Just pass through to getDur(). More...

#include <dur_recovery_unit.h>

Inheritance diagram for mongo::DurRecoveryUnit:

Detailed Description

Just pass through to getDur().

Classes
struct	Write
	These are memory writes inside the mmapv1 mmap-ed files. More...

Public Member Functions
	DurRecoveryUnit ()

void	beginUnitOfWork (OperationContext *opCtx) final
	Marks the beginning of a unit of work. More...

void	commitUnitOfWork () final
	Marks the end of a unit of work and commits all changes registered by calls to onCommit or registerChange, in order. More...

void	abortUnitOfWork () final
	Marks the end of a unit of work and rolls back all changes registered by calls to onRollback or registerChange, in reverse order. More...

virtual bool	waitUntilDurable ()
	Waits until all commits that happened before this call are durable in the journal. More...

virtual void	abandonSnapshot ()
	If there is an open transaction, it is closed. More...

virtual void	registerChange (Change *change)
	The RecoveryUnit takes ownership of the change. More...

virtual void *	writingPtr (void *addr, size_t len)
	Declare that the data at [x, x + len) is being written. More...

virtual void	setRollbackWritesDisabled ()
	Sets a flag that declares this RecoveryUnit will skip rolling back writes, for the duration of the current outermost WriteUnitOfWork. More...

virtual SnapshotId	getSnapshotId () const
	Gets the local SnapshotId. More...

virtual void	setOrderedCommit (bool orderedCommit)

Public Member Functions inherited from mongo::RecoveryUnit
virtual	~RecoveryUnit ()

virtual void	prepareUnitOfWork ()
	Transitions the active unit of work to the "prepared" state. More...

virtual void	setIgnorePrepared (bool ignore)
	Sets whether or not to ignore prepared transactions if supported by this storage engine. More...

virtual bool	waitUntilUnjournaledWritesDurable ()
	Unlike `waitUntilDurable`, this method takes a stable checkpoint, making durable any writes on unjournaled tables that are behind the current stable timestamp. More...

virtual void	preallocateSnapshot ()
	Informs the RecoveryUnit that a snapshot will be needed soon, if one was not already established. More...

virtual Status	obtainMajorityCommittedSnapshot ()
	Obtains a majority committed snapshot. More...

virtual boost::optional< Timestamp >	getPointInTimeReadTimestamp () const
	Returns the Timestamp being used by this recovery unit or boost::none if not reading from a point in time. More...

virtual Status	setTimestamp (Timestamp timestamp)
	Sets a timestamp to assign to future writes in a transaction. More...

virtual void	setCommitTimestamp (Timestamp timestamp)
	Sets a timestamp that will be assigned to all future writes on this RecoveryUnit until clearCommitTimestamp() is called. More...

virtual void	clearCommitTimestamp ()

virtual Timestamp	getCommitTimestamp ()

virtual void	setPrepareTimestamp (Timestamp timestamp)
	Sets a prepare timestamp for the current transaction. More...

virtual void	setTimestampReadSource (ReadSource source, boost::optional< Timestamp > provided=boost::none)
	Sets which timestamp to use for read transactions. More...

virtual ReadSource	getTimestampReadSource () const

template<typename Callback >
void	onRollback (Callback callback)
	Registers a callback to be called if the current WriteUnitOfWork rolls back. More...

template<typename Callback >
void	onCommit (Callback callback)
	Registers a callback to be called if the current WriteUnitOfWork commits. More...

int &	writingInt (int &d)
	Declare write intent for an int. More...

template<typename T >
T *	writing (T *x)
	A templated helper for writingPtr. More...

Private Types
typedef OwnedPointerVector< Change >	Changes

typedef std::set< Write, Write::compareEnd >	MergedWrites
	Writes are ordered by ending address, so MergedWrites::upper_bound() can find the first overlapping write, if any. More...

typedef std::vector< Write >	InitialWrites

Private Member Functions
void	commitChanges ()
	Marks writes for journaling, if enabled, and then commits all other Changes in order. More...

void	markWritesForJournaling ()
	Creates a list of write intents to be journaled, and hands it of to the active DurabilityInterface. More...

void	rollbackChanges ()
	Restores state by rolling back all writes using the saved pre-images, and then rolling back all other Changes in LIFO order. More...

void	mergingWritingPtr (char *data, size_t len)
	Version of writingPtr that checks existing writes for overlap and only stores those changes not yet covered by an existing write intent and pre-image. More...

void	resetChanges ()
	Reset to a clean state without any uncommitted changes or write. More...

Private Attributes
Changes	_changes

size_t	_writeCount

size_t	_writeBytes

MergedWrites	_mergedWrites

InitialWrites	_initialWrites

std::string	_preimageBuffer

bool	_inUnitOfWork

bool	_rollbackWritesDisabled

Additional Inherited Members
Public Types inherited from mongo::RecoveryUnit
enum	ReadSource { kNone, kMajorityCommitted, kLastApplied, kLastAppliedSnapshot, kProvided }
	The ReadSource indicates which exteral or provided timestamp to read from for future transactions. More...

Protected Member Functions inherited from mongo::RecoveryUnit
	RecoveryUnit ()

Member Typedef Documentation

◆ Changes

typedef OwnedPointerVector<Change> mongo::DurRecoveryUnit::Changes

private

◆ InitialWrites

typedef std::vector<Write> mongo::DurRecoveryUnit::InitialWrites

private

◆ MergedWrites

typedef std::set<Write, Write::compareEnd> mongo::DurRecoveryUnit::MergedWrites

private

Writes are ordered by ending address, so MergedWrites::upper_bound() can find the first overlapping write, if any.

Overlapping and duplicate regions are forbidden, as rollback of MergedChanges undoes changes by address rather than LIFO order. In addition, empty regions are not allowed. Storing writes by age does not work well for large indexed arrays, as coalescing is needed to bound the size of the preimage buffer.

Constructor & Destructor Documentation

◆ DurRecoveryUnit()

mongo::DurRecoveryUnit::DurRecoveryUnit ( )

Member Function Documentation

◆ abandonSnapshot()

void mongo::DurRecoveryUnit::abandonSnapshot ( )

virtual

If there is an open transaction, it is closed.

On return no transaction is active. This cannot be called inside of a WriteUnitOfWork, and should fail if it is.

Implements mongo::RecoveryUnit.

◆ abortUnitOfWork()

void mongo::DurRecoveryUnit::abortUnitOfWork ( )

finalvirtual

Marks the end of a unit of work and rolls back all changes registered by calls to onRollback or registerChange, in reverse order.

Must be matched by exactly one preceding call to beginUnitOfWork.

Should be called through WriteUnitOfWork rather than directly.

Implements mongo::RecoveryUnit.

◆ beginUnitOfWork()

void mongo::DurRecoveryUnit::beginUnitOfWork ( OperationContext * opCtx )

finalvirtual

Marks the beginning of a unit of work.

Each call must be matched with exactly one call to either commitUnitOfWork or abortUnitOfWork.

Should be called through WriteUnitOfWork rather than directly.

Implements mongo::RecoveryUnit.

◆ commitChanges()

void mongo::DurRecoveryUnit::commitChanges ( )

private

Marks writes for journaling, if enabled, and then commits all other Changes in order.

Returns with empty _initialWrites, _mergedWrites, _changes and _preimageBuffer, but does not reset the _rollbackWritesDisabled or _mustRollback flags. This leaves the RecoveryUnit ready for more changes that may be committed or rolled back.

◆ commitUnitOfWork()

void mongo::DurRecoveryUnit::commitUnitOfWork ( )

finalvirtual

Marks the end of a unit of work and commits all changes registered by calls to onCommit or registerChange, in order.

Must be matched by exactly one preceding call to beginUnitOfWork.

Should be called through WriteUnitOfWork rather than directly.

Implements mongo::RecoveryUnit.

◆ getSnapshotId()

virtual SnapshotId mongo::DurRecoveryUnit::getSnapshotId ( ) const

inlinevirtual

Gets the local SnapshotId.

It is only valid to compare SnapshotIds generated by a single RecoveryUnit.

This is unrelated to Timestamp which must be globally comparable.

Implements mongo::RecoveryUnit.

◆ markWritesForJournaling()

void mongo::DurRecoveryUnit::markWritesForJournaling ( )

private

Creates a list of write intents to be journaled, and hands it of to the active DurabilityInterface.

◆ mergingWritingPtr()

void mongo::DurRecoveryUnit::mergingWritingPtr	(	char *	data,
		size_t	len
	)

private

Version of writingPtr that checks existing writes for overlap and only stores those changes not yet covered by an existing write intent and pre-image.

◆ registerChange()

void mongo::DurRecoveryUnit::registerChange ( Change * change )

virtual

The RecoveryUnit takes ownership of the change.

The commitUnitOfWork() method calls the commit() method of each registered change in order of registration. The endUnitOfWork() method calls the rollback() method of each registered Change in reverse order of registration. Either will unregister and delete the changes.

The registerChange() method may only be called when a WriteUnitOfWork is active, and may not be called during commit or rollback.

Implements mongo::RecoveryUnit.

◆ resetChanges()

void mongo::DurRecoveryUnit::resetChanges ( )

private

Reset to a clean state without any uncommitted changes or write.

◆ rollbackChanges()

void mongo::DurRecoveryUnit::rollbackChanges ( )

private

Restores state by rolling back all writes using the saved pre-images, and then rolling back all other Changes in LIFO order.

Resets internal state.

◆ setOrderedCommit()

virtual void mongo::DurRecoveryUnit::setOrderedCommit ( bool orderedCommit )

inlinevirtual

Implements mongo::RecoveryUnit.

◆ setRollbackWritesDisabled()

void mongo::DurRecoveryUnit::setRollbackWritesDisabled ( )

virtual

Sets a flag that declares this RecoveryUnit will skip rolling back writes, for the duration of the current outermost WriteUnitOfWork.

This function can only be called between a pair of unnested beginUnitOfWork() / endUnitOfWork() calls. The flag is cleared when endUnitOfWork() is called. While the flag is set, rollback will skip rolling back writes, but custom rollback change functions are still called. Clearly, this functionality should only be used when writing to temporary collections that can be cleaned up externally. For example, foreground index builds write to a temporary collection; if something goes wrong that normally requires a rollback, we can instead clean up the index by dropping the entire index. Setting the flag may permit increased performance.

Implements mongo::RecoveryUnit.

◆ waitUntilDurable()

bool mongo::DurRecoveryUnit::waitUntilDurable ( )

virtual

Waits until all commits that happened before this call are durable in the journal.

Returns true, unless the storage engine cannot guarantee durability, which should never happen when isDurable() returned true. This cannot be called from inside a unit of work, and should fail if it is.

Returns: Whether or not the storage engine can guarantee durability.

Implements mongo::RecoveryUnit.

◆ writingPtr()

void * mongo::DurRecoveryUnit::writingPtr	(	void *	data,
		size_t	len
	)

virtual

Declare that the data at [x, x + len) is being written.

Implements mongo::RecoveryUnit.

Member Data Documentation

◆ _changes

Changes mongo::DurRecoveryUnit::_changes

private

◆ _initialWrites

InitialWrites mongo::DurRecoveryUnit::_initialWrites

private

◆ _inUnitOfWork

bool mongo::DurRecoveryUnit::_inUnitOfWork

private

◆ _mergedWrites

MergedWrites mongo::DurRecoveryUnit::_mergedWrites

private

◆ _preimageBuffer

std::string mongo::DurRecoveryUnit::_preimageBuffer

private

◆ _rollbackWritesDisabled

bool mongo::DurRecoveryUnit::_rollbackWritesDisabled

private

◆ _writeBytes

size_t mongo::DurRecoveryUnit::_writeBytes

private

◆ _writeCount

size_t mongo::DurRecoveryUnit::_writeCount

private

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

/home/louis/git/mongodbsource.github.io/src/src/mongo/db/storage/mmap_v1/dur_recovery_unit.h
/home/louis/git/mongodbsource.github.io/src/src/mongo/db/storage/mmap_v1/dur_recovery_unit.cpp

Detailed Description

Classes

Public Member Functions

Private Types

Private Member Functions

Private Attributes

Additional Inherited Members

Member Typedef Documentation

◆ Changes

◆ InitialWrites

◆ MergedWrites

Constructor & Destructor Documentation

◆ DurRecoveryUnit()

Member Function Documentation

◆ abandonSnapshot()

◆ abortUnitOfWork()

◆ beginUnitOfWork()

◆ commitChanges()

◆ commitUnitOfWork()

◆ getSnapshotId()

◆ markWritesForJournaling()

◆ mergingWritingPtr()

◆ registerChange()

◆ resetChanges()

◆ rollbackChanges()

◆ setOrderedCommit()

◆ setRollbackWritesDisabled()

◆ waitUntilDurable()

◆ writingPtr()

Member Data Documentation

◆ _changes

◆ _initialWrites

◆ _inUnitOfWork

◆ _mergedWrites

◆ _preimageBuffer

◆ _rollbackWritesDisabled

◆ _writeBytes

◆ _writeCount