void Strategy::queryOp(OperationContext* txn, Request& request) {
verify(!NamespaceString(request.getns()).isCommand());
Timer queryTimer;
globalOpCounters.gotQuery();
QueryMessage q(request.d());
NamespaceString ns(q.ns);
ClientBasic* client = txn->getClient();
AuthorizationSession* authSession = AuthorizationSession::get(client);
Status status = authSession->checkAuthForFind(ns, false);
audit::logQueryAuthzCheck(client, ns, q.query, status.code());
uassertStatusOK(status);
LOG(3) << "query: " << q.ns << " " << q.query << " ntoreturn: " << q.ntoreturn
<< " options: " << q.queryOptions;
if (q.ntoreturn == 1 && strstr(q.ns, ".$cmd"))
throw UserException(8010, "something is wrong, shouldn't see a command here");
if (q.queryOptions & QueryOption_Exhaust) {
uasserted(18526,
string("the 'exhaust' query option is invalid for mongos queries: ") + q.ns +
" " + q.query.toString());
}
// Spigot which controls whether OP_QUERY style find on mongos uses the new ClusterClientCursor
// code path.
// TODO: Delete the spigot and always use the new code.
if (useClusterClientCursor) {
// Determine the default read preference mode based on the value of the slaveOk flag.
ReadPreference readPreferenceOption = (q.queryOptions & QueryOption_SlaveOk)
? ReadPreference::SecondaryPreferred
: ReadPreference::PrimaryOnly;
ReadPreferenceSetting readPreference(readPreferenceOption, TagSet());
BSONElement rpElem;
auto readPrefExtractStatus = bsonExtractTypedField(
q.query, LiteParsedQuery::kWrappedReadPrefField, mongo::Object, &rpElem);
if (readPrefExtractStatus.isOK()) {
auto parsedRps = ReadPreferenceSetting::fromBSON(rpElem.Obj());
uassertStatusOK(parsedRps.getStatus());
readPreference = parsedRps.getValue();
} else if (readPrefExtractStatus != ErrorCodes::NoSuchKey) {
uassertStatusOK(readPrefExtractStatus);
}
auto canonicalQuery = CanonicalQuery::canonicalize(q, WhereCallbackNoop());
uassertStatusOK(canonicalQuery.getStatus());
// If the $explain flag was set, we must run the operation on the shards as an explain
// command rather than a find command.
if (canonicalQuery.getValue()->getParsed().isExplain()) {
const LiteParsedQuery& lpq = canonicalQuery.getValue()->getParsed();
BSONObj findCommand = lpq.asFindCommand();
// We default to allPlansExecution verbosity.
auto verbosity = ExplainCommon::EXEC_ALL_PLANS;
const bool secondaryOk = (readPreference.pref != ReadPreference::PrimaryOnly);
rpc::ServerSelectionMetadata metadata(secondaryOk, readPreference);
BSONObjBuilder explainBuilder;
uassertStatusOK(ClusterFind::runExplain(
txn, findCommand, lpq, verbosity, metadata, &explainBuilder));
BSONObj explainObj = explainBuilder.done();
replyToQuery(0, // query result flags
request.p(),
request.m(),
static_cast<const void*>(explainObj.objdata()),
explainObj.objsize(),
1, // numResults
0, // startingFrom
CursorId(0));
return;
}
// Do the work to generate the first batch of results. This blocks waiting to get responses
// from the shard(s).
std::vector<BSONObj> batch;
// 0 means the cursor is exhausted and
// otherwise we assume that a cursor with the returned id can be retrieved via the
// ClusterCursorManager
auto cursorId =
ClusterFind::runQuery(txn, *canonicalQuery.getValue(), readPreference, &batch);
uassertStatusOK(cursorId.getStatus());
// TODO: this constant should be shared between mongos and mongod, and should
// not be inside ShardedClientCursor.
BufBuilder buffer(ShardedClientCursor::INIT_REPLY_BUFFER_SIZE);
// Fill out the response buffer.
int numResults = 0;
for (const auto& obj : batch) {
buffer.appendBuf((void*)obj.objdata(), obj.objsize());
numResults++;
}
replyToQuery(0, // query result flags
request.p(),
request.m(),
buffer.buf(),
buffer.len(),
numResults,
0, // startingFrom
cursorId.getValue());
return;
}
QuerySpec qSpec((string)q.ns, q.query, q.fields, q.ntoskip, q.ntoreturn, q.queryOptions);
// Parse "$maxTimeMS".
StatusWith<int> maxTimeMS = LiteParsedQuery::parseMaxTimeMSQuery(q.query);
uassert(17233, maxTimeMS.getStatus().reason(), maxTimeMS.isOK());
if (_isSystemIndexes(q.ns) && doShardedIndexQuery(txn, request, qSpec)) {
return;
}
ParallelSortClusteredCursor* cursor = new ParallelSortClusteredCursor(qSpec, CommandInfo());
verify(cursor);
// TODO: Move out to Request itself, not strategy based
try {
cursor->init(txn);
if (qSpec.isExplain()) {
BSONObjBuilder explain_builder;
cursor->explain(explain_builder);
explain_builder.appendNumber("executionTimeMillis",
static_cast<long long>(queryTimer.millis()));
BSONObj b = explain_builder.obj();
replyToQuery(0, request.p(), request.m(), b);
delete (cursor);
return;
}
} catch (...) {
delete cursor;
throw;
}
// TODO: Revisit all of this when we revisit the sharded cursor cache
if (cursor->getNumQueryShards() != 1) {
// More than one shard (or zero), manage with a ShardedClientCursor
// NOTE: We may also have *zero* shards here when the returnPartial flag is set.
// Currently the code in ShardedClientCursor handles this.
ShardedClientCursorPtr cc(new ShardedClientCursor(q, cursor));
BufBuilder buffer(ShardedClientCursor::INIT_REPLY_BUFFER_SIZE);
int docCount = 0;
const int startFrom = cc->getTotalSent();
bool hasMore = cc->sendNextBatch(q.ntoreturn, buffer, docCount);
if (hasMore) {
LOG(5) << "storing cursor : " << cc->getId();
int cursorLeftoverMillis = maxTimeMS.getValue() - queryTimer.millis();
if (maxTimeMS.getValue() == 0) { // 0 represents "no limit".
cursorLeftoverMillis = kMaxTimeCursorNoTimeLimit;
} else if (cursorLeftoverMillis <= 0) {
cursorLeftoverMillis = kMaxTimeCursorTimeLimitExpired;
}
cursorCache.store(cc, cursorLeftoverMillis);
}
replyToQuery(0,
request.p(),
request.m(),
buffer.buf(),
buffer.len(),
docCount,
startFrom,
hasMore ? cc->getId() : 0);
} else {
// Only one shard is used
// Remote cursors are stored remotely, we shouldn't need this around.
unique_ptr<ParallelSortClusteredCursor> cursorDeleter(cursor);
ShardPtr shard = grid.shardRegistry()->getShard(txn, cursor->getQueryShardId());
verify(shard.get());
DBClientCursorPtr shardCursor = cursor->getShardCursor(shard->getId());
// Implicitly stores the cursor in the cache
request.reply(*(shardCursor->getMessage()), shardCursor->originalHost());
// We don't want to kill the cursor remotely if there's still data left
shardCursor->decouple();
}
}
void Strategy::queryOp( Request& r ) {
verify( !NamespaceString( r.getns() ).isCommand() );
Timer queryTimer;
QueryMessage q( r.d() );
NamespaceString ns(q.ns);
ClientBasic* client = ClientBasic::getCurrent();
AuthorizationSession* authSession = client->getAuthorizationSession();
Status status = authSession->checkAuthForQuery(ns, q.query);
audit::logQueryAuthzCheck(client, ns, q.query, status.code());
uassertStatusOK(status);
LOG(3) << "query: " << q.ns << " " << q.query << " ntoreturn: " << q.ntoreturn
<< " options: " << q.queryOptions << endl;
if ( q.ntoreturn == 1 && strstr(q.ns, ".$cmd") )
throw UserException( 8010 , "something is wrong, shouldn't see a command here" );
if (q.queryOptions & QueryOption_Exhaust) {
uasserted(18526,
string("the 'exhaust' query option is invalid for mongos queries: ") + q.ns
+ " " + q.query.toString());
}
QuerySpec qSpec( (string)q.ns, q.query, q.fields, q.ntoskip, q.ntoreturn, q.queryOptions );
// Parse "$maxTimeMS".
StatusWith<int> maxTimeMS = LiteParsedQuery::parseMaxTimeMSQuery( q.query );
uassert( 17233,
maxTimeMS.getStatus().reason(),
maxTimeMS.isOK() );
if ( _isSystemIndexes( q.ns ) && doShardedIndexQuery( r, qSpec )) {
return;
}
ParallelSortClusteredCursor * cursor = new ParallelSortClusteredCursor( qSpec, CommandInfo() );
verify( cursor );
// TODO: Move out to Request itself, not strategy based
try {
cursor->init();
if ( qSpec.isExplain() ) {
BSONObjBuilder explain_builder;
cursor->explain( explain_builder );
explain_builder.appendNumber( "millis",
static_cast<long long>(queryTimer.millis()) );
BSONObj b = explain_builder.obj();
replyToQuery( 0 , r.p() , r.m() , b );
delete( cursor );
return;
}
}
catch(...) {
delete cursor;
throw;
}
// TODO: Revisit all of this when we revisit the sharded cursor cache
if (cursor->getNumQueryShards() != 1) {
// More than one shard (or zero), manage with a ShardedClientCursor
// NOTE: We may also have *zero* shards here when the returnPartial flag is set.
// Currently the code in ShardedClientCursor handles this.
ShardedClientCursorPtr cc (new ShardedClientCursor( q , cursor ));
BufBuilder buffer( ShardedClientCursor::INIT_REPLY_BUFFER_SIZE );
int docCount = 0;
const int startFrom = cc->getTotalSent();
bool hasMore = cc->sendNextBatch( r, q.ntoreturn, buffer, docCount );
if ( hasMore ) {
LOG(5) << "storing cursor : " << cc->getId() << endl;
int cursorLeftoverMillis = maxTimeMS.getValue() - queryTimer.millis();
if ( maxTimeMS.getValue() == 0 ) { // 0 represents "no limit".
cursorLeftoverMillis = kMaxTimeCursorNoTimeLimit;
}
else if ( cursorLeftoverMillis <= 0 ) {
cursorLeftoverMillis = kMaxTimeCursorTimeLimitExpired;
}
cursorCache.store( cc, cursorLeftoverMillis );
}
replyToQuery( 0, r.p(), r.m(), buffer.buf(), buffer.len(), docCount,
startFrom, hasMore ? cc->getId() : 0 );
}
else{
// Only one shard is used
// Remote cursors are stored remotely, we shouldn't need this around.
scoped_ptr<ParallelSortClusteredCursor> cursorDeleter( cursor );
ShardPtr shard = cursor->getQueryShard();
verify( shard.get() );
DBClientCursorPtr shardCursor = cursor->getShardCursor(*shard);
// Implicitly stores the cursor in the cache
r.reply( *(shardCursor->getMessage()) , shardCursor->originalHost() );
// We don't want to kill the cursor remotely if there's still data left
shardCursor->decouple();
}
}
