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// wiredtiger_recovery_unit.h
/**
* Copyright (C) 2014 MongoDB 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 <wiredtiger.h>
#include <memory.h>
#include "mongo/base/owned_pointer_vector.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/record_id.h"
#include "mongo/db/storage/recovery_unit.h"
#include "mongo/db/storage/snapshot_name.h"
#include "mongo/util/concurrency/ticketholder.h"
#include "mongo/util/timer.h"
namespace mongo {
class BSONObjBuilder;
class WiredTigerSession;
class WiredTigerSessionCache;
class WiredTigerRecoveryUnit final : public RecoveryUnit {
public:
WiredTigerRecoveryUnit(WiredTigerSessionCache* sc);
virtual ~WiredTigerRecoveryUnit();
virtual void reportState(BSONObjBuilder* b) const;
void beginUnitOfWork(OperationContext* opCtx) final;
void commitUnitOfWork() final;
void abortUnitOfWork() final;
virtual bool waitUntilDurable();
virtual void registerChange(Change* change);
virtual void abandonSnapshot();
virtual void* writingPtr(void* data, size_t len);
virtual void setRollbackWritesDisabled() {}
virtual SnapshotId getSnapshotId() const;
Status setReadFromMajorityCommittedSnapshot() final;
bool isReadingFromMajorityCommittedSnapshot() const final {
return _readFromMajorityCommittedSnapshot;
}
boost::optional<SnapshotName> getMajorityCommittedSnapshot() const final;
// ---- WT STUFF
WiredTigerSession* getSession(OperationContext* opCtx);
/**
* Returns a session without starting a new WT txn on the session. Will not close any already
* running session.
*/
WiredTigerSession* getSessionNoTxn(OperationContext* opCtx);
WiredTigerSessionCache* getSessionCache() {
return _sessionCache;
}
bool inActiveTxn() const {
return _active;
}
void assertInActiveTxn() const;
bool everStartedWrite() const {
return _everStartedWrite;
}
void setOplogReadTill(const RecordId& id);
RecordId getOplogReadTill() const {
return _oplogReadTill;
}
static WiredTigerRecoveryUnit* get(OperationContext* txn);
static void appendGlobalStats(BSONObjBuilder& b);
/**
* Prepares this RU to be the basis for a named snapshot.
*
* Begins a WT transaction, and invariants if we are already in one.
* Bans being in a WriteUnitOfWork until the next call to abandonSnapshot().
*/
void prepareForCreateSnapshot(OperationContext* opCtx);
private:
void _abort();
void _commit();
void _ensureSession();
void _txnClose(bool commit);
void _txnOpen(OperationContext* opCtx);
WiredTigerSessionCache* _sessionCache; // not owned
WiredTigerSession* _session; // owned, but from pool
bool _areWriteUnitOfWorksBanned = false;
bool _inUnitOfWork;
bool _active;
uint64_t _myTransactionCount;
bool _everStartedWrite;
Timer _timer;
RecordId _oplogReadTill;
bool _readFromMajorityCommittedSnapshot = false;
SnapshotName _majorityCommittedSnapshot = SnapshotName::min();
typedef OwnedPointerVector<Change> Changes;
Changes _changes;
};
/**
* This is a smart pointer that wraps a WT_CURSOR and knows how to obtain and get from pool.
*/
class WiredTigerCursor {
public:
WiredTigerCursor(const std::string& uri,
uint64_t tableID,
bool forRecordStore,
OperationContext* txn);
~WiredTigerCursor();
WT_CURSOR* get() const {
// TODO(SERVER-16816): assertInActiveTxn();
return _cursor;
}
WT_CURSOR* operator->() const {
return get();
}
WiredTigerSession* getSession() {
return _session;
}
WT_SESSION* getWTSession();
void reset();
void assertInActiveTxn() const {
_ru->assertInActiveTxn();
}
private:
uint64_t _tableID;
WiredTigerRecoveryUnit* _ru; // not owned
WiredTigerSession* _session;
WT_CURSOR* _cursor; // owned, but pulled
};
}
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