#include <mmap_v1_extent_manager.h>

Inheritance diagram for mongo::MmapV1ExtentManager:

Detailed Description

one per database
responsible for managing <db>.# files
NOT responsible for .ns file
gives out extents
responsible for figuring out how to get a new extent
can use any method it wants to do so
this structure is NOT stored on disk
this class is thread safe, except as indicated below

Implementation:

ExtentManager holds a preallocated list of DataFile
files will not be removed from the EM, so _files access can be lock-free
extent size and loc are immutable
Any non-const public operations on an ExtentManager will acquire an MODE_X lock on its RESOURCE_MMAPv1_EXTENT_MANAGER resource from the lock-manager, which will extend life to during WriteUnitOfWorks that might need rollback. Private methods will only be called from public ones.

Classes
class	Factory

class	FilesArray
	Simple wrapper around an array object to allow append-only modification of the array, as well as concurrent read-accesses. More...

Public Member Functions
	MmapV1ExtentManager (StringData dbname, StringData path, bool directoryPerDB)

void	close (OperationContext *opCtx)
	Must be called before destruction. More...

Status	init (OperationContext *opCtx)
	opens all current files, not thread safe More...

int	numFiles () const

long long	fileSize () const

DiskLoc	allocateExtent (OperationContext *opCtx, bool capped, int size, bool enforceQuota)

void	freeExtents (OperationContext *opCtx, DiskLoc firstExt, DiskLoc lastExt)
	firstExt has to be == lastExt or a chain More...

void	freeExtent (OperationContext *opCtx, DiskLoc extent)
	frees a single extent ignores all fields in the Extent except: magic, myLoc, length More...

void	freeListStats (OperationContext opCtx, int numExtents, int64_t *totalFreeSizeBytes) const
	Retrieve statistics on the the free list managed by this ExtentManger. More...

MmapV1RecordHeader *	recordForV1 (const DiskLoc &loc) const

std::unique_ptr< RecordFetcher >	recordNeedsFetch (const DiskLoc &loc) const
	The extent manager tracks accesses to DiskLocs. More...

Extent *	extentForV1 (const DiskLoc &loc) const

DiskLoc	extentLocForV1 (const DiskLoc &loc) const

Extent *	getExtent (const DiskLoc &loc, bool doSanityCheck=true) const

DataFileVersion	getFileFormat (OperationContext *opCtx) const final
	Not thread safe, requires a database exclusive lock. More...

void	setFileFormat (OperationContext *opCtx, DataFileVersion newVersion) final

const DataFile *	getOpenFile (int n) const final

virtual int	maxSize () const

virtual CacheHint *	cacheHint (const DiskLoc &extentLoc, const HintType &hint)
	Tell the system that for this extent, it will have this kind of disk access. More...

Public Member Functions inherited from mongo::ExtentManager
	ExtentManager ()

virtual	~ExtentManager ()

virtual int	minSize () const

virtual int	followupSize (int recordLen, int lastExtentLen) const

virtual int	initialSize (int recordLen) const
	get a suggested size for the first extent in a namespace More...

virtual int	quantizeExtentSize (int size) const
	quantizes extent size to >= min + page boundary More...

Private Member Functions
	MONGO_DISALLOW_COPYING (MmapV1ExtentManager)

DiskLoc	_allocFromFreeList (OperationContext *opCtx, int approxSize, bool capped)
	will return NULL if nothing suitable in free list More...

DiskLoc	_createExtent (OperationContext *opCtx, int approxSize, bool enforceQuota)

DataFile *	_addAFile (OperationContext *opCtx, int sizeNeeded, bool preallocateNextFile)

MmapV1RecordHeader *	_recordForV1 (const DiskLoc &loc) const
	Shared record retrieval logic used by the public recordForV1() and likelyInPhysicalMem() above. More...

DiskLoc	_getFreeListStart () const

DiskLoc	_getFreeListEnd () const

void	_setFreeListStart (OperationContext *opCtx, DiskLoc loc)

void	_setFreeListEnd (OperationContext *opCtx, DiskLoc loc)

const DataFile *	_getOpenFile (int fileId) const

DataFile *	_getOpenFile (int fileId)

DiskLoc	_createExtentInFile (OperationContext opCtx, int fileNo, DataFile f, int size, bool enforceQuota)

boost::filesystem::path	_fileName (int n) const

Private Attributes
const std::string	_dbname

const std::string	_path

const bool	_directoryPerDB

const ResourceId	_rid

RecordAccessTracker *	_recordAccessTracker

FilesArray	_files

Additional Inherited Members
Public Types inherited from mongo::ExtentManager
enum	HintType { Sequential, Random }

Constructor & Destructor Documentation

◆ MmapV1ExtentManager()

mongo::MmapV1ExtentManager::MmapV1ExtentManager	(	StringData	dbname,
		StringData	path,
		bool	directoryPerDB
	)

Parameters

freeListDetails this is a reference into the .ns file while a bit odd, this is not a layer violation as extents are a peer to the .ns file, without any layering

Member Function Documentation

◆ _addAFile()

DataFile * mongo::MmapV1ExtentManager::_addAFile	(	OperationContext *	opCtx,
		int	sizeNeeded,
		bool	preallocateNextFile
	)

private

◆ _allocFromFreeList()

DiskLoc mongo::MmapV1ExtentManager::_allocFromFreeList	(	OperationContext *	opCtx,
		int	approxSize,
		bool	capped
	)

private

will return NULL if nothing suitable in free list

◆ _createExtent()

DiskLoc mongo::MmapV1ExtentManager::_createExtent	(	OperationContext *	opCtx,
		int	approxSize,
		bool	enforceQuota
	)

private

◆ _createExtentInFile()

DiskLoc mongo::MmapV1ExtentManager::_createExtentInFile	(	OperationContext *	opCtx,
		int	fileNo,
		DataFile *	f,
		int	size,
		bool	enforceQuota
	)

private

◆ _fileName()

boost::filesystem::path mongo::MmapV1ExtentManager::_fileName ( int n ) const

private

◆ _getFreeListEnd()

DiskLoc mongo::MmapV1ExtentManager::_getFreeListEnd ( ) const

private

◆ _getFreeListStart()

DiskLoc mongo::MmapV1ExtentManager::_getFreeListStart ( ) const

private

◆ _getOpenFile() [1/2]

const DataFile * mongo::MmapV1ExtentManager::_getOpenFile ( int fileId ) const

private

◆ _getOpenFile() [2/2]

DataFile * mongo::MmapV1ExtentManager::_getOpenFile ( int fileId )

private

◆ _recordForV1()

MmapV1RecordHeader * mongo::MmapV1ExtentManager::_recordForV1 ( const DiskLoc & loc ) const

private

Shared record retrieval logic used by the public recordForV1() and likelyInPhysicalMem() above.

◆ _setFreeListEnd()

void mongo::MmapV1ExtentManager::_setFreeListEnd	(	OperationContext *	opCtx,
		DiskLoc	loc
	)

private

◆ _setFreeListStart()

void mongo::MmapV1ExtentManager::_setFreeListStart	(	OperationContext *	opCtx,
		DiskLoc	loc
	)

private

◆ allocateExtent()

DiskLoc mongo::MmapV1ExtentManager::allocateExtent	(	OperationContext *	opCtx,
		bool	capped,
		int	size,
		bool	enforceQuota
	)

virtual

Implements mongo::ExtentManager.

◆ cacheHint()

ExtentManager::CacheHint * mongo::MmapV1ExtentManager::cacheHint	(	const DiskLoc &	extentLoc,
		const HintType &	hint
	)

virtual

Tell the system that for this extent, it will have this kind of disk access.

Caller takes owernship of CacheHint

Implements mongo::ExtentManager.

◆ close()

void mongo::MmapV1ExtentManager::close ( OperationContext * opCtx )

inlinevirtual

Must be called before destruction.

Implements mongo::ExtentManager.

◆ extentForV1()

Extent * mongo::MmapV1ExtentManager::extentForV1 ( const DiskLoc & loc ) const

virtual

Parameters

loc	- has to be for a specific MmapV1RecordHeader (not an Extent) Note(erh) see comment on recordFor

Implements mongo::ExtentManager.

◆ extentLocForV1()

DiskLoc mongo::MmapV1ExtentManager::extentLocForV1 ( const DiskLoc & loc ) const

virtual

Parameters

loc	- has to be for a specific MmapV1RecordHeader (not an Extent) Note(erh) see comment on recordFor

Implements mongo::ExtentManager.

◆ fileSize()

long long mongo::MmapV1ExtentManager::fileSize ( ) const

virtual

Implements mongo::ExtentManager.

◆ freeExtent()

void mongo::MmapV1ExtentManager::freeExtent	(	OperationContext *	opCtx,
		DiskLoc	extent
	)

virtual

frees a single extent ignores all fields in the Extent except: magic, myLoc, length

Implements mongo::ExtentManager.

◆ freeExtents()

void mongo::MmapV1ExtentManager::freeExtents	(	OperationContext *	opCtx,
		DiskLoc	firstExt,
		DiskLoc	lastExt
	)

virtual

firstExt has to be == lastExt or a chain

Implements mongo::ExtentManager.

◆ freeListStats()

void mongo::MmapV1ExtentManager::freeListStats	(	OperationContext *	opCtx,
		int *	numExtents,
		int64_t *	totalFreeSizeBytes
	)		const

virtual

Retrieve statistics on the the free list managed by this ExtentManger.

Parameters

numExtents	- non-null pointer to an int that will receive the number of extents
totalFreeSizeBytes	- non-null pointer to an int64_t receiving the total free space in the free list.

Implements mongo::ExtentManager.

◆ getExtent()

Extent * mongo::MmapV1ExtentManager::getExtent	(	const DiskLoc &	loc,
		bool	doSanityCheck = `true`
	)		const

virtual

Parameters

loc	- has to be for a specific Extent

Implements mongo::ExtentManager.

◆ getFileFormat()

DataFileVersion mongo::MmapV1ExtentManager::getFileFormat ( OperationContext * opCtx ) const

finalvirtual

Not thread safe, requires a database exclusive lock.

Implements mongo::ExtentManager.

◆ getOpenFile()

const DataFile* mongo::MmapV1ExtentManager::getOpenFile ( int n ) const

inlinefinalvirtual

Implements mongo::ExtentManager.

◆ init()

Status mongo::MmapV1ExtentManager::init ( OperationContext * opCtx )

virtual

opens all current files, not thread safe

Implements mongo::ExtentManager.

◆ maxSize()

int mongo::MmapV1ExtentManager::maxSize ( ) const

virtual

Returns: maximum size of an Extent

Implements mongo::ExtentManager.

◆ MONGO_DISALLOW_COPYING()

mongo::MmapV1ExtentManager::MONGO_DISALLOW_COPYING ( MmapV1ExtentManager )

private

◆ numFiles()

int mongo::MmapV1ExtentManager::numFiles ( ) const

virtual

Implements mongo::ExtentManager.

◆ recordForV1()

MmapV1RecordHeader * mongo::MmapV1ExtentManager::recordForV1 ( const DiskLoc & loc ) const

virtual

Parameters

loc	- has to be for a specific MmapV1RecordHeader Note(erh): this sadly cannot be removed. A MmapV1RecordHeader DiskLoc has an offset from a file, while a RecordStore really wants an offset from an extent. This intrinsically links an original record store to the original extent manager.

Implements mongo::ExtentManager.

◆ recordNeedsFetch()

std::unique_ptr< RecordFetcher > mongo::MmapV1ExtentManager::recordNeedsFetch ( const DiskLoc & loc ) const

virtual

The extent manager tracks accesses to DiskLocs.

This returns non-NULL if the DiskLoc has been recently accessed, and therefore has likely been paged into physical memory. Returns nullptr if the DiskLoc is Null.

Implements mongo::ExtentManager.

◆ setFileFormat()

void mongo::MmapV1ExtentManager::setFileFormat	(	OperationContext *	opCtx,
		DataFileVersion	newVersion
	)

finalvirtual

Implements mongo::ExtentManager.

Member Data Documentation

◆ _dbname

const std::string mongo::MmapV1ExtentManager::_dbname

private

◆ _directoryPerDB

const bool mongo::MmapV1ExtentManager::_directoryPerDB

private

◆ _files

FilesArray mongo::MmapV1ExtentManager::_files

private

◆ _path

const std::string mongo::MmapV1ExtentManager::_path

private

◆ _recordAccessTracker

RecordAccessTracker* mongo::MmapV1ExtentManager::_recordAccessTracker

private

◆ _rid

const ResourceId mongo::MmapV1ExtentManager::_rid

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/mmap_v1_extent_manager.h
/home/louis/git/mongodbsource.github.io/src/src/mongo/db/storage/mmap_v1/mmap_v1_extent_manager.cpp

Detailed Description

Classes

Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Constructor & Destructor Documentation

◆ MmapV1ExtentManager()

Member Function Documentation

◆ _addAFile()

◆ _allocFromFreeList()

◆ _createExtent()

◆ _createExtentInFile()

◆ _fileName()

◆ _getFreeListEnd()

◆ _getFreeListStart()

◆ _getOpenFile() [1/2]

◆ _getOpenFile() [2/2]

◆ _recordForV1()

◆ _setFreeListEnd()

◆ _setFreeListStart()

◆ allocateExtent()

◆ cacheHint()

◆ close()

◆ extentForV1()

◆ extentLocForV1()

◆ fileSize()

◆ freeExtent()

◆ freeExtents()

◆ freeListStats()

◆ getExtent()

◆ getFileFormat()

◆ getOpenFile()

◆ init()

◆ maxSize()

◆ MONGO_DISALLOW_COPYING()

◆ numFiles()

◆ recordForV1()

◆ recordNeedsFetch()

◆ setFileFormat()

Member Data Documentation

◆ _dbname

◆ _directoryPerDB

◆ _files

◆ _path

◆ _recordAccessTracker

◆ _rid