This cache implements a shared pool of WiredTiger sessions with the goal to amortize the cost of session creation and destruction over multiple uses. More...

#include <wiredtiger_session_cache.h>

Detailed Description

This cache implements a shared pool of WiredTiger sessions with the goal to amortize the cost of session creation and destruction over multiple uses.

Classes
class	WiredTigerSessionDeleter
	This deleter automatically releases WiredTigerSession objects when no longer needed. More...

Public Member Functions
	WiredTigerSessionCache (WiredTigerKVEngine *engine)

	WiredTigerSessionCache (WT_CONNECTION *conn)

	~WiredTigerSessionCache ()

std::unique_ptr< WiredTigerSession, WiredTigerSessionDeleter >	getSession ()
	Returns a smart pointer to a previously released session for reuse, or creates a new session. More...

void	closeAll ()
	Free all cached sessions and ensures that previously acquired sessions will be freed on release. More...

void	closeCursorsForQueuedDrops ()
	Closes cached cursors for tables that are queued to be dropped. More...

void	closeAllCursors (const std::string &uri)
	Closes all cached cursors matching the uri. More...

void	shuttingDown ()
	Transitions the cache to shutting down mode. More...

bool	isEphemeral ()

void	waitUntilDurable (bool forceCheckpoint, bool stableCheckpoint)
	Waits until all commits that happened before this call are durable, either by flushing the log or forcing a checkpoint if forceCheckpoint is true or the journal is disabled. More...

void	waitUntilPreparedUnitOfWorkCommitsOrAborts (OperationContext *opCtx)
	Waits until a prepared unit of work has ended (either been commited or aborted). More...

void	notifyPreparedUnitOfWorkHasCommittedOrAborted ()
	Notifies waiters that the caller's perpared unit of work has ended (either committed or aborted). More...

WT_CONNECTION *	conn () const

WiredTigerSnapshotManager &	snapshotManager ()

const WiredTigerSnapshotManager &	snapshotManager () const

void	setJournalListener (JournalListener *jl)

uint64_t	getCursorEpoch () const

WiredTigerKVEngine *	getKVEngine () const

Static Public Member Functions
static bool	isEngineCachingCursors ()
	Indicates that WiredTiger should be configured to cache cursors. More...

Private Types
typedef std::vector< WiredTigerSession * >	SessionCache

Private Member Functions
void	releaseSession (WiredTigerSession *session)
	Returns a session to the cache for later reuse. More...

Private Attributes
WiredTigerKVEngine *	_engine

WT_CONNECTION *	_conn

WiredTigerSnapshotManager	_snapshotManager

AtomicUInt32	_shuttingDown

stdx::mutex	_cacheLock

SessionCache	_sessions

AtomicUInt64	_epoch

AtomicUInt64	_cursorEpoch

AtomicUInt32	_lastSyncTime

stdx::mutex	_lastSyncMutex

stdx::mutex	_prepareCommittedOrAbortedMutex

stdx::condition_variable	_prepareCommittedOrAbortedCond

std::uint64_t	_lastCommitOrAbortCounter

stdx::mutex	_journalListenerMutex

JournalListener *	_journalListener = &NoOpJournalListener::instance

WT_SESSION *	_waitUntilDurableSession = nullptr

Static Private Attributes
static const uint32_t	kShuttingDownMask = 1 << 31

Member Typedef Documentation

◆ SessionCache

typedef std::vector<WiredTigerSession*> mongo::WiredTigerSessionCache::SessionCache

private

Constructor & Destructor Documentation

◆ WiredTigerSessionCache() [1/2]

mongo::WiredTigerSessionCache::WiredTigerSessionCache ( WiredTigerKVEngine * engine )

◆ WiredTigerSessionCache() [2/2]

mongo::WiredTigerSessionCache::WiredTigerSessionCache ( WT_CONNECTION * conn )

◆ ~WiredTigerSessionCache()

mongo::WiredTigerSessionCache::~WiredTigerSessionCache ( )

Member Function Documentation

◆ closeAll()

void mongo::WiredTigerSessionCache::closeAll ( )

Free all cached sessions and ensures that previously acquired sessions will be freed on release.

◆ closeAllCursors()

void mongo::WiredTigerSessionCache::closeAllCursors ( const std::string & uri )

Closes all cached cursors matching the uri.

If the uri is empty, all cached cursors are closed.

◆ closeCursorsForQueuedDrops()

void mongo::WiredTigerSessionCache::closeCursorsForQueuedDrops ( )

Closes cached cursors for tables that are queued to be dropped.

◆ conn()

WT_CONNECTION* mongo::WiredTigerSessionCache::conn ( ) const

inline

◆ getCursorEpoch()

uint64_t mongo::WiredTigerSessionCache::getCursorEpoch ( ) const

inline

◆ getKVEngine()

WiredTigerKVEngine* mongo::WiredTigerSessionCache::getKVEngine ( ) const

inline

◆ getSession()

UniqueWiredTigerSession mongo::WiredTigerSessionCache::getSession ( )

Returns a smart pointer to a previously released session for reuse, or creates a new session.

This method must only be called while holding the global lock to avoid races with shuttingDown, but otherwise is thread safe.

◆ isEngineCachingCursors()

bool mongo::WiredTigerSessionCache::isEngineCachingCursors ( )

static

Indicates that WiredTiger should be configured to cache cursors.

◆ isEphemeral()

bool mongo::WiredTigerSessionCache::isEphemeral ( )

◆ notifyPreparedUnitOfWorkHasCommittedOrAborted()

void mongo::WiredTigerSessionCache::notifyPreparedUnitOfWorkHasCommittedOrAborted ( )

Notifies waiters that the caller's perpared unit of work has ended (either committed or aborted).

◆ releaseSession()

void mongo::WiredTigerSessionCache::releaseSession ( WiredTigerSession * session )

private

Returns a session to the cache for later reuse.

If closeAll was called between getting this session and releasing it, the session is directly released. This method is thread safe.

◆ setJournalListener()

void mongo::WiredTigerSessionCache::setJournalListener ( JournalListener * jl )

◆ shuttingDown()

void mongo::WiredTigerSessionCache::shuttingDown ( )

Transitions the cache to shutting down mode.

Any already released sessions are freed and any sessions released subsequently are leaked. Must be called while holding the global lock in exclusive mode to avoid races with getSession.

◆ snapshotManager() [1/2]

WiredTigerSnapshotManager& mongo::WiredTigerSessionCache::snapshotManager ( )

inline

◆ snapshotManager() [2/2]

const WiredTigerSnapshotManager& mongo::WiredTigerSessionCache::snapshotManager ( ) const

inline

◆ waitUntilDurable()

void mongo::WiredTigerSessionCache::waitUntilDurable	(	bool	forceCheckpoint,
		bool	stableCheckpoint
	)

Waits until all commits that happened before this call are durable, either by flushing the log or forcing a checkpoint if forceCheckpoint is true or the journal is disabled.

Uses a temporary session. Safe to call without any locks, even during shutdown.

◆ waitUntilPreparedUnitOfWorkCommitsOrAborts()

void mongo::WiredTigerSessionCache::waitUntilPreparedUnitOfWorkCommitsOrAborts ( OperationContext * opCtx )

Waits until a prepared unit of work has ended (either been commited or aborted).

This should be used when encountering WT_PREPARE_CONFLICT errors. The caller is required to retry the conflicting WiredTiger API operation. A return from this function does not guarantee that the conflicting transaction has ended, only that one prepared unit of work in the process has signaled that it has ended. Accepts an OperationContext that will throw an AssertionException when interrupted.

This method is provided in WiredTigerSessionCache and not RecoveryUnit because all recovery units share the same session cache, and we want a recovery unit on one thread to signal all recovery units waiting for prepare conflicts across all other threads.

Member Data Documentation

◆ _cacheLock

stdx::mutex mongo::WiredTigerSessionCache::_cacheLock

private

◆ _conn

WT_CONNECTION* mongo::WiredTigerSessionCache::_conn

private

◆ _cursorEpoch

AtomicUInt64 mongo::WiredTigerSessionCache::_cursorEpoch

private

◆ _engine

WiredTigerKVEngine* mongo::WiredTigerSessionCache::_engine

private

◆ _epoch

AtomicUInt64 mongo::WiredTigerSessionCache::_epoch

private

◆ _journalListener

JournalListener* mongo::WiredTigerSessionCache::_journalListener = &NoOpJournalListener::instance

private

◆ _journalListenerMutex

stdx::mutex mongo::WiredTigerSessionCache::_journalListenerMutex

private

◆ _lastCommitOrAbortCounter

std::uint64_t mongo::WiredTigerSessionCache::_lastCommitOrAbortCounter

private

◆ _lastSyncMutex

stdx::mutex mongo::WiredTigerSessionCache::_lastSyncMutex

private

◆ _lastSyncTime

AtomicUInt32 mongo::WiredTigerSessionCache::_lastSyncTime

private

◆ _prepareCommittedOrAbortedCond

stdx::condition_variable mongo::WiredTigerSessionCache::_prepareCommittedOrAbortedCond

private

◆ _prepareCommittedOrAbortedMutex

stdx::mutex mongo::WiredTigerSessionCache::_prepareCommittedOrAbortedMutex

private

◆ _sessions

SessionCache mongo::WiredTigerSessionCache::_sessions

private

◆ _shuttingDown

AtomicUInt32 mongo::WiredTigerSessionCache::_shuttingDown

private

◆ _snapshotManager

WiredTigerSnapshotManager mongo::WiredTigerSessionCache::_snapshotManager

private

◆ _waitUntilDurableSession

WT_SESSION* mongo::WiredTigerSessionCache::_waitUntilDurableSession = nullptr

private

◆ kShuttingDownMask

const uint32_t mongo::WiredTigerSessionCache::kShuttingDownMask = 1 << 31

staticprivate

The documentation for this class was generated from the following files:

/home/louis/git/mongodbsource.github.io/src/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.h
/home/louis/git/mongodbsource.github.io/src/src/mongo/db/storage/wiredtiger/wiredtiger_session_cache.cpp

Detailed Description

Classes

Public Member Functions

Static Public Member Functions

Private Types

Private Member Functions

Private Attributes

Static Private Attributes

Member Typedef Documentation

◆ SessionCache

Constructor & Destructor Documentation

◆ WiredTigerSessionCache() [1/2]

◆ WiredTigerSessionCache() [2/2]

◆ ~WiredTigerSessionCache()

Member Function Documentation

◆ closeAll()

◆ closeAllCursors()

◆ closeCursorsForQueuedDrops()

◆ conn()

◆ getCursorEpoch()

◆ getKVEngine()

◆ getSession()

◆ isEngineCachingCursors()

◆ isEphemeral()

◆ notifyPreparedUnitOfWorkHasCommittedOrAborted()

◆ releaseSession()

◆ setJournalListener()

◆ shuttingDown()

◆ snapshotManager() [1/2]

◆ snapshotManager() [2/2]

◆ waitUntilDurable()

◆ waitUntilPreparedUnitOfWorkCommitsOrAborts()

Member Data Documentation

◆ _cacheLock

◆ _conn

◆ _cursorEpoch

◆ _engine

◆ _epoch

◆ _journalListener

◆ _journalListenerMutex

◆ _lastCommitOrAbortCounter

◆ _lastSyncMutex

◆ _lastSyncTime

◆ _prepareCommittedOrAbortedCond

◆ _prepareCommittedOrAbortedMutex

◆ _sessions

◆ _shuttingDown

◆ _snapshotManager

◆ _waitUntilDurableSession

◆ kShuttingDownMask