mongo::ShardChunkManager Class Reference

#include <d_chunk_manager.h>

Public Member Functions
bool	belongsToMe (const BSONObj &obj) const
ShardChunkManager *	cloneMinus (const BSONObj &min, const BSONObj &max, const ShardChunkVersion &version)
ShardChunkManager *	clonePlus (const BSONObj &min, const BSONObj &max, const ShardChunkVersion &version)
ShardChunkManager *	cloneSplit (const BSONObj &min, const BSONObj &max, const vector< BSONObj > &splitKeys, const ShardChunkVersion &version)
BSONObj	getKey () const
bool	getNextChunk (const BSONObj &lookupKey, BSONObj foundMin, BSONObj foundMax) const
unsigned	getNumChunks () const
ShardChunkVersion	getVersion () const
	ShardChunkManager (const BSONObj &collectionDoc, const BSONArray &chunksDoc)
	ShardChunkManager (const string &configServer, const string &ns, const string &shardName)
string	toString () const
	~ShardChunkManager ()
Private Types
typedef map< BSONObj, BSONObj, BSONObjCmp >	RangeMap
Private Member Functions
void	_assertChunkExists (const BSONObj &min, const BSONObj &max) const
void	_fillChunks (DBClientCursorInterface *cursor)
void	_fillCollectionKey (const BSONObj &collectionDoc)
void	_fillRanges ()
	ShardChunkManager ()
Private Attributes
RangeMap	_chunksMap
BSONObj	_key
RangeMap	_rangesMap
ShardChunkVersion	_version

Detailed Description

Controls the boundaries of all the chunks for a given collection that live in this shard.

ShardChunkManager instances never change after construction. There are methods provided that would generate a new manager if new chunks are added, subtracted, or split.

TODO The responsibility of maintaining the version for a shard is still shared between this class and its caller. The manager does check corner cases (e.g. cloning out the last chunk generates a manager with version 0) but ultimately still cannot be responsible to set all versions. Currently, they are a function of the global state as opposed to the per-shard one.

Definition at line 40 of file d_chunk_manager.h.

Member Typedef Documentation

typedef map< BSONObj, BSONObj , BSONObjCmp > mongo::ShardChunkManager::RangeMap [private]

Definition at line 129 of file d_chunk_manager.h.

Constructor & Destructor Documentation

mongo::ShardChunkManager::ShardChunkManager	(	const string &	configServer,
		const string &	ns,
		const string &	shardName
	)

Loads the ShardChunkManager with all boundaries for chunks of a given collection that live in an given shard.

Parameters:

	configServer	name of the server where the configDB currently is. Can be empty to indicate that the configDB is running locally
	ns	namespace for the collections whose chunks we're interested
	shardName	name of the shard that this chunk matcher should track

This constructor throws if collection is dropped/malformed and on connectivity errors

mongo::ShardChunkManager::ShardChunkManager	(	const BSONObj &	collectionDoc,
		const BSONArray &	chunksDoc
	)

Same as the regular constructor but used in unittest (no access to configDB required).

Parameters:

	collectionDoc	simulates config.collection's entry for one colleciton
	chunksDocs	simulates config.chunks' entries for one collection's shard

mongo::ShardChunkManager::~ShardChunkManager ( ) [inline]

Definition at line 64 of file d_chunk_manager.h.

mongo::ShardChunkManager::ShardChunkManager ( ) [inline, private]

can only be used in the cloning calls

Definition at line 145 of file d_chunk_manager.h.

Member Function Documentation

void mongo::ShardChunkManager::_assertChunkExists	(	const BSONObj &	min,
		const BSONObj &	max
	)			const `[private]`

throws if the exact chunk is not in the chunks' map

void mongo::ShardChunkManager::_fillChunks ( DBClientCursorInterface * cursor ) [private]

void mongo::ShardChunkManager::_fillCollectionKey ( const BSONObj & collectionDoc ) [private]

constructors helpers

void mongo::ShardChunkManager::_fillRanges ( ) [private]

bool mongo::ShardChunkManager::belongsToMe ( const BSONObj & obj ) const

Checks whether a document belongs to this shard.

Parameters:

obj

document containing sharding keys (and, optionally, other attributes)

Returns:: true if shards hold the object

ShardChunkManager* mongo::ShardChunkManager::cloneMinus	(	const BSONObj &	min,
		const BSONObj &	max,
		const ShardChunkVersion &	version
	)

Generates a new manager based on 'this's state minus a given chunk.

Parameters:

	min	max chunk boundaries for the chunk to subtract
	version	that the resulting manager should be at. The version has to be higher than the current one. When cloning away the last chunk, verstion must be 0.

Returns:: a new ShardChunkManager, to be owned by the caller

ShardChunkManager* mongo::ShardChunkManager::clonePlus	(	const BSONObj &	min,
		const BSONObj &	max,
		const ShardChunkVersion &	version
	)

Generates a new manager based on 'this's state plus a given chunk.

Parameters:

	min	max chunk boundaries for the chunk to add
	version	that the resulting manager should be at. It can never be 0, though (see CloneMinus).

Returns:: a new ShardChunkManager, to be owned by the caller

ShardChunkManager* mongo::ShardChunkManager::cloneSplit	(	const BSONObj &	min,
		const BSONObj &	max,
		const vector< BSONObj > &	splitKeys,
		const ShardChunkVersion &	version
	)

Generates a new manager by splitting an existing chunk at one or more points.

Parameters:

	min	max boundaries of chunk to be split
	splitKeys	points to split original chunk at
	version	to be used in first chunk. The subsequent chunks would increment the minor version.

Returns:: a new ShardChunkManager with the chunk split, to be owned by the caller

BSONObj mongo::ShardChunkManager::getKey ( ) const [inline]

Definition at line 117 of file d_chunk_manager.h.

bool mongo::ShardChunkManager::getNextChunk	(	const BSONObj &	lookupKey,
		BSONObj *	foundMin,
		BSONObj *	foundMax
	)			const

Given a chunk's min key (or empty doc), gets the boundary of the chunk following that one (the first).

Parameters:

	lookupKey	is the min key for a previously obtained chunk or the empty document
	foundMin	IN/OUT min for chunk following the one starting at lookupKey
	foundMax	IN/OUT max for the above chunk