BSONObj ClusteredCursor::explain( const string& server , BSONObj extra ){
BSONObj q = _query;
if ( ! extra.isEmpty() ){
q = concatQuery( q , extra );
}
ShardConnection conn( server , _ns );
BSONObj o = conn->findOne( _ns , Query( q ).explain() );
conn.done();
return o;
}
BSONObj ClusteredCursor::explain( const string& server , BSONObj extra ){
BSONObj q = _query;
if ( ! extra.isEmpty() ){
q = concatQuery( q , extra );
}
BSONObj o;
ShardConnection conn( server , _ns );
auto_ptr<DBClientCursor> cursor = conn->query( _ns , Query( q ).explain() , abs( _batchSize ) * -1 , 0 , _fields.isEmpty() ? 0 : &_fields );
if ( cursor.get() && cursor->more() )
o = cursor->next().getOwned();
conn.done();
return o;
}
auto_ptr<DBClientCursor> ClusteredCursor::query( const string& server , int num , BSONObj extra , int skipLeft ){
uassert( 10017 , "cursor already done" , ! _done );
assert( _didInit );
BSONObj q = _query;
if ( ! extra.isEmpty() ){
q = concatQuery( q , extra );
}
ShardConnection conn( server , _ns );
if ( conn.setVersion() ){
conn.done();
throw StaleConfigException( _ns , "ClusteredCursor::query ShardConnection had to change" , true );
}
if ( logLevel >= 5 ){
log(5) << "ClusteredCursor::query (" << type() << ") server:" << server
<< " ns:" << _ns << " query:" << q << " num:" << num
<< " _fields:" << _fields << " options: " << _options << endl;
}
auto_ptr<DBClientCursor> cursor =
conn->query( _ns , q , num , 0 , ( _fields.isEmpty() ? 0 : &_fields ) , _options , _batchSize == 0 ? 0 : _batchSize + skipLeft );
assert( cursor.get() );
if ( cursor->hasResultFlag( ResultFlag_ShardConfigStale ) ){
conn.done();
throw StaleConfigException( _ns , "ClusteredCursor::query" );
}
if ( cursor->hasResultFlag( ResultFlag_ErrSet ) ){
conn.done();
BSONObj o = cursor->next();
throw UserException( o["code"].numberInt() , o["$err"].String() );
}
cursor->attach( &conn );
conn.done();
return cursor;
}
auto_ptr<DBClientCursor> ClusteredCursor::query( const string& server , int num , BSONObj extra , int skipLeft , bool lazy ) {
uassert( 10017 , "cursor already done" , ! _done );
assert( _didInit );
BSONObj q = _query;
if ( ! extra.isEmpty() ) {
q = concatQuery( q , extra );
}
try {
ShardConnection conn( server , _ns );
if ( conn.setVersion() ) {
conn.done();
throw StaleConfigException( _ns , "ClusteredCursor::query ShardConnection had to change" , true );
}
LOG(5) << "ClusteredCursor::query (" << type() << ") server:" << server
<< " ns:" << _ns << " query:" << q << " num:" << num
<< " _fields:" << _fields << " options: " << _options << endl;
auto_ptr<DBClientCursor> cursor =
conn->query( _ns , q , num , 0 , ( _fields.isEmpty() ? 0 : &_fields ) , _options , _batchSize == 0 ? 0 : _batchSize + skipLeft );
if ( ! cursor.get() && _options & QueryOption_PartialResults ) {
_done = true;
conn.done();
return cursor;
}
massert( 13633 , str::stream() << "error querying server: " << server , cursor.get() );
cursor->attach( &conn ); // this calls done on conn
assert( ! conn.ok() );
_checkCursor( cursor.get() );
return cursor;
}
catch ( SocketException& e ) {
if ( ! ( _options & QueryOption_PartialResults ) )
throw e;
_done = true;
return auto_ptr<DBClientCursor>();
}
}
auto_ptr<DBClientCursor> ShardedCursor::query( const string& server , int num , BSONObj extra ){
uassert( "cursor already done" , ! _done );
BSONObj q = _query;
if ( ! extra.isEmpty() ){
q = concatQuery( q , extra );
}
ScopedDbConnection conn( server );
checkShardVersion( conn.conn() , _ns );
log(5) << "ShardedCursor::query server:" << server << " ns:" << _ns << " query:" << q << " num:" << num << " _fields:" << _fields << " options: " << _options << endl;
auto_ptr<DBClientCursor> cursor = conn->query( _ns.c_str() , q , num , 0 , ( _fields.isEmpty() ? 0 : &_fields ) , _options );
if ( cursor->hasResultFlag( QueryResult::ResultFlag_ShardConfigStale ) )
throw StaleConfigException( _ns , "ShardedCursor::query" );
conn.done();
return cursor;
}
void ParallelSortClusteredCursor::_init() {
// log() << "Starting parallel search..." << endl;
// make sure we're not already initialized
assert( ! _cursors );
_cursors = new FilteringClientCursor[_numServers];
bool returnPartial = ( _options & QueryOption_PartialResults );
vector<ServerAndQuery> queries( _servers.begin(), _servers.end() );
set<int> retryQueries;
int finishedQueries = 0;
vector< shared_ptr<ShardConnection> > conns;
vector<string> servers;
// Since we may get all sorts of errors, record them all as they come and throw them later if necessary
vector<string> staleConfigExs;
vector<string> socketExs;
vector<string> otherExs;
bool allConfigStale = false;
int retries = -1;
// Loop through all the queries until we've finished or gotten a socket exception on all of them
// We break early for non-socket exceptions, and socket exceptions if we aren't returning partial results
do {
retries++;
bool firstPass = retryQueries.size() == 0;
if( ! firstPass ){
log() << "retrying " << ( returnPartial ? "(partial) " : "" ) << "parallel connection to ";
for( set<int>::iterator it = retryQueries.begin(); it != retryQueries.end(); ++it ){
log() << queries[*it]._server << ", ";
}
log() << finishedQueries << " finished queries." << endl;
}
size_t num = 0;
for ( vector<ServerAndQuery>::iterator it = queries.begin(); it != queries.end(); ++it ) {
size_t i = num++;
const ServerAndQuery& sq = *it;
// If we're not retrying this cursor on later passes, continue
if( ! firstPass && retryQueries.find( i ) == retryQueries.end() ) continue;
// log() << "Querying " << _query << " from " << _ns << " for " << sq._server << endl;
BSONObj q = _query;
if ( ! sq._extra.isEmpty() ) {
q = concatQuery( q , sq._extra );
}
string errLoc = " @ " + sq._server;
if( firstPass ){
// This may be the first time connecting to this shard, if so we can get an error here
try {
conns.push_back( shared_ptr<ShardConnection>( new ShardConnection( sq._server , _ns ) ) );
}
catch( std::exception& e ){
socketExs.push_back( e.what() + errLoc );
if( ! returnPartial ){
num--;
break;
}
conns.push_back( shared_ptr<ShardConnection>() );
continue;
}
servers.push_back( sq._server );
}
if ( conns[i]->setVersion() ) {
conns[i]->done();
staleConfigExs.push_back( StaleConfigException( _ns , "ClusteredCursor::query ShardConnection had to change" , true ).what() + errLoc );
break;
}
LOG(5) << "ParallelSortClusteredCursor::init server:" << sq._server << " ns:" << _ns
<< " query:" << q << " _fields:" << _fields << " options: " << _options << endl;
if( ! _cursors[i].raw() )
_cursors[i].reset( new DBClientCursor( conns[i]->get() , _ns , q ,
0 , // nToReturn
0 , // nToSkip
_fields.isEmpty() ? 0 : &_fields , // fieldsToReturn
_options ,
_batchSize == 0 ? 0 : _batchSize + _needToSkip // batchSize
) );
try{
_cursors[i].raw()->initLazy( ! firstPass );
}
catch( SocketException& e ){
socketExs.push_back( e.what() + errLoc );
_cursors[i].reset( NULL );
conns[i]->done();
if( ! returnPartial ) break;
}
catch( std::exception& e){
otherExs.push_back( e.what() + errLoc );
_cursors[i].reset( NULL );
conns[i]->done();
break;
}
}
// Go through all the potentially started cursors and finish initializing them or log any errors and
// potentially retry
// TODO: Better error classification would make this easier, errors are indicated in all sorts of ways
// here that we need to trap.
for ( size_t i = 0; i < num; i++ ) {
// log() << "Finishing query for " << cons[i].get()->getHost() << endl;
string errLoc = " @ " + queries[i]._server;
if( ! _cursors[i].raw() || ( ! firstPass && retryQueries.find( i ) == retryQueries.end() ) ){
if( conns[i] ) conns[i].get()->done();
continue;
}
assert( conns[i] );
retryQueries.erase( i );
bool retry = false;
try {
if( ! _cursors[i].raw()->initLazyFinish( retry ) ) {
warning() << "invalid result from " << conns[i]->getHost() << ( retry ? ", retrying" : "" ) << endl;
_cursors[i].reset( NULL );
if( ! retry ){
socketExs.push_back( str::stream() << "error querying server: " << servers[i] );
conns[i]->done();
}
else {
retryQueries.insert( i );
}
continue;
}
}
catch ( MsgAssertionException& e ){
socketExs.push_back( e.what() + errLoc );
_cursors[i].reset( NULL );
conns[i]->done();
continue;
}
catch ( SocketException& e ) {
socketExs.push_back( e.what() + errLoc );
_cursors[i].reset( NULL );
conns[i]->done();
continue;
}
catch( std::exception& e ){
otherExs.push_back( e.what() + errLoc );
_cursors[i].reset( NULL );
conns[i]->done();
continue;
}
try {
_cursors[i].raw()->attach( conns[i].get() ); // this calls done on conn
_checkCursor( _cursors[i].raw() );
finishedQueries++;
}
catch ( StaleConfigException& e ){
// Our stored configuration data is actually stale, we need to reload it
// when we throw our exception
allConfigStale = true;
staleConfigExs.push_back( e.what() + errLoc );
_cursors[i].reset( NULL );
conns[i]->done();
continue;
}
catch( std::exception& e ){
otherExs.push_back( e.what() + errLoc );
_cursors[i].reset( NULL );
conns[i]->done();
continue;
}
}
// Don't exceed our max retries, should not happen
assert( retries < 5 );
}
while( retryQueries.size() > 0 /* something to retry */ &&
( socketExs.size() == 0 || returnPartial ) /* no conn issues */ &&
staleConfigExs.size() == 0 /* no config issues */ &&
otherExs.size() == 0 /* no other issues */);
// Assert that our conns are all closed!
for( vector< shared_ptr<ShardConnection> >::iterator i = conns.begin(); i < conns.end(); ++i ){
assert( ! (*i) || ! (*i)->ok() );
}
// Handle errors we got during initialization.
// If we're returning partial results, we can ignore socketExs, but nothing else
// Log a warning in any case, so we don't lose these messages
bool throwException = ( socketExs.size() > 0 && ! returnPartial ) || staleConfigExs.size() > 0 || otherExs.size() > 0;
if( socketExs.size() > 0 || staleConfigExs.size() > 0 || otherExs.size() > 0 ) {
vector<string> errMsgs;
errMsgs.insert( errMsgs.end(), staleConfigExs.begin(), staleConfigExs.end() );
errMsgs.insert( errMsgs.end(), otherExs.begin(), otherExs.end() );
errMsgs.insert( errMsgs.end(), socketExs.begin(), socketExs.end() );
stringstream errMsg;
errMsg << "could not initialize cursor across all shards because : ";
for( vector<string>::iterator i = errMsgs.begin(); i != errMsgs.end(); i++ ){
if( i != errMsgs.begin() ) errMsg << " :: and :: ";
errMsg << *i;
}
if( throwException && staleConfigExs.size() > 0 )
throw StaleConfigException( _ns , errMsg.str() , ! allConfigStale );
else if( throwException )
throw DBException( errMsg.str(), 14827 );
else
warning() << errMsg.str() << endl;
}
if( retries > 0 )
log() << "successfully finished parallel query after " << retries << " retries" << endl;
}
