ShardManager::ShardManager( DBConfig * config , string ns , ShardKeyPattern pattern ) : _config( config ) , _ns( ns ) , _key( pattern ){
Shard temp(0);
ScopedDbConnection conn( temp.modelServer() );
auto_ptr<DBClientCursor> cursor = conn->query( temp.getNS() , BSON( "ns" << ns ) );
while ( cursor->more() ){
Shard * s = new Shard( this );
BSONObj d = cursor->next();
s->unserialize( d );
_shards.push_back( s );
s->_id = d["_id"].wrap().getOwned();
}
conn.done();
if ( _shards.size() == 0 ){
Shard * s = new Shard( this );
s->_ns = ns;
s->_min = _key.globalMin();
s->_max = _key.globalMax();
s->_server = config->getPrimary();
s->_markModified();
_shards.push_back( s );
log() << "no shards for:" << ns << " so creating first: " << s->toString() << endl;
}
_sequenceNumber = ++NextSequenceNumber;
}
Shard * Shard::split( const BSONObj& m ){
uassert( "can't split as shard that doesn't have a manager" , _manager );
log(1) << " before split on: " << m << "\n"
<< "\t self : " << toString() << endl;
uassert( "locking namespace on server failed" , lockNamespaceOnServer( getServer() , _ns ) );
Shard * s = new Shard( _manager );
s->_ns = _ns;
s->_server = _server;
s->_min = m.getOwned();
s->_max = _max;
s->_markModified();
_markModified();
_manager->_shards.push_back( s );
_max = m.getOwned();
log(1) << " after split:\n"
<< "\t left : " << toString() << "\n"
<< "\t right: "<< s->toString() << endl;
_manager->save();
return s;
}
bool Shard::moveAndCommit( const string& to , string& errmsg ){
uassert( "can't move shard to its current location!" , to != getServer() );
log() << "moving shard ns: " << _ns << " moving shard: " << toString() << " " << _server << " -> " << to << endl;
string from = _server;
ServerShardVersion oldVersion = _manager->getVersion( from );
BSONObj filter;
{
BSONObjBuilder b;
getFilter( b );
filter = b.obj();
}
ScopedDbConnection fromconn( from );
BSONObj startRes;
bool worked = fromconn->runCommand( "admin" ,
BSON( "moveshard.start" << _ns <<
"from" << from <<
"to" << to <<
"filter" << filter
) ,
startRes
);
if ( ! worked ){
errmsg = (string)"moveshard.start failed: " + startRes.toString();
return false;
}
// update config db
setServer( to );
// need to increment version # for old server
Shard * randomShardOnOldServer = _manager->findShardOnServer( from );
if ( randomShardOnOldServer )
randomShardOnOldServer->_markModified();
_manager->save();
BSONObj finishRes;
{
ServerShardVersion newVersion = _manager->getVersion( from );
uassert( "version has to be higher" , newVersion > oldVersion );
BSONObjBuilder b;
b << "moveshard.finish" << _ns;
b << "to" << to;
b.appendTimestamp( "newVersion" , newVersion );
b.append( startRes["finishToken"] );
worked = fromconn->runCommand( "admin" ,
b.done() ,
finishRes );
}
if ( ! worked ){
errmsg = (string)"moveshard.finish failed: " + finishRes.toString();
return false;
}
fromconn.done();
return true;
}
