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Code Issues Releases Activity

migrate and split can now change sharding state (to be hooked)

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This commit is contained in:
Alberto Lerner 2010-12-03 15:40:51 -05:00
parent 4a9a5f1975
commit 433f5cb57f
2 changed files with 91 additions and 3 deletions
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51
s/d_logic.h
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@ -55,9 +55,53 @@ namespace mongo {
bool needShardChunkManager( const string& ns ) const;
ShardChunkManagerPtr getShardChunkManager( const string& ns );
bool inCriticalMigrateSection();
private:
// chunk migrate and split support
/**
* Creates and installs a new chunk manager for a given collection by "forgetting" about one of its chunks.
* The new manager uses the provided version, which has to be higher than the current manager's.
* One exception: if the forgotten chunk is the last one in this shard for the collection, version has to be 0.
*
* If it runs successfully, clients need to grab the new version to access the collection.
*
* @param ns the collection
* @param min max the chunk to eliminate from the current manager
* @param version at which the new manager should be at
*/
void donateChunk( const string& ns , const BSONObj& min , const BSONObj& max , ShardChunkVersion version );
/**
* Creates and installs a new chunk manager for a given collection by reclaiming a previously donated chunk.
* The previous manager's version has to be provided.
*
* If it runs successfully, clients that became stale by the previous donateChunk will be able to access the
* collection again.
*
* @param ns the collection
* @param min max the chunk to reclaim and add to the current manager
* @param version at which the new manager should be at
*/
void undoDonateChunk( const string& ns , const BSONObj& min , const BSONObj& max , ShardChunkVersion version );
/**
* Creates and installs a new chunk manager for a given collection by splitting one of its chunks in two or more.
* The version for the first split chunk should be provided. The subsequent chunks' version would be the latter with the
* minor portion incremented.
*
* The effect on clients will depend on the version used. If the major portion is the same as the current shards,
* clients shouldn't perceive the split.
*
* @param ns the collection
* @param min max the chunk that should be split
* @param splitKeys point in which to split
* @param version at which the new manager should be at
*/
void splitChunk( const string& ns , const BSONObj& min , const BSONObj& max , const vector<BSONObj>& splitKeys ,
ShardChunkVersion version );
bool inCriticalMigrateSection();
private:
bool _enabled;
string _configServer;
@ -72,7 +116,8 @@ namespace mongo {
NSVersionMap _versions;
// map from a namespace into the ensemble of chunk ranges that are stored in this mongod
map<string,ShardChunkManagerPtr> _chunks;
typedef map<string,ShardChunkManagerPtr> ChunkManagersMap;
ChunkManagersMap _chunks;
};
extern ShardingState shardingState;

43
s/d_state.cpp
View File

@ -127,6 +127,49 @@ namespace mongo {
}
}
void ShardingState::donateChunk( const string& ns , const BSONObj& min , const BSONObj& max , ShardChunkVersion version ) {
scoped_lock lk( _mutex );
ChunkManagersMap::const_iterator it = _chunks.find( ns );
assert( it != _chunks.end() ) ;
ShardChunkManagerPtr p = it->second;
// empty shards should have version 0
version = ( p->getNumChunks() > 1 ) ? version : ShardChunkVersion( 0 , 0 );
ShardChunkManagerPtr cloned( p->cloneMinus( min , max , version ) );
_chunks[ns] = cloned;
}
void ShardingState::undoDonateChunk( const string& ns , const BSONObj& min , const BSONObj& max , ShardChunkVersion version ) {
scoped_lock lk( _mutex );
ChunkManagersMap::const_iterator it = _chunks.find( ns );
assert( it != _chunks.end() ) ;
ShardChunkManagerPtr p( it->second->clonePlus( min , max , version ) );
_chunks[ns] = p;
}
void ShardingState::splitChunk( const string& ns , const BSONObj& min , const BSONObj& max , const vector<BSONObj>& splitKeys ,
ShardChunkVersion version ) {
scoped_lock lk( _mutex );
ChunkManagersMap::const_iterator it = _chunks.find( ns );
assert( it != _chunks.end() ) ;
ShardChunkManagerPtr p;
BSONObj startKey = min;
for ( vector<BSONObj>::const_iterator itKeys = splitKeys.begin(); itKeys != splitKeys.end(); ++itKeys ) {
BSONObj splitKey = *itKeys;
ShardChunkManagerPtr cloned( it->second->cloneSplit( startKey , max , splitKey , version ) );
version.incMinor();
startKey = splitKey;
p = cloned;
}
_chunks[ns] = p;
}
void ShardingState::setVersion( const string& ns , const ConfigVersion& version ){
scoped_lock lk(_mutex);