void replyToQuery(int queryResultFlags,
AbstractMessagingPort* p,
Message& requestMsg,
const void* data,
int size,
int nReturned,
int startingFrom,
long long cursorId) {
OpQueryReplyBuilder reply;
reply.bufBuilderForResults().appendBuf(data, size);
reply.send(p, queryResultFlags, requestMsg, nReturned, startingFrom, cursorId);
}
void replyToQuery(int queryResultFlags,
const transport::SessionHandle& session,
Message& requestMsg,
const void* data,
int size,
int nReturned,
int startingFrom,
long long cursorId) {
OpQueryReplyBuilder reply;
reply.bufBuilderForResults().appendBuf(data, size);
reply.send(session, queryResultFlags, requestMsg, nReturned, startingFrom, cursorId);
}
void Strategy::queryOp(OperationContext* txn, Request& request) {
verify(!NamespaceString(request.getns()).isCommand());
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());
}
// 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, ExtensionsCallbackNoop());
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(
Strategy::explainFind(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. 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());
// Fill out the response buffer.
int numResults = 0;
OpQueryReplyBuilder reply;
for (auto&& obj : batch) {
obj.appendSelfToBufBuilder(reply.bufBuilderForResults());
numResults++;
}
reply.send(request.p(),
0, // query result flags
request.m(),
numResults,
0, // startingFrom
cursorId.getValue());
}