Classes
class	Already
	Bitmap to remember things we have already marked for journaling. More...

class	BufferGuard
	Used inside the journal writer thread to ensure that used buffers are cleaned up properly. More...

class	BufReaderUnitTest

struct	BufReaderY

class	CommitJob
	Tracks all write operations on the private view so they can be journaled. More...

class	DropDbOp
	record drop of a database More...

class	DurableInterface

class	DurOp
	DurOp - Operations we journal that aren't just basic writes. More...

class	FileCreatedOp
	indicates creation of a new file More...

struct	JDbContext
	declares "the next entry(s) are for this database / file path prefix" More...

struct	JEntry
	an individual write operation within a group commit section. More...

struct	JHeader
	beginning header for a journal/j._<n> file there is nothing important int this header at this time. More...

class	Journal
	the writeahead journal for durability More...

class	JournalSectionIterator
	read through the memory mapped data of a journal file (journal/j._<n> file) throws More...

class	JournalWriter
	Manages the thread and queues used for writing the journal to disk and notify parties with are waiting on the write concern. More...

struct	JSectFooter
	group commit section footer. More...

struct	JSectHeader
	"Section" header. More...

struct	LSNFile
	"last sequence number" More...

struct	ParsedJournalEntry

class	RecoveryJob
	call go() to execute a recovery from existing journal files. More...

struct	Stats
	journaling stats. More...

struct	WriteIntent
	Declaration of an intent to write to a region of a memory mapped view. More...

Typedefs
typedef std::vector< std::shared_ptr< DurOp > >	DurOpsVector

typedef std::vector< WriteIntent >	WriteIntentsVector

Functions
void	PREPLOGBUFFER (JSectHeader &outHeader, AlignedBuilder &outBuffer, ClockSource *cs, int64_t serverStartMs)

boost::filesystem::path	getJournalDir ()

void	preallocateFiles ()

static void	durThread (ClockSource *cs, int64_t serverStartMs)
	The main durability thread loop. More...

static void	remapPrivateView (OperationContext *opCtx, double fraction)
	Remaps the private view from the shared view so that it does not consume too much copy-on-write/swap space. More...

void	startup (ClockSource *cs, int64_t serverStartMs)
	Invoked at server startup. More...

void	setJournalListener (JournalListener *jl)

JournalListener *	getJournalListener ()

MONGO_INITIALIZER()	InitializeJournalingParams (InitializerContext *context)

	MONGO_STATIC_ASSERT (sizeof(Checksum)==16)

	MONGO_STATIC_ASSERT (sizeof(JHeader)==8192)

	MONGO_STATIC_ASSERT (sizeof(JSectHeader)==20)

	MONGO_STATIC_ASSERT (sizeof(JSectFooter)==32)

	MONGO_STATIC_ASSERT (sizeof(JEntry)==12)

	MONGO_STATIC_ASSERT (sizeof(LSNFile)==88)

void	removeOldJournalFile (boost::filesystem::path p)

boost::filesystem::path	lsnPath ()

void	journalingFailure (const char *msg)
	this should be called when something really bad happens so that we can flag appropriately More...

bool	haveJournalFiles (bool anyFiles)
	never throws More...

void	removeJournalFiles ()
	throws More...

void	journalCleanup (bool log=false)
	at termination after db files closed & fsynced also after recovery closes and removes journal files More...

bool	_preallocateIsFaster ()

bool	preallocateIsFaster ()

void	preallocateFile (boost::filesystem::path p, unsigned long long len)

boost::filesystem::path	preallocPath (int n)

void	_preallocateFiles ()

void	checkFreeSpace ()

boost::filesystem::path	findPrealloced ()

void	journalMakeDir (ClockSource *cs, int64_t serverStartMs)
	assure journal/ dir exists. More...

unsigned long long	journalReadLSN ()
	called during recovery (the error message text below assumes that) More...

uint64_t	generateNextSeqNumber (ClockSource *cs, int64_t serverStartMs)
	Generates the next sequence number for use in the journal, guaranteed to be greater than all prior sequence numbers. More...

void	setLastSeqNumberWrittenToSharedView (uint64_t seqNumber)
	Informs the journaling system that all writes on or before the passed in sequence number have been written to the data files' shared mmap view. More...

void	notifyPreDataFileFlush ()
	Call these before (pre) and after (post) the datafiles are flushed to disk by the DataFileSync thread. More...

void	notifyPostDataFileFlush ()

void	WRITETOJOURNAL (const JSectHeader &h, const AlignedBuilder &uncompressed)
	write (append) the buffer we have built to the journal and fsync it. More...

static DurableMappedFile *	findMMF_inlock (void *ptr, size_t &ofs)

static void	prepBasicWrite_inlock (AlignedBuilder &bb, const WriteIntent *i, RelativePath &lastDbPath)
	put the basic write operation into the buffer (bb) to be journaled More...

static void	prepBasicWrites (AlignedBuilder &bb, const std::vector< WriteIntent > &intents)
	basic write ops / write intents. More...

static void	_PREPLOGBUFFER (JSectHeader &h, AlignedBuilder &bb, ClockSource *cs, int64_t serverStartMs)
	we will build an output buffer ourself and then use O_DIRECT we could be in read lock for this caller handles locking More...

static void	getFiles (boost::filesystem::path dir, vector< boost::filesystem::path > &files)
	Get journal filenames, in order. More...

static string	fileName (const char *dbName, int fileNo)

void	_recover (OperationContext *opCtx)

void	replayJournalFilesAtStartup ()
	recover from a crash called during startup throws on error More...

Variables
Stats	stats

CommitJob	commitJob

DurableInterface *DurableInterface::_impl &	nonDurableImpl

const unsigned	UncommittedBytesLimit = (sizeof(void) == 4) ? 50 1024 * 1024 : 512 * 1024 * 1024

unsigned long long	DataLimitPerJournalFile

bool	usingPreallocate = false

Journal	j

const unsigned long long	LsnShutdownSentinel = ~((unsigned long long)0)

bool	okToCleanUp = false
	at clean shutdown More...

const int	NUM_PREALLOC_FILES = 3

const long long	ExtraKeepTimeMs = 10000

const unsigned	Alignment = 8192

const RelativePath	local = RelativePath::fromRelativePath("local")

mongo::dur::BufReaderUnitTest	brunittest

Typedef Documentation

◆ DurOpsVector

typedef std::vector<std::shared_ptr<DurOp> > mongo::dur::DurOpsVector

◆ WriteIntentsVector

typedef std::vector<WriteIntent> mongo::dur::WriteIntentsVector

Function Documentation

◆ _preallocateFiles()

void mongo::dur::_preallocateFiles ( )

◆ _preallocateIsFaster()

bool mongo::dur::_preallocateIsFaster ( )

◆ _PREPLOGBUFFER()

static void mongo::dur::_PREPLOGBUFFER	(	JSectHeader &	h,
		AlignedBuilder &	bb,
		ClockSource *	cs,
		int64_t	serverStartMs
	)

static

we will build an output buffer ourself and then use O_DIRECT we could be in read lock for this caller handles locking

Returns: partially populated sectheader and _ab set

◆ _recover()

void mongo::dur::_recover ( OperationContext * opCtx )

◆ checkFreeSpace()

void mongo::dur::checkFreeSpace ( )

◆ durThread()

static void mongo::dur::durThread	(	ClockSource *	cs,
		int64_t	serverStartMs
	)

static

The main durability thread loop.

There is a single instance of this function running.

◆ fileName()

static string mongo::dur::fileName	(	const char *	dbName,
		int	fileNo
	)

static

◆ findMMF_inlock()

static DurableMappedFile* mongo::dur::findMMF_inlock	(	void *	ptr,
		size_t &	ofs
	)

static

◆ findPrealloced()

boost::filesystem::path mongo::dur::findPrealloced ( )

◆ generateNextSeqNumber()

uint64_t mongo::dur::generateNextSeqNumber	(	ClockSource *	cs,
		int64_t	serverStartMs
	)

Generates the next sequence number for use in the journal, guaranteed to be greater than all prior sequence numbers.

◆ getFiles()

static void mongo::dur::getFiles	(	boost::filesystem::path	dir,
		vector< boost::filesystem::path > &	files
	)

static

Get journal filenames, in order.

Throws if unexpected content found.

◆ getJournalDir()

boost::filesystem::path mongo::dur::getJournalDir ( )

◆ getJournalListener()

JournalListener * mongo::dur::getJournalListener ( )

◆ haveJournalFiles()

bool mongo::dur::haveJournalFiles ( bool anyFiles )

never throws

never throws.

Parameters

anyFiles by default we only look at j._* files. If anyFiles is true, return true if there are any files in the journal directory. checkForUncleanShutdown() uses this to make sure that the journal directory is mounted.

Returns: true if journal dir is not empty

Parameters

anyFiles by default we only look at j._* files. If anyFiles is true, return true if there are any files in the journal directory. checkForUncleanShutdown() uses this to make sure that the journal directory is mounted.

Returns: true if there are any journal files in the journal dir.

◆ InitializeJournalingParams()

MONGO_INITIALIZER() mongo::dur::InitializeJournalingParams ( InitializerContext * context )

◆ journalCleanup()

void mongo::dur::journalCleanup ( bool log = false )

at termination after db files closed & fsynced also after recovery closes and removes journal files

Parameters

log	report in log that we are cleaning up if we actually do any work

◆ journalingFailure()

void mongo::dur::journalingFailure ( const char * msg )

this should be called when something really bad happens so that we can flag appropriately

flag that something has gone wrong during writing to the journal (not for recovery mode)

todo: (1) don't log too much (2) make an indicator in the journal dir that something bad happened. (2b) refuse to do a recovery startup if that is there without manual override.

◆ journalMakeDir()

void mongo::dur::journalMakeDir	(	ClockSource *	cs,
		int64_t	serverStartMs
	)

assure journal/ dir exists.

throws. call during startup.

throws

◆ journalReadLSN()

unsigned long long mongo::dur::journalReadLSN ( )

called during recovery (the error message text below assumes that)

read lsn from disk from the last run before doing recovery

◆ lsnPath()

boost::filesystem::path mongo::dur::lsnPath ( )

◆ MONGO_STATIC_ASSERT() [1/6]

mongo::dur::MONGO_STATIC_ASSERT ( sizeof(Checksum) = =16 )

◆ MONGO_STATIC_ASSERT() [2/6]

mongo::dur::MONGO_STATIC_ASSERT ( sizeof(JHeader) = =8192 )

◆ MONGO_STATIC_ASSERT() [3/6]

mongo::dur::MONGO_STATIC_ASSERT ( sizeof(JSectHeader) = =20 )

◆ MONGO_STATIC_ASSERT() [4/6]

mongo::dur::MONGO_STATIC_ASSERT ( sizeof(JSectFooter) = =32 )

◆ MONGO_STATIC_ASSERT() [5/6]

mongo::dur::MONGO_STATIC_ASSERT ( sizeof(JEntry) = =12 )

◆ MONGO_STATIC_ASSERT() [6/6]

mongo::dur::MONGO_STATIC_ASSERT ( sizeof(LSNFile) = =88 )

◆ notifyPostDataFileFlush()

void mongo::dur::notifyPostDataFileFlush ( )

◆ notifyPreDataFileFlush()

void mongo::dur::notifyPreDataFileFlush ( )

Call these before (pre) and after (post) the datafiles are flushed to disk by the DataFileSync thread.

These should not be called for any other flushes.

◆ preallocateFile()

void mongo::dur::preallocateFile	(	boost::filesystem::path	p,
		unsigned long long	len
	)

◆ preallocateFiles()

void mongo::dur::preallocateFiles ( )

◆ preallocateIsFaster()

bool mongo::dur::preallocateIsFaster ( )

◆ preallocPath()

boost::filesystem::path mongo::dur::preallocPath ( int n )

inline

◆ prepBasicWrite_inlock()

static void mongo::dur::prepBasicWrite_inlock	(	AlignedBuilder &	bb,
		const WriteIntent *	i,
		RelativePath &	lastDbPath
	)

static

put the basic write operation into the buffer (bb) to be journaled

◆ prepBasicWrites()

static void mongo::dur::prepBasicWrites	(	AlignedBuilder &	bb,
		const std::vector< WriteIntent > &	intents
	)

static

basic write ops / write intents.

note there is no particular order to these : if we have two writes to the same location during the group commit interval, it is likely (although not assured) that it is journaled here once.

◆ PREPLOGBUFFER()

void mongo::dur::PREPLOGBUFFER	(	JSectHeader &	outHeader,
		AlignedBuilder &	outBuffer,
		ClockSource *	cs,
		int64_t	serverStartMs
	)

◆ remapPrivateView()

static void mongo::dur::remapPrivateView	(	OperationContext *	opCtx,
		double	fraction
	)

static

Remaps the private view from the shared view so that it does not consume too much copy-on-write/swap space.

Must only be called after the in-memory journal has been flushed to disk and applied on top of the shared view.

Parameters

fraction Value between (0, 1] indicating what fraction of the memory to remap. Remapping too much or too frequently incurs copy-on-write page fault cost.

◆ removeJournalFiles()

void mongo::dur::removeJournalFiles ( )

throws

◆ removeOldJournalFile()

void mongo::dur::removeOldJournalFile ( boost::filesystem::path p )

◆ replayJournalFilesAtStartup()

void mongo::dur::replayJournalFilesAtStartup ( )

recover from a crash called during startup throws on error

◆ setJournalListener()

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

◆ setLastSeqNumberWrittenToSharedView()

void mongo::dur::setLastSeqNumberWrittenToSharedView ( uint64_t seqNumber )

Informs the journaling system that all writes on or before the passed in sequence number have been written to the data files' shared mmap view.

◆ startup()

void mongo::dur::startup	(	ClockSource *	cs,
		int64_t	serverStartMs
	)

Invoked at server startup.

Called during startup to startup the durability module.

Recovers the database by replaying journal files and then starts the durability thread.

Does nothing if storageGlobalParams.dur is false

◆ WRITETOJOURNAL()

void mongo::dur::WRITETOJOURNAL	(	const JSectHeader &	h,
		const AlignedBuilder &	uncompressed
	)

write (append) the buffer we have built to the journal and fsync it.

Writes the specified uncompressed buffer to the journal.

outside of dbMutex lock as this could be slow.

Parameters

uncompressed - a buffer that will be written to the journal after compression will not return until on disk

Variable Documentation

◆ Alignment

const unsigned mongo::dur::Alignment = 8192

◆ brunittest

mongo::dur::BufReaderUnitTest mongo::dur::brunittest

◆ commitJob

CommitJob mongo::dur::commitJob

◆ DataLimitPerJournalFile

unsigned long long mongo::dur::DataLimitPerJournalFile

Initial value:

=

(sizeof(void*) == 4) ? 256 * 1024 * 1024 : 1 * 1024 * 1024 * 1024

◆ ExtraKeepTimeMs

const long long mongo::dur::ExtraKeepTimeMs = 10000

◆ j

Journal mongo::dur::j

◆ local

const RelativePath mongo::dur::local = RelativePath::fromRelativePath("local")

◆ LsnShutdownSentinel

const unsigned long long mongo::dur::LsnShutdownSentinel = ~((unsigned long long)0)

◆ nonDurableImpl

DurableInterface* DurableInterface::_impl& mongo::dur::nonDurableImpl

◆ NUM_PREALLOC_FILES

const int mongo::dur::NUM_PREALLOC_FILES = 3

◆ okToCleanUp

bool mongo::dur::okToCleanUp = false

at clean shutdown

true if ok to cleanup journal files at termination.

otherwise, files journal will be retained.

◆ stats

Stats mongo::dur::stats

◆ UncommittedBytesLimit

const unsigned mongo::dur::UncommittedBytesLimit = (sizeof(void*) == 4) ? 50 * 1024 * 1024 : 512 * 1024 * 1024

◆ usingPreallocate

bool mongo::dur::usingPreallocate = false

Classes

Typedefs

Functions

Variables

Typedef Documentation

◆ DurOpsVector

◆ WriteIntentsVector

Function Documentation

◆ _preallocateFiles()

◆ _preallocateIsFaster()

◆ _PREPLOGBUFFER()

◆ _recover()

◆ checkFreeSpace()

◆ durThread()

◆ fileName()

◆ findMMF_inlock()

◆ findPrealloced()

◆ generateNextSeqNumber()

◆ getFiles()

◆ getJournalDir()

◆ getJournalListener()

◆ haveJournalFiles()

◆ InitializeJournalingParams()

◆ journalCleanup()

◆ journalingFailure()

◆ journalMakeDir()

◆ journalReadLSN()

◆ lsnPath()

◆ MONGO_STATIC_ASSERT() [1/6]

◆ MONGO_STATIC_ASSERT() [2/6]

◆ MONGO_STATIC_ASSERT() [3/6]

◆ MONGO_STATIC_ASSERT() [4/6]

◆ MONGO_STATIC_ASSERT() [5/6]

◆ MONGO_STATIC_ASSERT() [6/6]

◆ notifyPostDataFileFlush()

◆ notifyPreDataFileFlush()

◆ preallocateFile()

◆ preallocateFiles()

◆ preallocateIsFaster()

◆ preallocPath()

◆ prepBasicWrite_inlock()

◆ prepBasicWrites()

◆ PREPLOGBUFFER()

◆ remapPrivateView()

◆ removeJournalFiles()

◆ removeOldJournalFile()

◆ replayJournalFilesAtStartup()

◆ setJournalListener()

◆ setLastSeqNumberWrittenToSharedView()

◆ startup()

◆ WRITETOJOURNAL()

Variable Documentation

◆ Alignment

◆ brunittest

◆ commitJob

◆ DataLimitPerJournalFile

◆ ExtraKeepTimeMs

◆ j

◆ local

◆ LsnShutdownSentinel

◆ nonDurableImpl

◆ NUM_PREALLOC_FILES

◆ okToCleanUp

◆ stats

◆ UncommittedBytesLimit

◆ usingPreallocate