ChunkManagerPtr DBConfig::shardCollection( const string& ns , ShardKeyPattern fieldsAndOrder , bool unique ) {
uassert( 8042 , "db doesn't have sharding enabled" , _shardingEnabled );
scoped_lock lk( _lock );
CollectionInfo& ci = _collections[ns];
uassert( 8043 , "collection already sharded" , ! ci.isSharded() );
log() << "enable sharding on: " << ns << " with shard key: " << fieldsAndOrder << endl;
// From this point on, 'ns' is going to be treated as a sharded collection. We assume this is the first
// time it is seen by the sharded system and thus create the first chunk for the collection. All the remaining
// chunks will be created as a by-product of splitting.
ci.shard( ns , fieldsAndOrder , unique );
ChunkManagerPtr cm = ci.getCM();
uassert( 13449 , "collections already sharded" , (cm->numChunks() == 0) );
cm->createFirstChunk( getPrimary() );
_save();
try {
cm->maybeChunkCollection();
}
catch ( UserException& e ) {
// failure to chunk is not critical enough to abort the command (and undo the _save()'d configDB state)
log() << "couldn't chunk recently created collection: " << ns << " " << e << endl;
}
return cm;
}
