QueryResult* processGetMore(const char *ns, int ntoreturn, long long cursorid , CurOp& curop, int pass, bool& exhaust ) { exhaust = false; ClientCursor::Pointer p(cursorid); ClientCursor *cc = p.c(); int bufSize = 512 + sizeof( QueryResult ) + MaxBytesToReturnToClientAtOnce; BufBuilder b( bufSize ); b.skip(sizeof(QueryResult)); int resultFlags = ResultFlag_AwaitCapable; int start = 0; int n = 0; if ( unlikely(!cc) ) { LOGSOME << "getMore: cursorid not found " << ns << " " << cursorid << endl; cursorid = 0; resultFlags = ResultFlag_CursorNotFound; } else { // check for spoofing of the ns such that it does not match the one originally there for the cursor uassert(14833, "auth error", str::equals(ns, cc->ns().c_str())); if ( pass == 0 ) cc->updateSlaveLocation( curop ); int queryOptions = cc->queryOptions(); curop.debug().query = cc->query(); start = cc->pos(); Cursor *c = cc->c(); c->recoverFromYield(); DiskLoc last; scoped_ptr<Projection::KeyOnly> keyFieldsOnly; if ( cc->modifiedKeys() == false && cc->isMultiKey() == false && cc->fields ) keyFieldsOnly.reset( cc->fields->checkKey( cc->indexKeyPattern() ) ); // This manager may be stale, but it's the state of chunking when the cursor was created. ShardChunkManagerPtr manager = cc->getChunkManager(); while ( 1 ) { if ( !c->ok() ) { if ( c->tailable() ) { /* when a tailable cursor hits "EOF", ok() goes false, and current() is null. however advance() can still be retries as a reactivation attempt. when there is new data, it will return true. that's what we are doing here. */ if ( c->advance() ) continue; if( n == 0 && (queryOptions & QueryOption_AwaitData) && pass < 1000 ) { return 0; } break; } p.release(); bool ok = ClientCursor::erase(cursorid); verify(ok); cursorid = 0; cc = 0; break; } // in some cases (clone collection) there won't be a matcher if ( !c->currentMatches() ) { } else if ( manager && ! manager->belongsToMe( cc ) ){ LOG(2) << "cursor skipping document in un-owned chunk: " << c->current() << endl; } else { if( c->getsetdup(c->currLoc()) ) { //out() << " but it's a dup \n"; } else { last = c->currLoc(); n++; if ( keyFieldsOnly ) { fillQueryResultFromObj(b, 0, keyFieldsOnly->hydrate( c->currKey() ) ); } else { BSONObj js = c->current(); // show disk loc should be part of the main query, not in an $or clause, so this should be ok fillQueryResultFromObj(b, cc->fields.get(), js, ( cc->pq.get() && cc->pq->showDiskLoc() ? &last : 0)); } if ( ( ntoreturn && n >= ntoreturn ) || b.len() > MaxBytesToReturnToClientAtOnce ) { c->advance(); cc->incPos( n ); break; } } } c->advance(); if ( ! cc->yieldSometimes( ClientCursor::MaybeCovered ) ) { ClientCursor::erase(cursorid); cursorid = 0; cc = 0; p.deleted(); break; } } if ( cc ) { if ( c->supportYields() ) { ClientCursor::YieldData data; verify( cc->prepareToYield( data ) ); } else { cc->c()->noteLocation(); } cc->mayUpgradeStorage(); cc->storeOpForSlave( last ); exhaust = cc->queryOptions() & QueryOption_Exhaust; } } QueryResult *qr = (QueryResult *) b.buf(); qr->len = b.len(); qr->setOperation(opReply); qr->_resultFlags() = resultFlags; qr->cursorId = cursorid; qr->startingFrom = start; qr->nReturned = n; b.decouple(); return qr; }