ShardChunkManager::ShardChunkManager( const BSONObj& collectionDoc , const BSONArray& chunksArr ) {
_fillCollectionKey( collectionDoc );
scoped_ptr<DBClientMockCursor> c ( new DBClientMockCursor( chunksArr ) );
_fillChunks( c.get() );
_fillRanges();
}
void ShardChunkManager::_init( const string& configServer , const string& ns , const string& shardName, ShardChunkManagerPtr oldManager ) {
// have to get a connection to the config db
// special case if I'm the configdb since I'm locked and if I connect to myself
// its a deadlock
scoped_ptr<ScopedDbConnection> scoped;
scoped_ptr<DBDirectClient> direct;
DBClientBase * conn;
if ( configServer.empty() ) {
direct.reset( new DBDirectClient() );
conn = direct.get();
}
else {
scoped.reset( ScopedDbConnection::getInternalScopedDbConnection( configServer, 30.0 ) );
conn = scoped->get();
}
// get this collection's sharding key
BSONObj collectionDoc = conn->findOne( "config.collections", BSON( "_id" << ns ) );
if( collectionDoc.isEmpty() ){
warning() << ns << " does not exist as a sharded collection" << endl;
return;
}
if( collectionDoc["dropped"].Bool() ){
warning() << ns << " was dropped. Re-shard collection first." << endl;
return;
}
_fillCollectionKey( collectionDoc );
map<string,ShardChunkVersion> versionMap;
versionMap[ shardName ] = _version;
_collVersion = ShardChunkVersion( 0, OID() );
// Check to see if we have an old ShardChunkManager to use
if( oldManager && oldManager->_collVersion.isSet() ){
versionMap[ shardName ] = oldManager->_version;
_collVersion = oldManager->_collVersion;
// TODO: This could be made more efficient if copying not required, but not as
// frequently reloaded as in mongos.
_chunksMap = oldManager->_chunksMap;
LOG(2) << "loading new chunks for collection " << ns << " using old chunk manager w/ version " << _collVersion
<< " and " << _chunksMap.size() << " chunks" << endl;
}
// Attach our config diff tracker to our range map and versions
SCMConfigDiffTracker differ( shardName );
differ.attach( ns, _chunksMap, _collVersion, versionMap );
// Need to do the query ourselves, since we may use direct conns to the db
Query query = differ.configDiffQuery();
auto_ptr<DBClientCursor> cursor = conn->query( "config.chunks" , query );
uassert( 16181, str::stream() << "could not initialize cursor to config server chunks collection for ns " << ns, cursor.get() );
// Diff tracker should *always* find at least one chunk if collection exists
int diffsApplied = differ.calculateConfigDiff( *cursor );
if( diffsApplied > 0 ){
LOG(2) << "loaded " << diffsApplied << " chunks into new chunk manager for " << ns
<< " with version " << _collVersion << endl;
// Save the new version of this shard
_version = versionMap[ shardName ];
_fillRanges();
}
else if( diffsApplied == 0 ){
// No chunks were found for the ns
warning() << "no chunks found when reloading " << ns << ", previous version was " << _collVersion << endl;
_version = ShardChunkVersion( 0, OID() );
_collVersion = ShardChunkVersion( 0, OID() );
_chunksMap.clear();
}
else{
// TODO: make this impossible by making sure we don't migrate / split on this shard during the
// reload
// No chunks were found for the ns
warning() << "invalid chunks found when reloading " << ns << ", previous version was " << _collVersion
<< ", this should be rare" << endl;
// Handle the same way as a connectivity error, for now
// TODO: handle inline
uassert( 16229,
str::stream() << "could not initialize cursor to config server chunks collection for ns "
<< ns, cursor.get() );
}
if ( scoped.get() )
scoped->done();
if ( _chunksMap.empty() )
log() << "no chunk for collection " << ns << " on shard " << shardName << endl;
}
