceResync(OperationContext* txn, const char* requester);
bool _connect(OplogReader* reader, const HostAndPort& host, const OID& myRID);
public:
OplogReader oplogReader;
void applyCommand(OperationContext* txn, const BSONObj& op);
void applyOperation(OperationContext* txn, Database* db, const BSONObj& op);
std::string hostName; // ip addr or hostname plus optionally, ":<port>"
std::string _sourceName; // a logical source name.
std::string sourceName() const {
return _sourceName.empty() ? "main" : _sourceName;
}
std::string
only; // only a certain db. note that in the sources collection, this may not be changed once you start replicating.
/* the last time point we have already synced up to (in the remote/master's oplog). */
Timestamp syncedTo;
int nClonedThisPass;
typedef std::vector<std::shared_ptr<ReplSource>> SourceVector;
static void loadAll(OperationContext* txn, SourceVector&);
explicit ReplSource(OperationContext* txn, BSONObj);
// This is not the constructor you are looking for. Always prefer the version that takes
// a BSONObj. This is public only as a hack so that the ReplicationCoordinator can find
// out the process's RID in master/slave setups.
ReplSource(OperationContext* txn);
/* -1 = error */
int sync(OperationContext* txn, int& nApplied);
void save(OperationContext* txn); // write ourself to local.sources
// make a jsobj from our member fields of the form
// { host: ..., source: ..., syncedTo: ... }
BSONObj jsobj();
bool operator==(const ReplSource& r) const {
return hostName == r.hostName && sourceName() == r.sourceName();
}
std::string toString() const {
return sourceName() + "@" + hostName;
}
bool haveMoreDbsToSync() const {
return !addDbNextPass.empty();
}
int sleepAdvice() const {
if (!_sleepAdviceTime)
return 0;
int wait = _sleepAdviceTime - unsigned(time(0));
return wait > 0 ? wait : 0;
}
static bool throttledForceResyncDead(OperationContext* txn, const char* requester);
static void forceResyncDead(OperationContext* txn, const char* requester);
};
/**
* Helper class used to set and query an ignore state for a named database.
* The ignore state will expire after a specified Timestamp.
*/
class DatabaseIgnorer {
public:
/** Indicate that operations for 'db' should be ignored until after 'futureOplogTime' */
void doIgnoreUntilAfter(const std::string& db, const Timestamp& futureOplogTime);
/**
* Query ignore state of 'db'; if 'currentOplogTime' is after the ignore
* limit, the ignore state will be cleared.
*/
bool ignoreAt(const std::string& db, const Timestamp& currentOplogTime);
private:
std::map<std::string, Timestamp> _ignores;
};
} // namespace repl
} // namespace mongo
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