ShardChunkManagerPtr ShardingState::getShardChunkManager( const string& ns ){
scoped_lock lk( _mutex );
ChunkManagersMap::const_iterator it = _chunks.find( ns );
if ( it == _chunks.end() ) {
return ShardChunkManagerPtr();
} else {
return it->second;
}
}
ShardChunkManagerPtr ShardingState::getShardChunkManager( const string& ns ){
ConfigVersion version;
{
// check cache
scoped_lock lk( _mutex );
NSVersionMap::const_iterator it = _versions.find( ns );
if ( it == _versions.end() ) {
return ShardChunkManagerPtr();
}
version = it->second;
// TODO SERVER-1849 pending drop work
// the manager should use the cached version only if the versions match exactly
ShardChunkManagerPtr p = _chunks[ns];
if ( p && p->getVersion() >= version ){
// our cached version is good, so just return
return p;
}
}
// load the chunk information for this shard from the config database
// a reminder: ShardChunkManager may throw on construction
const string c = (_configServer == _shardHost) ? "" /* local */ : _configServer;
ShardChunkManagerPtr p( new ShardChunkManager( c , ns , _shardName ) );
// TODO SERVER-1849 verify that the manager's version is exactly the one requested
// If not, do update _chunks, but fail the request.
{
scoped_lock lk( _mutex );
_chunks[ns] = p;
}
return p;
}
DocumentSourceCursor::CursorWithContext::CursorWithContext( const string& ns )
: _readContext( ns ) // Take a read lock.
, _chunkMgr(shardingState.needShardChunkManager( ns )
? shardingState.getShardChunkManager( ns )
: ShardChunkManagerPtr())
{}
ShardChunkManagerPtr QueryResponseBuilder::newChunkManager() const {
if ( !shardingState.needShardChunkManager( _parsedQuery.ns() ) ) {
return ShardChunkManagerPtr();
}
return shardingState.getShardChunkManager( _parsedQuery.ns() );
}
