bool Helpers::findById(Client& c, const char *ns, BSONObj query, BSONObj& result ,
bool* nsFound , bool* indexFound ) {
Lock::assertAtLeastReadLocked(ns);
Database *database = c.database();
verify( database );
Collection* collection = database->getCollection( ns );
if ( !collection ) {
return false;
}
if ( nsFound )
*nsFound = true;
IndexCatalog* catalog = collection->getIndexCatalog();
const IndexDescriptor* desc = catalog->findIdIndex();
if ( !desc )
return false;
if ( indexFound )
*indexFound = 1;
BtreeBasedAccessMethod* accessMethod = catalog->getBtreeBasedIndex( desc );
DiskLoc loc = accessMethod->findSingle( query["_id"].wrap() );
if ( loc.isNull() )
return false;
result = collection->docFor( loc );
return true;
}
DiskLoc Helpers::findById(Collection* collection, const BSONObj& idquery) {
verify(collection);
IndexCatalog* catalog = collection->getIndexCatalog();
const IndexDescriptor* desc = catalog->findIdIndex();
uassert(13430, "no _id index", desc);
BtreeBasedAccessMethod* accessMethod = catalog->getBtreeBasedIndex( desc );
return accessMethod->findSingle( idquery["_id"].wrap() );
}
Runner::RunnerState IDHackRunner::getNext(BSONObj* objOut, DiskLoc* dlOut) {
if (_killed) { return Runner::RUNNER_DEAD; }
if (_done) { return Runner::RUNNER_EOF; }
// Use the index catalog to get the id index.
IndexCatalog* catalog = _collection->getIndexCatalog();
// Find the index we use.
const IndexDescriptor* idDesc = catalog->findIdIndex();
if (NULL == idDesc) {
_done = true;
return Runner::RUNNER_EOF;
}
BtreeBasedAccessMethod* accessMethod = catalog->getBtreeBasedIndex( idDesc );
BSONObj key = _query->getQueryObj()["_id"].wrap();
// Look up the key by going directly to the Btree.
DiskLoc loc = accessMethod->findSingle( key );
_done = true;
// Key not found.
if (loc.isNull()) {
return Runner::RUNNER_EOF;
}
// Set out parameters and note that we're done w/lookup.
if (NULL != objOut) {
Record* record = loc.rec();
// If the record isn't in memory...
if (!Record::likelyInPhysicalMemory(record->dataNoThrowing())) {
// And we're allowed to yield ourselves...
if (Runner::YIELD_AUTO == _policy) {
// Note what we're yielding to fetch so that we don't crash if the loc is
// deleted during a yield.
_locFetching = loc;
// Yield. TODO: Do we want to bother yielding if micros < 0?
int micros = ClientCursor::suggestYieldMicros();
ClientCursor::staticYield(micros, "", record);
// This can happen when we're yielded for various reasons (e.g. db/idx dropped).
if (_killed) {
return Runner::RUNNER_DEAD;
}
}
}
// Either the data was in memory or we paged it in.
*objOut = loc.obj();
// If we're sharded make sure the key belongs to us. We need the object to do this.
if (shardingState.needCollectionMetadata(_query->ns())) {
CollectionMetadataPtr m = shardingState.getCollectionMetadata(_query->ns());
if (m) {
KeyPattern kp(m->getKeyPattern());
if (!m->keyBelongsToMe( kp.extractSingleKey(*objOut))) {
// We have something with a matching _id but it doesn't belong to me.
return Runner::RUNNER_EOF;
}
}
}
// If there is a projection...
if (NULL != _query->getProj()) {
// Create something to execute it.
auto_ptr<ProjectionExec> projExec(new ProjectionExec(_query->getParsed().getProj(),
_query->root()));
projExec->transform(*objOut, objOut);
}
}
// Return the DiskLoc if the caller wants it.
if (NULL != dlOut) {
*dlOut = loc;
}
return Runner::RUNNER_ADVANCED;
}