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// oplog.h - writing to and reading from oplog
* 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
* 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 <>.
local.oplog.$main is the default
#pragma once
#include "pdfile.h"
#include "db.h"
#include "dbhelpers.h"
#include "clientcursor.h"
#include "../client/dbclient.h"
#include "../util/optime.h"
#include "../util/timer.h"
namespace mongo {
void createOplog();
void _logOpObjRS(const BSONObj& op);
/** Write operation to the log (local.oplog.$main)
@param opstr
"i" insert
"u" update
"d" delete
"c" db cmd
"n" no-op
"db" declares presence of a database (ns is set to the db name + '.')
See _logOp() in oplog.cpp for more details.
void logOp(const char *opstr, const char *ns, const BSONObj& obj, BSONObj *patt = 0, bool *b = 0);
void logKeepalive();
/** puts obj in the oplog as a comment (a no-op). Just for diags.
convention is
{ msg : "text", ... }
void logOpComment(const BSONObj& obj);
void oplogCheckCloseDatabase( Database * db );
extern int __findingStartInitialTimeout; // configurable for testing
class QueryPlan;
/** Implements an optimized procedure for finding the first op in the oplog. */
class FindingStartCursor {
* The cursor will attempt to find the first op in the oplog matching the
* 'ts' field of the qp's query.
FindingStartCursor( const QueryPlan & qp );
/** @return true if the first matching op in the oplog has been found. */
bool done() const { return !_findingStart; }
/** @return cursor pointing to the first matching op, if done(). */
shared_ptr<Cursor> cursor() { verify( 14835, done() ); return _c; }
/** Iterate the cursor, to continue trying to find matching op. */
void next();
/** Yield cursor, if not done(). */
bool prepareToYield() {
if ( _findingStartCursor ) {
return _findingStartCursor->prepareToYield( _yieldData );
return false;
/** Recover from cursor yield. */
void recoverFromYield() {
if ( _findingStartCursor ) {
if ( !ClientCursor::recoverFromYield( _yieldData ) ) {
_findingStartCursor.reset( 0 );
msgassertedNoTrace( 15889, "FindingStartCursor::recoverFromYield() failed to recover" );
enum FindingStartMode { Initial, FindExtent, InExtent };
const QueryPlan &_qp;
bool _findingStart;
FindingStartMode _findingStartMode;
auto_ptr< CoveredIndexMatcher > _matcher;
Timer _findingStartTimer;
ClientCursor::CleanupPointer _findingStartCursor;
shared_ptr<Cursor> _c;
ClientCursor::YieldData _yieldData;
DiskLoc extentFirstLoc( const DiskLoc &rec );
DiskLoc prevExtentFirstLoc( const DiskLoc &rec );
void createClientCursor( const DiskLoc &startLoc = DiskLoc() );
void destroyClientCursor() {
_findingStartCursor.reset( 0 );
void init();
bool firstDocMatchesOrEmpty() const;
void pretouchOperation(const BSONObj& op);
void pretouchN(vector<BSONObj>&, unsigned a, unsigned b);
* take an op and apply locally
* used for applying from an oplog
* @param fromRepl really from replication or for testing/internal/command/etc...
* Returns if the op was an update that could not be applied (true on failure)
bool applyOperation_inlock(const BSONObj& op , bool fromRepl = true );
* If applyOperation_inlock should be called again after an update fails.
bool shouldRetry(const BSONObj& op , const string& hn);
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