/**
* Cleans up one range of orphaned data starting from a range that overlaps or starts at
* 'startingFromKey'. If empty, startingFromKey is the minimum key of the sharded range.
*
* @return CleanupResult_Continue and 'stoppedAtKey' if orphaned range was found and cleaned
* @return CleanupResult_Done if no orphaned ranges remain
* @return CleanupResult_Error and 'errMsg' if an error occurred
*
* If the collection is not sharded, returns CleanupResult_Done.
*/
CleanupResult cleanupOrphanedData( OperationContext* txn,
const NamespaceString& ns,
const BSONObj& startingFromKeyConst,
const WriteConcernOptions& secondaryThrottle,
BSONObj* stoppedAtKey,
string* errMsg ) {
BSONObj startingFromKey = startingFromKeyConst;
CollectionMetadataPtr metadata = shardingState.getCollectionMetadata( ns.toString() );
if ( !metadata || metadata->getKeyPattern().isEmpty() ) {
warning() << "skipping orphaned data cleanup for " << ns.toString()
<< ", collection is not sharded" << endl;
return CleanupResult_Done;
}
BSONObj keyPattern = metadata->getKeyPattern();
if ( !startingFromKey.isEmpty() ) {
if ( !metadata->isValidKey( startingFromKey ) ) {
*errMsg = stream() << "could not cleanup orphaned data, start key "
<< startingFromKey
<< " does not match shard key pattern " << keyPattern;
warning() << *errMsg << endl;
return CleanupResult_Error;
}
}
else {
startingFromKey = metadata->getMinKey();
}
KeyRange orphanRange;
if ( !metadata->getNextOrphanRange( startingFromKey, &orphanRange ) ) {
LOG( 1 ) << "orphaned data cleanup requested for " << ns.toString()
<< " starting from " << startingFromKey
<< ", no orphan ranges remain" << endl;
return CleanupResult_Done;
}
*stoppedAtKey = orphanRange.maxKey;
// We're done with this metadata now, no matter what happens
metadata.reset();
LOG( 1 ) << "orphaned data cleanup requested for " << ns.toString()
<< " starting from " << startingFromKey
<< ", removing next orphan range"
<< " [" << orphanRange.minKey << "," << orphanRange.maxKey << ")"
<< endl;
// Metadata snapshot may be stale now, but deleter checks metadata again in write lock
// before delete.
if ( !getDeleter()->deleteNow( txn,
ns.toString(),
orphanRange.minKey,
orphanRange.maxKey,
keyPattern,
secondaryThrottle,
errMsg ) ) {
warning() << *errMsg << endl;
return CleanupResult_Error;
}
return CleanupResult_Continue;
}
/**
* For a given query, get a runner. The runner could be a SingleSolutionRunner, a
* CachedQueryRunner, or a MultiPlanRunner, depending on the cache/query solver/etc.
*/
Status getRunner(Collection* collection, CanonicalQuery* rawCanonicalQuery,
Runner** out, size_t plannerOptions) {
verify(rawCanonicalQuery);
auto_ptr<CanonicalQuery> canonicalQuery(rawCanonicalQuery);
// This can happen as we're called by internal clients as well.
if (NULL == collection) {
const string& ns = canonicalQuery->ns();
*out = new EOFRunner(canonicalQuery.release(), ns);
return Status::OK();
}
// If we have an _id index we can use the idhack runner.
if (canUseIDHack(*canonicalQuery) && collection->getIndexCatalog()->findIdIndex()) {
*out = new IDHackRunner(collection, canonicalQuery.release());
return Status::OK();
}
// If it's not NULL, we may have indices. Access the catalog and fill out IndexEntry(s)
QueryPlannerParams plannerParams;
IndexCatalog::IndexIterator ii = collection->getIndexCatalog()->getIndexIterator(false);
while (ii.more()) {
const IndexDescriptor* desc = ii.next();
plannerParams.indices.push_back(IndexEntry(desc->keyPattern(),
desc->isMultikey(),
desc->isSparse(),
desc->indexName(),
desc->infoObj()));
}
// If query supports admin hint, filter params.indices by indexes in query settings.
QuerySettings* querySettings = collection->infoCache()->getQuerySettings();
AllowedIndices* allowedIndicesRaw;
// Filter index catalog if admin hint is specified for query.
// Also, signal to planner that application hint should be ignored.
if (querySettings->getAllowedIndices(*canonicalQuery, &allowedIndicesRaw)) {
boost::scoped_ptr<AllowedIndices> allowedIndices(allowedIndicesRaw);
filterAllowedIndexEntries(*allowedIndices, &plannerParams.indices);
plannerParams.adminHintApplied = true;
}
// Tailable: If the query requests tailable the collection must be capped.
if (canonicalQuery->getParsed().hasOption(QueryOption_CursorTailable)) {
if (!collection->isCapped()) {
return Status(ErrorCodes::BadValue,
"error processing query: " + canonicalQuery->toString() +
" tailable cursor requested on non capped collection");
}
// If a sort is specified it must be equal to expectedSort.
const BSONObj expectedSort = BSON("$natural" << 1);
const BSONObj& actualSort = canonicalQuery->getParsed().getSort();
if (!actualSort.isEmpty() && !(actualSort == expectedSort)) {
return Status(ErrorCodes::BadValue,
"error processing query: " + canonicalQuery->toString() +
" invalid sort specified for tailable cursor: "
+ actualSort.toString());
}
}
// Process the planning options.
plannerParams.options = plannerOptions;
if (storageGlobalParams.noTableScan) {
const string& ns = canonicalQuery->ns();
// There are certain cases where we ignore this restriction:
bool ignore = canonicalQuery->getQueryObj().isEmpty()
|| (string::npos != ns.find(".system."))
|| (0 == ns.find("local."));
if (!ignore) {
plannerParams.options |= QueryPlannerParams::NO_TABLE_SCAN;
}
}
if (!(plannerParams.options & QueryPlannerParams::NO_TABLE_SCAN)) {
plannerParams.options |= QueryPlannerParams::INCLUDE_COLLSCAN;
}
// If the caller wants a shard filter, make sure we're actually sharded.
if (plannerParams.options & QueryPlannerParams::INCLUDE_SHARD_FILTER) {
CollectionMetadataPtr collMetadata =
shardingState.getCollectionMetadata(canonicalQuery->ns());
if (collMetadata) {
plannerParams.shardKey = collMetadata->getKeyPattern();
}
else {
// If there's no metadata don't bother w/the shard filter since we won't know what
// the key pattern is anyway...
plannerParams.options &= ~QueryPlannerParams::INCLUDE_SHARD_FILTER;
}
}
// Try to look up a cached solution for the query.
//
// Skip cache look up for non-cacheable queries.
// See PlanCache::shouldCacheQuery()
//
// TODO: Can the cache have negative data about a solution?
CachedSolution* rawCS;
if (PlanCache::shouldCacheQuery(*canonicalQuery) &&
collection->infoCache()->getPlanCache()->get(*canonicalQuery, &rawCS).isOK()) {
// We have a CachedSolution. Have the planner turn it into a QuerySolution.
boost::scoped_ptr<CachedSolution> cs(rawCS);
QuerySolution *qs, *backupQs;
Status status = QueryPlanner::planFromCache(*canonicalQuery, plannerParams, *cs,
&qs, &backupQs);
if (status.isOK()) {
WorkingSet* ws;
PlanStage* root;
verify(StageBuilder::build(*qs, &root, &ws));
CachedPlanRunner* cpr = new CachedPlanRunner(canonicalQuery.release(), qs,
root, ws);
if (NULL != backupQs) {
WorkingSet* backupWs;
PlanStage* backupRoot;
verify(StageBuilder::build(*backupQs, &backupRoot, &backupWs));
cpr->setBackupPlan(backupQs, backupRoot, backupWs);
}
*out = cpr;
return Status::OK();
}
}
plannerParams.options |= QueryPlannerParams::INDEX_INTERSECTION;
plannerParams.options |= QueryPlannerParams::KEEP_MUTATIONS;
vector<QuerySolution*> solutions;
Status status = QueryPlanner::plan(*canonicalQuery, plannerParams, &solutions);
if (!status.isOK()) {
return Status(ErrorCodes::BadValue,
"error processing query: " + canonicalQuery->toString() +
" planner returned error: " + status.reason());
}
/*
for (size_t i = 0; i < solutions.size(); ++i) {
QLOG() << "solution " << i << " is " << solutions[i]->toString() << endl;
}
*/
// We cannot figure out how to answer the query. Should this ever happen?
if (0 == solutions.size()) {
return Status(ErrorCodes::BadValue,
"error processing query: " + canonicalQuery->toString() +
" No query solutions");
}
if (1 == solutions.size()) {
// Only one possible plan. Run it. Build the stages from the solution.
WorkingSet* ws;
PlanStage* root;
verify(StageBuilder::build(*solutions[0], &root, &ws));
// And, run the plan.
*out = new SingleSolutionRunner(canonicalQuery.release(), solutions[0], root, ws);
return Status::OK();
}
else {
// Many solutions. Let the MultiPlanRunner pick the best, update the cache, and so on.
auto_ptr<MultiPlanRunner> mpr(new MultiPlanRunner(canonicalQuery.release()));
for (size_t i = 0; i < solutions.size(); ++i) {
WorkingSet* ws;
PlanStage* root;
if (solutions[i]->cacheData.get()) {
solutions[i]->cacheData->adminHintApplied = plannerParams.adminHintApplied;
}
verify(StageBuilder::build(*solutions[i], &root, &ws));
// Takes ownership of all arguments.
mpr->addPlan(solutions[i], root, ws);
}
*out = mpr.release();
return Status::OK();
}
}
bool mergeChunks(OperationContext* txn,
const NamespaceString& nss,
const BSONObj& minKey,
const BSONObj& maxKey,
const OID& epoch,
string* errMsg) {
//
// Get sharding state up-to-date
//
ConnectionString configLoc = ConnectionString::parse(shardingState.getConfigServer(), *errMsg);
if (!configLoc.isValid()) {
warning() << *errMsg << endl;
return false;
}
//
// Get the distributed lock
//
string whyMessage = stream() << "merging chunks in " << nss.ns() << " from " << minKey << " to "
<< maxKey;
auto scopedDistLock = grid.catalogManager()->getDistLockManager()->lock(nss.ns(), whyMessage);
if (!scopedDistLock.isOK()) {
*errMsg = stream() << "could not acquire collection lock for " << nss.ns()
<< " to merge chunks in [" << minKey << "," << maxKey << ")"
<< causedBy(scopedDistLock.getStatus());
warning() << *errMsg << endl;
return false;
}
//
// We now have the collection lock, refresh metadata to latest version and sanity check
//
ChunkVersion shardVersion;
Status status = shardingState.refreshMetadataNow(txn, nss.ns(), &shardVersion);
if (!status.isOK()) {
*errMsg = str::stream() << "could not merge chunks, failed to refresh metadata for "
<< nss.ns() << causedBy(status.reason());
warning() << *errMsg << endl;
return false;
}
if (epoch.isSet() && shardVersion.epoch() != epoch) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns() << " has changed"
<< " since merge was sent"
<< "(sent epoch : " << epoch.toString()
<< ", current epoch : " << shardVersion.epoch().toString() << ")";
warning() << *errMsg << endl;
return false;
}
CollectionMetadataPtr metadata = shardingState.getCollectionMetadata(nss.ns());
if (!metadata || metadata->getKeyPattern().isEmpty()) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " is not sharded";
warning() << *errMsg << endl;
return false;
}
dassert(metadata->getShardVersion().equals(shardVersion));
if (!metadata->isValidKey(minKey) || !metadata->isValidKey(maxKey)) {
*errMsg = stream() << "could not merge chunks, the range " << rangeToString(minKey, maxKey)
<< " is not valid"
<< " for collection " << nss.ns() << " with key pattern "
<< metadata->getKeyPattern();
warning() << *errMsg << endl;
return false;
}
//
// Get merged chunk information
//
ChunkVersion mergeVersion = metadata->getCollVersion();
mergeVersion.incMinor();
std::vector<ChunkType> chunksToMerge;
ChunkType itChunk;
itChunk.setMin(minKey);
itChunk.setMax(minKey);
itChunk.setNS(nss.ns());
itChunk.setShard(shardingState.getShardName());
while (itChunk.getMax().woCompare(maxKey) < 0 &&
metadata->getNextChunk(itChunk.getMax(), &itChunk)) {
chunksToMerge.push_back(itChunk);
}
if (chunksToMerge.empty()) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " range starting at " << minKey << " and ending at " << maxKey
<< " does not belong to shard " << shardingState.getShardName();
warning() << *errMsg << endl;
return false;
}
//
// Validate the range starts and ends at chunks and has no holes, error if not valid
//
BSONObj firstDocMin = chunksToMerge.front().getMin();
BSONObj firstDocMax = chunksToMerge.front().getMax();
// minKey is inclusive
bool minKeyInRange = rangeContains(firstDocMin, firstDocMax, minKey);
if (!minKeyInRange) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " range starting at " << minKey << " does not belong to shard "
<< shardingState.getShardName();
warning() << *errMsg << endl;
return false;
}
BSONObj lastDocMin = chunksToMerge.back().getMin();
BSONObj lastDocMax = chunksToMerge.back().getMax();
// maxKey is exclusive
bool maxKeyInRange = lastDocMin.woCompare(maxKey) < 0 && lastDocMax.woCompare(maxKey) >= 0;
if (!maxKeyInRange) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " range ending at " << maxKey << " does not belong to shard "
<< shardingState.getShardName();
warning() << *errMsg << endl;
return false;
}
bool validRangeStartKey = firstDocMin.woCompare(minKey) == 0;
bool validRangeEndKey = lastDocMax.woCompare(maxKey) == 0;
if (!validRangeStartKey || !validRangeEndKey) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " does not contain a chunk "
<< (!validRangeStartKey ? "starting at " + minKey.toString() : "")
<< (!validRangeStartKey && !validRangeEndKey ? " or " : "")
<< (!validRangeEndKey ? "ending at " + maxKey.toString() : "");
warning() << *errMsg << endl;
return false;
}
if (chunksToMerge.size() == 1) {
*errMsg = stream() << "could not merge chunks, collection " << nss.ns()
<< " already contains chunk for " << rangeToString(minKey, maxKey);
warning() << *errMsg << endl;
return false;
}
// Look for hole in range
for (size_t i = 1; i < chunksToMerge.size(); ++i) {
if (chunksToMerge[i - 1].getMax().woCompare(chunksToMerge[i].getMin()) != 0) {
*errMsg =
stream() << "could not merge chunks, collection " << nss.ns()
<< " has a hole in the range " << rangeToString(minKey, maxKey) << " at "
<< rangeToString(chunksToMerge[i - 1].getMax(), chunksToMerge[i].getMin());
warning() << *errMsg << endl;
return false;
}
}
//
// Run apply ops command
//
Status applyOpsStatus = runApplyOpsCmd(chunksToMerge, shardVersion, mergeVersion);
if (!applyOpsStatus.isOK()) {
warning() << applyOpsStatus;
return false;
}
//
// Install merged chunk metadata
//
{
ScopedTransaction transaction(txn, MODE_IX);
Lock::DBLock writeLk(txn->lockState(), nss.db(), MODE_IX);
Lock::CollectionLock collLock(txn->lockState(), nss.ns(), MODE_X);
shardingState.mergeChunks(txn, nss.ns(), minKey, maxKey, mergeVersion);
}
//
// Log change
//
BSONObj mergeLogEntry = buildMergeLogEntry(chunksToMerge, shardVersion, mergeVersion);
grid.catalogManager()->logChange(
txn->getClient()->clientAddress(true), "merge", nss.ns(), mergeLogEntry);
return true;
}
/**
* This is called by db/ops/query.cpp. This is the entry point for answering a query.
*/
string newRunQuery(Message& m, QueryMessage& q, CurOp& curop, Message &result) {
// This is a read lock.
Client::ReadContext ctx(q.ns, dbpath);
// Parse, canonicalize, plan, transcribe, and get a runner.
Runner* rawRunner;
Status status = getRunner(q, &rawRunner);
if (!status.isOK()) {
uasserted(17007, "Couldn't process query " + q.query.toString()
+ " why: " + status.reason());
}
verify(NULL != rawRunner);
auto_ptr<Runner> runner(rawRunner);
// We freak out later if this changes before we're done with the query.
const ChunkVersion shardingVersionAtStart = shardingState.getVersion(q.ns);
// We use this a lot below.
const ParsedQuery& pq = runner->getQuery().getParsed();
// TODO: Document why we do this.
replVerifyReadsOk(&pq);
// If this exists, the collection is sharded.
// If it doesn't exist, we can assume we're not sharded.
// If we're sharded, we might encounter data that is not consistent with our sharding state.
// We must ignore this data.
CollectionMetadataPtr collMetadata;
if (!shardingState.needCollectionMetadata(pq.ns())) {
collMetadata = CollectionMetadataPtr();
}
else {
collMetadata = shardingState.getCollectionMetadata(pq.ns());
}
// Run the query.
BufBuilder bb(32768);
bb.skip(sizeof(QueryResult));
// How many results have we obtained from the runner?
int numResults = 0;
// If we're replaying the oplog, we save the last time that we read.
OpTime slaveReadTill;
// Do we save the Runner in a ClientCursor for getMore calls later?
bool saveClientCursor = false;
BSONObj obj;
// TODO: Differentiate EOF from error.
while (runner->getNext(&obj)) {
// If we're sharded make sure that we don't return any data that hasn't been migrated
// off of our shared yet.
if (collMetadata) {
// This information can change if we yield and as such we must make sure to re-fetch
// it if we yield.
KeyPattern kp(collMetadata->getKeyPattern());
// This performs excessive BSONObj creation but that's OK for now.
if (!collMetadata->keyBelongsToMe(kp.extractSingleKey(obj))) { continue; }
}
// Add result to output buffer.
bb.appendBuf((void*)obj.objdata(), obj.objsize());
// Count the result.
++numResults;
// Possibly note slave's position in the oplog.
if (pq.hasOption(QueryOption_OplogReplay)) {
BSONElement e = obj["ts"];
if (Date == e.type() || Timestamp == e.type()) {
slaveReadTill = e._opTime();
}
}
// TODO: only one type of 2d search doesn't support this. We need a way to pull it out
// of CanonicalQuery. :(
const bool supportsGetMore = true;
const bool isExplain = pq.isExplain();
if (isExplain && pq.enoughForExplain(numResults)) {
break;
}
else if (!supportsGetMore && (pq.enough(numResults)
|| bb.len() >= MaxBytesToReturnToClientAtOnce)) {
break;
}
else if (pq.enoughForFirstBatch(numResults, bb.len())) {
// If only one result requested assume it's a findOne() and don't save the cursor.
if (pq.wantMore() && 1 != pq.getNumToReturn()) {
saveClientCursor = true;
}
break;
}
}
// TODO: Stage creation can set tailable depending on what's in the parsed query. We have
// the full parsed query available during planning...set it there.
//
// TODO: If we're tailable we want to save the client cursor. Make sure we do this later.
//if (pq.hasOption(QueryOption_CursorTailable) && pq.getNumToReturn() != 1) { ... }
// TODO(greg): This will go away soon.
if (!shardingState.getVersion(pq.ns()).isWriteCompatibleWith(shardingVersionAtStart)) {
// if the version changed during the query we might be missing some data and its safe to
// send this as mongos can resend at this point
throw SendStaleConfigException(pq.ns(), "version changed during initial query",
shardingVersionAtStart,
shardingState.getVersion(pq.ns()));
}
long long ccId = 0;
if (saveClientCursor) {
// Allocate a new ClientCursor.
ClientCursorHolder ccHolder;
ccHolder.reset(new ClientCursor(runner.get()));
ccId = ccHolder->cursorid();
// We won't use the runner until it's getMore'd.
runner->saveState();
// ClientCursor takes ownership of runner. Release to make sure it's not deleted.
runner.release();
if (pq.hasOption(QueryOption_OplogReplay) && !slaveReadTill.isNull()) {
ccHolder->slaveReadTill(slaveReadTill);
}
if (pq.hasOption(QueryOption_Exhaust)) {
curop.debug().exhaust = true;
}
// Set attributes for getMore.
ccHolder->setCollMetadata(collMetadata);
ccHolder->setPos(numResults);
// If the query had a time limit, remaining time is "rolled over" to the cursor (for
// use by future getmore ops).
ccHolder->setLeftoverMaxTimeMicros(curop.getRemainingMaxTimeMicros());
// Give up our reference to the CC.
ccHolder.release();
}
// Add the results from the query into the output buffer.
result.appendData(bb.buf(), bb.len());
bb.decouple();
// Fill out the output buffer's header.
QueryResult* qr = static_cast<QueryResult*>(result.header());
qr->cursorId = ccId;
curop.debug().cursorid = (0 == ccId ? -1 : ccId);
qr->setResultFlagsToOk();
qr->setOperation(opReply);
qr->startingFrom = 0;
qr->nReturned = numResults;
// TODO: nscanned is bogus.
// curop.debug().nscanned = ( cursor ? cursor->nscanned() : 0LL );
curop.debug().ntoskip = pq.getSkip();
curop.debug().nreturned = numResults;
// curop.debug().exhaust is set above.
return curop.debug().exhaust ? pq.ns() : "";
}
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;
}
/**
* Also called by db/ops/query.cpp. This is the new getMore entry point.
*/
QueryResult* newGetMore(const char* ns, int ntoreturn, long long cursorid, CurOp& curop,
int pass, bool& exhaust, bool* isCursorAuthorized) {
exhaust = false;
int bufSize = 512 + sizeof(QueryResult) + MaxBytesToReturnToClientAtOnce;
BufBuilder bb(bufSize);
bb.skip(sizeof(QueryResult));
// This is a read lock. TODO: There is a cursor flag for not needing this. Do we care?
Client::ReadContext ctx(ns);
// TODO: Document.
replVerifyReadsOk();
ClientCursorPin ccPin(cursorid);
ClientCursor* cc = ccPin.c();
// These are set in the QueryResult msg we return.
int resultFlags = ResultFlag_AwaitCapable;
int numResults = 0;
int startingResult = 0;
if (NULL == cc) {
cursorid = 0;
resultFlags = ResultFlag_CursorNotFound;
}
else {
// Quote: check for spoofing of the ns such that it does not match the one originally
// there for the cursor
uassert(17011, "auth error", str::equals(ns, cc->ns().c_str()));
*isCursorAuthorized = true;
// TODO: fail point?
// If the operation that spawned this cursor had a time limit set, apply leftover
// time to this getmore.
curop.setMaxTimeMicros(cc->getLeftoverMaxTimeMicros());
// TODO:
// curop.debug().query = BSONForQuery
// curop.setQuery(curop.debug().query);
// TODO: What is pass?
if (0 == pass) { cc->updateSlaveLocation(curop); }
CollectionMetadataPtr collMetadata = cc->getCollMetadata();
// If we're replaying the oplog, we save the last time that we read.
OpTime slaveReadTill;
startingResult = cc->pos();
Runner* runner = cc->getRunner();
const ParsedQuery& pq = runner->getQuery().getParsed();
// Get results out of the runner.
// TODO: There may be special handling required for tailable cursors?
runner->restoreState();
BSONObj obj;
// TODO: Differentiate EOF from error.
while (runner->getNext(&obj)) {
// If we're sharded make sure that we don't return any data that hasn't been
// migrated off of our shard yet.
if (collMetadata) {
KeyPattern kp(collMetadata->getKeyPattern());
if (!collMetadata->keyBelongsToMe(kp.extractSingleKey(obj))) { continue; }
}
// Add result to output buffer.
bb.appendBuf((void*)obj.objdata(), obj.objsize());
// Count the result.
++numResults;
// Possibly note slave's position in the oplog.
if (pq.hasOption(QueryOption_OplogReplay)) {
BSONElement e = obj["ts"];
if (Date == e.type() || Timestamp == e.type()) {
slaveReadTill = e._opTime();
}
}
if ((numResults && numResults >= ntoreturn)
|| bb.len() > MaxBytesToReturnToClientAtOnce) {
break;
}
}
cc->incPos(numResults);
runner->saveState();
// Possibly note slave's position in the oplog.
if (pq.hasOption(QueryOption_OplogReplay) && !slaveReadTill.isNull()) {
cc->slaveReadTill(slaveReadTill);
}
exhaust = pq.hasOption(QueryOption_Exhaust);
// If the getmore had a time limit, remaining time is "rolled over" back to the
// cursor (for use by future getmore ops).
cc->setLeftoverMaxTimeMicros( curop.getRemainingMaxTimeMicros() );
}
QueryResult* qr = reinterpret_cast<QueryResult*>(bb.buf());
qr->len = bb.len();
qr->setOperation(opReply);
qr->_resultFlags() = resultFlags;
qr->cursorId = cursorid;
qr->startingFrom = startingResult;
qr->nReturned = numResults;
bb.decouple();
return qr;
}
/**
* This is called by db/ops/query.cpp. This is the entry point for answering a query.
*/
string newRunQuery(Message& m, QueryMessage& q, CurOp& curop, Message &result) {
// This is a read lock.
Client::ReadContext ctx(q.ns, dbpath);
// Parse, canonicalize, plan, transcribe, and get a runner.
Runner* rawRunner;
CanonicalQuery* cq;
Status status = getRunner(q, &rawRunner, &cq);
if (!status.isOK()) {
uasserted(17007, "Couldn't process query " + q.query.toString()
+ " why: " + status.reason());
}
verify(NULL != rawRunner);
auto_ptr<Runner> runner(rawRunner);
log() << "Running query on new system: " << cq->toString();
// We freak out later if this changes before we're done with the query.
const ChunkVersion shardingVersionAtStart = shardingState.getVersion(q.ns);
// We use this a lot below.
const LiteParsedQuery& pq = cq->getParsed();
// TODO: Remove when impl'd
if (pq.hasOption(QueryOption_OplogReplay)) {
warning() << "haven't implemented findingstartcursor yet\n";
}
// Handle query option $maxTimeMS (not used with commands).
curop.setMaxTimeMicros(static_cast<unsigned long long>(pq.getMaxTimeMS()) * 1000);
killCurrentOp.checkForInterrupt(); // May trigger maxTimeAlwaysTimeOut fail point.
// uassert if we are not on a primary, and not a secondary with SlaveOk query parameter set.
replVerifyReadsOk(&pq);
// If this exists, the collection is sharded.
// If it doesn't exist, we can assume we're not sharded.
// If we're sharded, we might encounter data that is not consistent with our sharding state.
// We must ignore this data.
CollectionMetadataPtr collMetadata;
if (!shardingState.needCollectionMetadata(pq.ns())) {
collMetadata = CollectionMetadataPtr();
}
else {
collMetadata = shardingState.getCollectionMetadata(pq.ns());
}
// Run the query.
// bb is used to hold query results
// this buffer should contain either requested documents per query or
// explain information, but not both
BufBuilder bb(32768);
bb.skip(sizeof(QueryResult));
// How many results have we obtained from the runner?
int numResults = 0;
// If we're replaying the oplog, we save the last time that we read.
OpTime slaveReadTill;
// Do we save the Runner in a ClientCursor for getMore calls later?
bool saveClientCursor = false;
// We turn on auto-yielding for the runner here. The runner registers itself with the
// active runners list in ClientCursor.
ClientCursor::registerRunner(runner.get());
runner->setYieldPolicy(Runner::YIELD_AUTO);
auto_ptr<DeregisterEvenIfUnderlyingCodeThrows> safety(
new DeregisterEvenIfUnderlyingCodeThrows(runner.get()));
BSONObj obj;
Runner::RunnerState state;
// set this outside loop. we will need to use this both within loop and when deciding
// to fill in explain information
const bool isExplain = pq.isExplain();
while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
// If we're sharded make sure that we don't return any data that hasn't been migrated
// off of our shared yet.
if (collMetadata) {
// This information can change if we yield and as such we must make sure to re-fetch
// it if we yield.
KeyPattern kp(collMetadata->getKeyPattern());
// This performs excessive BSONObj creation but that's OK for now.
if (!collMetadata->keyBelongsToMe(kp.extractSingleKey(obj))) { continue; }
}
// Add result to output buffer. This is unnecessary if explain info is requested
if (!isExplain) {
bb.appendBuf((void*)obj.objdata(), obj.objsize());
}
// Count the result.
++numResults;
// Possibly note slave's position in the oplog.
if (pq.hasOption(QueryOption_OplogReplay)) {
BSONElement e = obj["ts"];
if (Date == e.type() || Timestamp == e.type()) {
slaveReadTill = e._opTime();
}
}
// TODO: only one type of 2d search doesn't support this. We need a way to pull it out
// of CanonicalQuery. :(
const bool supportsGetMore = true;
if (isExplain) {
if (enoughForExplain(pq, numResults)) {
break;
}
}
else if (!supportsGetMore && (enough(pq, numResults)
|| bb.len() >= MaxBytesToReturnToClientAtOnce)) {
break;
}
else if (enoughForFirstBatch(pq, numResults, bb.len())) {
// If only one result requested assume it's a findOne() and don't save the cursor.
if (pq.wantMore() && 1 != pq.getNumToReturn()) {
saveClientCursor = true;
}
break;
}
}
// If we cache the runner later, we want to deregister it as it receives notifications
// anyway by virtue of being cached.
//
// If we don't cache the runner later, we are deleting it, so it must be deregistered.
//
// So, no matter what, deregister the runner.
safety.reset();
// Caller expects exceptions thrown in certain cases:
// * in-memory sort using too much RAM.
if (Runner::RUNNER_ERROR == state) {
uasserted(17144, "Runner error, memory limit for sort probably exceeded");
}
// Why save a dead runner?
if (Runner::RUNNER_DEAD == state) {
saveClientCursor = false;
}
else if (pq.hasOption(QueryOption_CursorTailable) && (1 != pq.getNumToReturn())) {
// If pq.hasOption(tailable) the only plan the planner will output is a collscan with
// tailable set.
saveClientCursor = true;
}
// TODO(greg): This will go away soon.
if (!shardingState.getVersion(pq.ns()).isWriteCompatibleWith(shardingVersionAtStart)) {
// if the version changed during the query we might be missing some data and its safe to
// send this as mongos can resend at this point
throw SendStaleConfigException(pq.ns(), "version changed during initial query",
shardingVersionAtStart,
shardingState.getVersion(pq.ns()));
}
long long ccId = 0;
if (saveClientCursor) {
// We won't use the runner until it's getMore'd.
runner->saveState();
// Allocate a new ClientCursor. We don't have to worry about leaking it as it's
// inserted into a global map by its ctor.
ClientCursor* cc = new ClientCursor(runner.get(), cq->getParsed().getOptions(),
cq->getParsed().getFilter());
ccId = cc->cursorid();
log() << "caching runner with cursorid " << ccId
<< " after returning " << numResults << " results" << endl;
// ClientCursor takes ownership of runner. Release to make sure it's not deleted.
runner.release();
// TODO document
if (pq.hasOption(QueryOption_OplogReplay) && !slaveReadTill.isNull()) {
cc->slaveReadTill(slaveReadTill);
}
// TODO document
if (pq.hasOption(QueryOption_Exhaust)) {
curop.debug().exhaust = true;
}
// Set attributes for getMore.
cc->setCollMetadata(collMetadata);
cc->setPos(numResults);
// If the query had a time limit, remaining time is "rolled over" to the cursor (for
// use by future getmore ops).
cc->setLeftoverMaxTimeMicros(curop.getRemainingMaxTimeMicros());
}
// append explain information to query results
if (isExplain) {
BSONObjBuilder bob;
bob.append("n", numResults);
BSONObj obj = bob.done();
bb.appendBuf((void*)obj.objdata(), obj.objsize());
// The explain output is actually a result.
numResults = 1;
}
// Add the results from the query into the output buffer.
result.appendData(bb.buf(), bb.len());
bb.decouple();
// Fill out the output buffer's header.
QueryResult* qr = static_cast<QueryResult*>(result.header());
qr->cursorId = ccId;
curop.debug().cursorid = (0 == ccId ? -1 : ccId);
qr->setResultFlagsToOk();
qr->setOperation(opReply);
qr->startingFrom = 0;
qr->nReturned = numResults;
// TODO: nscanned is bogus.
// curop.debug().nscanned = ( cursor ? cursor->nscanned() : 0LL );
curop.debug().ntoskip = pq.getSkip();
curop.debug().nreturned = numResults;
// curop.debug().exhaust is set above.
return curop.debug().exhaust ? pq.ns() : "";
}
/**
* Also called by db/ops/query.cpp. This is the new getMore entry point.
*/
QueryResult* newGetMore(const char* ns, int ntoreturn, long long cursorid, CurOp& curop,
int pass, bool& exhaust, bool* isCursorAuthorized) {
exhaust = false;
int bufSize = 512 + sizeof(QueryResult) + MaxBytesToReturnToClientAtOnce;
BufBuilder bb(bufSize);
bb.skip(sizeof(QueryResult));
// This is a read lock. TODO: There is a cursor flag for not needing this. Do we care?
Client::ReadContext ctx(ns);
//log() << "running getMore in new system, cursorid " << cursorid << endl;
// This checks to make sure the operation is allowed on a replicated node. Since we are not
// passing in a query object (necessary to check SlaveOK query option), the only state where
// reads are allowed is PRIMARY (or master in master/slave). This function uasserts if
// reads are not okay.
replVerifyReadsOk();
// A pin performs a CC lookup and if there is a CC, increments the CC's pin value so it
// doesn't time out. Also informs ClientCursor that there is somebody actively holding the
// CC, so don't delete it.
ClientCursorPin ccPin(cursorid);
ClientCursor* cc = ccPin.c();
// These are set in the QueryResult msg we return.
int resultFlags = ResultFlag_AwaitCapable;
int numResults = 0;
int startingResult = 0;
if (NULL == cc) {
cursorid = 0;
resultFlags = ResultFlag_CursorNotFound;
}
else {
// Quote: check for spoofing of the ns such that it does not match the one originally
// there for the cursor
uassert(17011, "auth error", str::equals(ns, cc->ns().c_str()));
*isCursorAuthorized = true;
// TODO: fail point?
// If the operation that spawned this cursor had a time limit set, apply leftover
// time to this getmore.
curop.setMaxTimeMicros(cc->getLeftoverMaxTimeMicros());
killCurrentOp.checkForInterrupt(); // May trigger maxTimeAlwaysTimeOut fail point.
// TODO:
// curop.debug().query = BSONForQuery
// curop.setQuery(curop.debug().query);
// TODO: What is pass?
if (0 == pass) { cc->updateSlaveLocation(curop); }
CollectionMetadataPtr collMetadata = cc->getCollMetadata();
// If we're replaying the oplog, we save the last time that we read.
OpTime slaveReadTill;
// What number result are we starting at? Used to fill out the reply.
startingResult = cc->pos();
// What gives us results.
Runner* runner = cc->getRunner();
const int queryOptions = cc->queryOptions();
// Get results out of the runner.
runner->restoreState();
BSONObj obj;
Runner::RunnerState state;
while (Runner::RUNNER_ADVANCED == (state = runner->getNext(&obj, NULL))) {
// If we're sharded make sure that we don't return any data that hasn't been
// migrated off of our shard yet.
if (collMetadata) {
KeyPattern kp(collMetadata->getKeyPattern());
if (!collMetadata->keyBelongsToMe(kp.extractSingleKey(obj))) { continue; }
}
// Add result to output buffer.
bb.appendBuf((void*)obj.objdata(), obj.objsize());
// Count the result.
++numResults;
// Possibly note slave's position in the oplog.
if (queryOptions & QueryOption_OplogReplay) {
BSONElement e = obj["ts"];
if (Date == e.type() || Timestamp == e.type()) {
slaveReadTill = e._opTime();
}
}
if ((numResults && numResults >= ntoreturn)
|| bb.len() > MaxBytesToReturnToClientAtOnce) {
break;
}
}
if (Runner::RUNNER_EOF == state
&& 0 == numResults
&& (queryOptions & QueryOption_CursorTailable)
&& (queryOptions & QueryOption_AwaitData)
&& (pass < 1000)) {
// If the cursor is tailable we don't kill it if it's eof. We let it try to get
// data some # of times first.
return 0;
}
else if (Runner::RUNNER_DEAD == state || Runner::RUNNER_EOF == state) {
ccPin.free();
// cc is now invalid, as is the runner
cursorid = 0;
cc = NULL;
}
else {
// Continue caching the ClientCursor.
cc->incPos(numResults);
runner->saveState();
// Possibly note slave's position in the oplog.
if ((queryOptions & QueryOption_OplogReplay) && !slaveReadTill.isNull()) {
cc->slaveReadTill(slaveReadTill);
}
exhaust = (queryOptions & QueryOption_Exhaust);
// If the getmore had a time limit, remaining time is "rolled over" back to the
// cursor (for use by future getmore ops).
cc->setLeftoverMaxTimeMicros( curop.getRemainingMaxTimeMicros() );
}
}
QueryResult* qr = reinterpret_cast<QueryResult*>(bb.buf());
qr->len = bb.len();
qr->setOperation(opReply);
qr->_resultFlags() = resultFlags;
qr->cursorId = cursorid;
qr->startingFrom = startingResult;
qr->nReturned = numResults;
bb.decouple();
return qr;
}
/**
* For a given query, get a runner. The runner could be a SingleSolutionRunner, a
* CachedQueryRunner, or a MultiPlanRunner, depending on the cache/query solver/etc.
*/
Status getRunner(CanonicalQuery* rawCanonicalQuery, Runner** out, size_t plannerOptions) {
verify(rawCanonicalQuery);
auto_ptr<CanonicalQuery> canonicalQuery(rawCanonicalQuery);
// Try to look up a cached solution for the query.
// TODO: Can the cache have negative data about a solution?
PlanCache* localCache = PlanCache::get(canonicalQuery->ns());
if (NULL != localCache) {
CachedSolution* cs = localCache->get(*canonicalQuery);
if (NULL != cs) {
// We have a cached solution. Hand the canonical query and cached solution off to
// the cached plan runner, which takes ownership of both.
WorkingSet* ws;
PlanStage* root;
verify(StageBuilder::build(*cs->solution, &root, &ws));
*out = new CachedPlanRunner(canonicalQuery.release(), cs, root, ws);
return Status::OK();
}
}
// No entry in cache for the query. We have to solve the query ourself.
// Get the indices that we could possibly use.
Database* db = cc().database();
verify( db );
Collection* collection = db->getCollection( canonicalQuery->ns() );
// This can happen as we're called by internal clients as well.
if (NULL == collection) {
const string& ns = canonicalQuery->ns();
*out = new EOFRunner(canonicalQuery.release(), ns);
return Status::OK();
}
// If we have an _id index we can use the idhack runner.
if (canUseIDHack(*canonicalQuery) && collection->getIndexCatalog()->findIdIndex()) {
*out = new IDHackRunner(collection, canonicalQuery.release());
return Status::OK();
}
// If it's not NULL, we may have indices. Access the catalog and fill out IndexEntry(s)
QueryPlannerParams plannerParams;
for (int i = 0; i < collection->getIndexCatalog()->numIndexesReady(); ++i) {
IndexDescriptor* desc = collection->getIndexCatalog()->getDescriptor( i );
plannerParams.indices.push_back(IndexEntry(desc->keyPattern(),
desc->isMultikey(),
desc->isSparse(),
desc->indexName()));
}
// Tailable: If the query requests tailable the collection must be capped.
if (canonicalQuery->getParsed().hasOption(QueryOption_CursorTailable)) {
if (!collection->isCapped()) {
return Status(ErrorCodes::BadValue,
"tailable cursor requested on non capped collection");
}
// If a sort is specified it must be equal to expectedSort.
const BSONObj expectedSort = BSON("$natural" << 1);
const BSONObj& actualSort = canonicalQuery->getParsed().getSort();
if (!actualSort.isEmpty() && !(actualSort == expectedSort)) {
return Status(ErrorCodes::BadValue,
"invalid sort specified for tailable cursor: "
+ actualSort.toString());
}
}
// Process the planning options.
plannerParams.options = plannerOptions;
if (storageGlobalParams.noTableScan) {
const string& ns = canonicalQuery->ns();
// There are certain cases where we ignore this restriction:
bool ignore = canonicalQuery->getQueryObj().isEmpty()
|| (string::npos != ns.find(".system."))
|| (0 == ns.find("local."));
if (!ignore) {
plannerParams.options |= QueryPlannerParams::NO_TABLE_SCAN;
}
}
if (!(plannerParams.options & QueryPlannerParams::NO_TABLE_SCAN)) {
plannerParams.options |= QueryPlannerParams::INCLUDE_COLLSCAN;
}
// If the caller wants a shard filter, make sure we're actually sharded.
if (plannerParams.options & QueryPlannerParams::INCLUDE_SHARD_FILTER) {
CollectionMetadataPtr collMetadata = shardingState.getCollectionMetadata(canonicalQuery->ns());
if (collMetadata) {
plannerParams.shardKey = collMetadata->getKeyPattern();
}
else {
// If there's no metadata don't bother w/the shard filter since we won't know what
// the key pattern is anyway...
plannerParams.options &= ~QueryPlannerParams::INCLUDE_SHARD_FILTER;
}
}
vector<QuerySolution*> solutions;
QueryPlanner::plan(*canonicalQuery, plannerParams, &solutions);
/*
for (size_t i = 0; i < solutions.size(); ++i) {
QLOG() << "solution " << i << " is " << solutions[i]->toString() << endl;
}
*/
// We cannot figure out how to answer the query. Should this ever happen?
if (0 == solutions.size()) {
return Status(ErrorCodes::BadValue, "No query solutions");
}
if (1 == solutions.size()) {
// Only one possible plan. Run it. Build the stages from the solution.
WorkingSet* ws;
PlanStage* root;
verify(StageBuilder::build(*solutions[0], &root, &ws));
// And, run the plan.
*out = new SingleSolutionRunner(canonicalQuery.release(), solutions[0], root, ws);
return Status::OK();
}
else {
// Many solutions. Let the MultiPlanRunner pick the best, update the cache, and so on.
auto_ptr<MultiPlanRunner> mpr(new MultiPlanRunner(canonicalQuery.release()));
for (size_t i = 0; i < solutions.size(); ++i) {
WorkingSet* ws;
PlanStage* root;
verify(StageBuilder::build(*solutions[i], &root, &ws));
// Takes ownership of all arguments.
mpr->addPlan(solutions[i], root, ws);
}
*out = mpr.release();
return Status::OK();
}
}
QueryResult* processGetMore(const char* ns,
int ntoreturn,
long long cursorid,
CurOp& curop,
int pass,
bool& exhaust,
bool* isCursorAuthorized ) {
if (isNewQueryFrameworkEnabled()) {
return newGetMore(ns, ntoreturn, cursorid, curop, pass, exhaust, isCursorAuthorized);
}
exhaust = false;
int bufSize = 512 + sizeof( QueryResult ) + MaxBytesToReturnToClientAtOnce;
BufBuilder b( bufSize );
b.skip(sizeof(QueryResult));
int resultFlags = ResultFlag_AwaitCapable;
int start = 0;
int n = 0;
scoped_ptr<Client::ReadContext> ctx(new Client::ReadContext(ns));
// call this readlocked so state can't change
replVerifyReadsOk();
ClientCursorPin p(cursorid);
ClientCursor *cc = p.c();
if ( unlikely(!cc) ) {
LOGSOME << "getMore: cursorid not found " << ns << " " << cursorid << endl;
cursorid = 0;
resultFlags = ResultFlag_CursorNotFound;
}
else {
// Some internal users create a ClientCursor with a Runner. Don't crash if this
// happens. Instead, hand them off to the new framework.
if (NULL != cc->getRunner()) {
p.release();
return newGetMore(ns, ntoreturn, cursorid, curop, pass, exhaust, isCursorAuthorized);
}
// 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()));
*isCursorAuthorized = true;
// This must be done after auth check to ensure proper cleanup.
uassert(16951, "failing getmore due to set failpoint",
!MONGO_FAIL_POINT(getMoreError));
// If the operation that spawned this cursor had a time limit set, apply leftover
// time to this getmore.
curop.setMaxTimeMicros( cc->getLeftoverMaxTimeMicros() );
if ( pass == 0 )
cc->updateSlaveLocation( curop );
int queryOptions = cc->queryOptions();
curop.debug().query = cc->query();
curop.setQuery( cc->query() );
start = cc->pos();
Cursor *c = cc->c();
if (!c->requiresLock()) {
// make sure it won't be destroyed under us
fassert(16952, !c->shouldDestroyOnNSDeletion());
fassert(16953, !c->supportYields());
ctx.reset(); // unlocks
}
c->recoverFromYield();
DiskLoc last;
// This metadata may be stale, but it's the state of chunking when the cursor was
// created.
CollectionMetadataPtr metadata = cc->getCollMetadata();
KeyPattern keyPattern( metadata ? metadata->getKeyPattern() : BSONObj() );
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;
}
MatchDetails details;
if ( cc->fields && cc->fields->getArrayOpType() == Projection::ARRAY_OP_POSITIONAL ) {
// field projection specified, and contains an array operator
details.requestElemMatchKey();
}
// in some cases (clone collection) there won't be a matcher
if ( !c->currentMatches( &details ) ) {
}
else if ( metadata && !metadata->keyBelongsToMe( extractKey(c, keyPattern ) ) ) {
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++;
// Fill out the fields requested by the query.
const Projection::KeyOnly *keyFieldsOnly = c->keyFieldsOnly();
if ( keyFieldsOnly ) {
fillQueryResultFromObj( b, 0, keyFieldsOnly->hydrate(
c->currKey() ), &details );
}
else {
DiskLoc loc = c->currLoc();
fillQueryResultFromObj( b, cc->fields.get(), c->current(), &details,
( ( cc->pq.get() && cc->pq->showDiskLoc() ) ? &loc : 0 ) );
}
if ( ( ntoreturn && n >= ntoreturn ) || b.len() > MaxBytesToReturnToClientAtOnce ) {
c->advance();
cc->incPos( n );
break;
}
}
}
c->advance();
if ( ! cc->yieldSometimes( ( c->ok() && c->keyFieldsOnly() ) ?
ClientCursor::DontNeed : ClientCursor::WillNeed ) ) {
ClientCursor::erase(cursorid);
cursorid = 0;
cc = 0;
break;
}
}
if ( cc ) {
if ( c->supportYields() ) {
ClientCursor::YieldData data;
verify( cc->prepareToYield( data ) );
}
else {
cc->c()->noteLocation();
}
cc->storeOpForSlave( last );
exhaust = cc->queryOptions() & QueryOption_Exhaust;
// If the getmore had a time limit, remaining time is "rolled over" back to the
// cursor (for use by future getmore ops).
cc->setLeftoverMaxTimeMicros( curop.getRemainingMaxTimeMicros() );
}
}
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;
}
