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-rw-r--r--src/mongo/db/commands/find_cmd.cpp541
1 files changed, 270 insertions, 271 deletions
diff --git a/src/mongo/db/commands/find_cmd.cpp b/src/mongo/db/commands/find_cmd.cpp
index 0bc9589bbef..d40ff0f766e 100644
--- a/src/mongo/db/commands/find_cmd.cpp
+++ b/src/mongo/db/commands/find_cmd.cpp
@@ -55,313 +55,312 @@
namespace mongo {
- /**
- * A command for running .find() queries.
- */
- class FindCmd : public Command {
- MONGO_DISALLOW_COPYING(FindCmd);
- public:
- FindCmd() : Command("find") { }
+/**
+ * A command for running .find() queries.
+ */
+class FindCmd : public Command {
+ MONGO_DISALLOW_COPYING(FindCmd);
- bool isWriteCommandForConfigServer() const override { return false; }
+public:
+ FindCmd() : Command("find") {}
- bool slaveOk() const override { return false; }
+ bool isWriteCommandForConfigServer() const override {
+ return false;
+ }
- bool slaveOverrideOk() const override { return true; }
+ bool slaveOk() const override {
+ return false;
+ }
- bool maintenanceOk() const override { return false; }
+ bool slaveOverrideOk() const override {
+ return true;
+ }
- bool adminOnly() const override { return false; }
+ bool maintenanceOk() const override {
+ return false;
+ }
- void help(std::stringstream& help) const override {
- help << "query for documents";
- }
+ bool adminOnly() const override {
+ return false;
+ }
- /**
- * A find command does not increment the command counter, but rather increments the
- * query counter.
- */
- bool shouldAffectCommandCounter() const override { return false; }
+ void help(std::stringstream& help) const override {
+ help << "query for documents";
+ }
- Status checkAuthForCommand(ClientBasic* client,
- const std::string& dbname,
- const BSONObj& cmdObj) override {
- AuthorizationSession* authzSession = AuthorizationSession::get(client);
- ResourcePattern pattern = parseResourcePattern(dbname, cmdObj);
+ /**
+ * A find command does not increment the command counter, but rather increments the
+ * query counter.
+ */
+ bool shouldAffectCommandCounter() const override {
+ return false;
+ }
- if (authzSession->isAuthorizedForActionsOnResource(pattern, ActionType::find)) {
- return Status::OK();
- }
+ Status checkAuthForCommand(ClientBasic* client,
+ const std::string& dbname,
+ const BSONObj& cmdObj) override {
+ AuthorizationSession* authzSession = AuthorizationSession::get(client);
+ ResourcePattern pattern = parseResourcePattern(dbname, cmdObj);
- return Status(ErrorCodes::Unauthorized, "unauthorized");
+ if (authzSession->isAuthorizedForActionsOnResource(pattern, ActionType::find)) {
+ return Status::OK();
}
- Status explain(OperationContext* txn,
- const std::string& dbname,
- const BSONObj& cmdObj,
- ExplainCommon::Verbosity verbosity,
- BSONObjBuilder* out) const override {
- const std::string fullns = parseNs(dbname, cmdObj);
- const NamespaceString nss(fullns);
- if (!nss.isValid()) {
- return {ErrorCodes::InvalidNamespace,
- str::stream() << "Invalid collection name: " << nss.ns()};
- }
+ return Status(ErrorCodes::Unauthorized, "unauthorized");
+ }
+
+ Status explain(OperationContext* txn,
+ const std::string& dbname,
+ const BSONObj& cmdObj,
+ ExplainCommon::Verbosity verbosity,
+ BSONObjBuilder* out) const override {
+ const std::string fullns = parseNs(dbname, cmdObj);
+ const NamespaceString nss(fullns);
+ if (!nss.isValid()) {
+ return {ErrorCodes::InvalidNamespace,
+ str::stream() << "Invalid collection name: " << nss.ns()};
+ }
- // Parse the command BSON to a LiteParsedQuery.
- const bool isExplain = true;
- auto lpqStatus = LiteParsedQuery::makeFromFindCommand(nss, cmdObj, isExplain);
- if (!lpqStatus.isOK()) {
- return lpqStatus.getStatus();
- }
+ // Parse the command BSON to a LiteParsedQuery.
+ const bool isExplain = true;
+ auto lpqStatus = LiteParsedQuery::makeFromFindCommand(nss, cmdObj, isExplain);
+ if (!lpqStatus.isOK()) {
+ return lpqStatus.getStatus();
+ }
- // Finish the parsing step by using the LiteParsedQuery to create a CanonicalQuery.
- std::unique_ptr<CanonicalQuery> cq;
- {
- CanonicalQuery* rawCq;
- WhereCallbackReal whereCallback(txn, nss.db());
- Status canonStatus = CanonicalQuery::canonicalize(lpqStatus.getValue().release(),
- &rawCq,
- whereCallback);
- if (!canonStatus.isOK()) {
- return canonStatus;
- }
- cq.reset(rawCq);
+ // Finish the parsing step by using the LiteParsedQuery to create a CanonicalQuery.
+ std::unique_ptr<CanonicalQuery> cq;
+ {
+ CanonicalQuery* rawCq;
+ WhereCallbackReal whereCallback(txn, nss.db());
+ Status canonStatus =
+ CanonicalQuery::canonicalize(lpqStatus.getValue().release(), &rawCq, whereCallback);
+ if (!canonStatus.isOK()) {
+ return canonStatus;
}
+ cq.reset(rawCq);
+ }
- AutoGetCollectionForRead ctx(txn, nss);
- // The collection may be NULL. If so, getExecutor() should handle it by returning
- // an execution tree with an EOFStage.
- Collection* collection = ctx.getCollection();
-
- // We have a parsed query. Time to get the execution plan for it.
- std::unique_ptr<PlanExecutor> exec;
- {
- PlanExecutor* rawExec;
- Status execStatus = getExecutorFind(txn,
- collection,
- nss,
- cq.release(),
- PlanExecutor::YIELD_AUTO,
- &rawExec);
- if (!execStatus.isOK()) {
- return execStatus;
- }
- exec.reset(rawExec);
+ AutoGetCollectionForRead ctx(txn, nss);
+ // The collection may be NULL. If so, getExecutor() should handle it by returning
+ // an execution tree with an EOFStage.
+ Collection* collection = ctx.getCollection();
+
+ // We have a parsed query. Time to get the execution plan for it.
+ std::unique_ptr<PlanExecutor> exec;
+ {
+ PlanExecutor* rawExec;
+ Status execStatus = getExecutorFind(
+ txn, collection, nss, cq.release(), PlanExecutor::YIELD_AUTO, &rawExec);
+ if (!execStatus.isOK()) {
+ return execStatus;
}
+ exec.reset(rawExec);
+ }
- // Got the execution tree. Explain it.
- Explain::explainStages(exec.get(), verbosity, out);
- return Status::OK();
+ // Got the execution tree. Explain it.
+ Explain::explainStages(exec.get(), verbosity, out);
+ return Status::OK();
+ }
+
+ /**
+ * Runs a query using the following steps:
+ * 1) Parsing.
+ * 2) Acquire locks.
+ * 3) Plan query, obtaining an executor that can run it.
+ * 4) Setup a cursor for the query, which may be used on subsequent getMores.
+ * 5) Generate the first batch.
+ * 6) Save state for getMore.
+ * 7) Generate response to send to the client.
+ *
+ * TODO: Rather than using the sharding version available in thread-local storage
+ * (i.e. call to shardingState.needCollectionMetadata() below), shard version
+ * information should be passed as part of the command parameter.
+ */
+ bool run(OperationContext* txn,
+ const std::string& dbname,
+ BSONObj& cmdObj,
+ int options,
+ std::string& errmsg,
+ BSONObjBuilder& result) override {
+ const std::string fullns = parseNs(dbname, cmdObj);
+ const NamespaceString nss(fullns);
+ if (!nss.isValid()) {
+ return appendCommandStatus(result,
+ {ErrorCodes::InvalidNamespace,
+ str::stream() << "Invalid collection name: " << nss.ns()});
}
- /**
- * Runs a query using the following steps:
- * 1) Parsing.
- * 2) Acquire locks.
- * 3) Plan query, obtaining an executor that can run it.
- * 4) Setup a cursor for the query, which may be used on subsequent getMores.
- * 5) Generate the first batch.
- * 6) Save state for getMore.
- * 7) Generate response to send to the client.
- *
- * TODO: Rather than using the sharding version available in thread-local storage
- * (i.e. call to shardingState.needCollectionMetadata() below), shard version
- * information should be passed as part of the command parameter.
- */
- bool run(OperationContext* txn,
- const std::string& dbname,
- BSONObj& cmdObj,
- int options,
- std::string& errmsg,
- BSONObjBuilder& result) override {
- const std::string fullns = parseNs(dbname, cmdObj);
- const NamespaceString nss(fullns);
- if (!nss.isValid()) {
- return appendCommandStatus(result, {ErrorCodes::InvalidNamespace,
- str::stream() << "Invalid collection name: "
- << nss.ns()});
- }
+ // Although it is a command, a find command gets counted as a query.
+ globalOpCounters.gotQuery();
- // Although it is a command, a find command gets counted as a query.
- globalOpCounters.gotQuery();
+ if (txn->getClient()->isInDirectClient()) {
+ return appendCommandStatus(
+ result,
+ Status(ErrorCodes::IllegalOperation, "Cannot run find command from eval()"));
+ }
- if (txn->getClient()->isInDirectClient()) {
- return appendCommandStatus(result,
- Status(ErrorCodes::IllegalOperation,
- "Cannot run find command from eval()"));
- }
+ // 1a) Parse the command BSON to a LiteParsedQuery.
+ const bool isExplain = false;
+ auto lpqStatus = LiteParsedQuery::makeFromFindCommand(nss, cmdObj, isExplain);
+ if (!lpqStatus.isOK()) {
+ return appendCommandStatus(result, lpqStatus.getStatus());
+ }
- // 1a) Parse the command BSON to a LiteParsedQuery.
- const bool isExplain = false;
- auto lpqStatus = LiteParsedQuery::makeFromFindCommand(nss, cmdObj, isExplain);
- if (!lpqStatus.isOK()) {
- return appendCommandStatus(result, lpqStatus.getStatus());
- }
+ auto& lpq = lpqStatus.getValue();
- auto& lpq = lpqStatus.getValue();
-
- // Fill out curop information.
- int ntoreturn = lpq->getBatchSize().value_or(0);
- beginQueryOp(txn, nss, cmdObj, ntoreturn, lpq->getSkip());
-
- // 1b) Finish the parsing step by using the LiteParsedQuery to create a CanonicalQuery.
- std::unique_ptr<CanonicalQuery> cq;
- {
- CanonicalQuery* rawCq;
- WhereCallbackReal whereCallback(txn, nss.db());
- Status canonStatus = CanonicalQuery::canonicalize(lpq.release(),
- &rawCq,
- whereCallback);
- if (!canonStatus.isOK()) {
- return appendCommandStatus(result, canonStatus);
- }
- cq.reset(rawCq);
- }
+ // Fill out curop information.
+ int ntoreturn = lpq->getBatchSize().value_or(0);
+ beginQueryOp(txn, nss, cmdObj, ntoreturn, lpq->getSkip());
- // 2) Acquire locks.
- AutoGetCollectionForRead ctx(txn, nss);
- Collection* collection = ctx.getCollection();
-
- const int dbProfilingLevel = ctx.getDb() ? ctx.getDb()->getProfilingLevel() :
- serverGlobalParams.defaultProfile;
-
- // It is possible that the sharding version will change during yield while we are
- // retrieving a plan executor. If this happens we will throw an error and mongos will
- // retry.
- const ChunkVersion shardingVersionAtStart = shardingState.getVersion(nss.ns());
-
- // 3) Get the execution plan for the query.
- std::unique_ptr<PlanExecutor> execHolder;
- {
- PlanExecutor* rawExec;
- Status execStatus = getExecutorFind(txn,
- collection,
- nss,
- cq.release(),
- PlanExecutor::YIELD_AUTO,
- &rawExec);
- if (!execStatus.isOK()) {
- return appendCommandStatus(result, execStatus);
- }
- execHolder.reset(rawExec);
+ // 1b) Finish the parsing step by using the LiteParsedQuery to create a CanonicalQuery.
+ std::unique_ptr<CanonicalQuery> cq;
+ {
+ CanonicalQuery* rawCq;
+ WhereCallbackReal whereCallback(txn, nss.db());
+ Status canonStatus = CanonicalQuery::canonicalize(lpq.release(), &rawCq, whereCallback);
+ if (!canonStatus.isOK()) {
+ return appendCommandStatus(result, canonStatus);
}
+ cq.reset(rawCq);
+ }
- // TODO: Currently, chunk ranges are kept around until all ClientCursors created while
- // the chunk belonged on this node are gone. Separating chunk lifetime management from
- // ClientCursor should allow this check to go away.
- if (!shardingState.getVersion(nss.ns()).isWriteCompatibleWith(shardingVersionAtStart)) {
- // Version changed while retrieving a PlanExecutor. Terminate the operation,
- // signaling that mongos should retry.
- throw SendStaleConfigException(nss.ns(),
- "version changed during find command",
- shardingVersionAtStart,
- shardingState.getVersion(nss.ns()));
+ // 2) Acquire locks.
+ AutoGetCollectionForRead ctx(txn, nss);
+ Collection* collection = ctx.getCollection();
+
+ const int dbProfilingLevel =
+ ctx.getDb() ? ctx.getDb()->getProfilingLevel() : serverGlobalParams.defaultProfile;
+
+ // It is possible that the sharding version will change during yield while we are
+ // retrieving a plan executor. If this happens we will throw an error and mongos will
+ // retry.
+ const ChunkVersion shardingVersionAtStart = shardingState.getVersion(nss.ns());
+
+ // 3) Get the execution plan for the query.
+ std::unique_ptr<PlanExecutor> execHolder;
+ {
+ PlanExecutor* rawExec;
+ Status execStatus = getExecutorFind(
+ txn, collection, nss, cq.release(), PlanExecutor::YIELD_AUTO, &rawExec);
+ if (!execStatus.isOK()) {
+ return appendCommandStatus(result, execStatus);
}
+ execHolder.reset(rawExec);
+ }
- if (!collection) {
- // No collection. Just fill out curop indicating that there were zero results and
- // there is no ClientCursor id, and then return.
- const int numResults = 0;
- const CursorId cursorId = 0;
- endQueryOp(txn, execHolder.get(), dbProfilingLevel, numResults, cursorId);
- appendCursorResponseObject(cursorId, nss.ns(), BSONArray(), &result);
- return true;
- }
+ // TODO: Currently, chunk ranges are kept around until all ClientCursors created while
+ // the chunk belonged on this node are gone. Separating chunk lifetime management from
+ // ClientCursor should allow this check to go away.
+ if (!shardingState.getVersion(nss.ns()).isWriteCompatibleWith(shardingVersionAtStart)) {
+ // Version changed while retrieving a PlanExecutor. Terminate the operation,
+ // signaling that mongos should retry.
+ throw SendStaleConfigException(nss.ns(),
+ "version changed during find command",
+ shardingVersionAtStart,
+ shardingState.getVersion(nss.ns()));
+ }
- const LiteParsedQuery& pq = execHolder->getCanonicalQuery()->getParsed();
-
- // 4) If possible, register the execution plan inside a ClientCursor, and pin that
- // cursor. In this case, ownership of the PlanExecutor is transferred to the
- // ClientCursor, and 'exec' becomes null.
- //
- // First unregister the PlanExecutor so it can be re-registered with ClientCursor.
- execHolder->deregisterExec();
-
- // Create a ClientCursor containing this plan executor. We don't have to worry
- // about leaking it as it's inserted into a global map by its ctor.
- ClientCursor* cursor = new ClientCursor(collection->getCursorManager(),
- execHolder.release(),
- nss.ns(),
- pq.getOptions(),
- pq.getFilter());
- CursorId cursorId = cursor->cursorid();
- ClientCursorPin ccPin(collection->getCursorManager(), cursorId);
-
- // On early return, get rid of the the cursor.
- ScopeGuard cursorFreer = MakeGuard(&ClientCursorPin::deleteUnderlying, ccPin);
-
- invariant(!execHolder);
- PlanExecutor* exec = cursor->getExecutor();
-
- // 5) Stream query results, adding them to a BSONArray as we go.
- BSONArrayBuilder firstBatch;
- BSONObj obj;
- PlanExecutor::ExecState state;
- int numResults = 0;
- while (!enoughForFirstBatch(pq, numResults, firstBatch.len())
- && PlanExecutor::ADVANCED == (state = exec->getNext(&obj, NULL))) {
- // If adding this object will cause us to exceed the BSON size limit, then we stash
- // it for later.
- if (firstBatch.len() + obj.objsize() > BSONObjMaxUserSize && numResults > 0) {
- exec->enqueue(obj);
- break;
- }
-
- // Add result to output buffer.
- firstBatch.append(obj);
- numResults++;
- }
+ if (!collection) {
+ // No collection. Just fill out curop indicating that there were zero results and
+ // there is no ClientCursor id, and then return.
+ const int numResults = 0;
+ const CursorId cursorId = 0;
+ endQueryOp(txn, execHolder.get(), dbProfilingLevel, numResults, cursorId);
+ appendCursorResponseObject(cursorId, nss.ns(), BSONArray(), &result);
+ return true;
+ }
- // Throw an assertion if query execution fails for any reason.
- if (PlanExecutor::FAILURE == state || PlanExecutor::DEAD == state) {
- const std::unique_ptr<PlanStageStats> stats(exec->getStats());
- error() << "Plan executor error during find command: "
- << PlanExecutor::statestr(state)
- << ", stats: " << Explain::statsToBSON(*stats);
-
- return appendCommandStatus(result,
- Status(ErrorCodes::OperationFailed,
- str::stream()
- << "Executor error during find command: "
- << WorkingSetCommon::toStatusString(obj)));
+ const LiteParsedQuery& pq = execHolder->getCanonicalQuery()->getParsed();
+
+ // 4) If possible, register the execution plan inside a ClientCursor, and pin that
+ // cursor. In this case, ownership of the PlanExecutor is transferred to the
+ // ClientCursor, and 'exec' becomes null.
+ //
+ // First unregister the PlanExecutor so it can be re-registered with ClientCursor.
+ execHolder->deregisterExec();
+
+ // Create a ClientCursor containing this plan executor. We don't have to worry
+ // about leaking it as it's inserted into a global map by its ctor.
+ ClientCursor* cursor = new ClientCursor(collection->getCursorManager(),
+ execHolder.release(),
+ nss.ns(),
+ pq.getOptions(),
+ pq.getFilter());
+ CursorId cursorId = cursor->cursorid();
+ ClientCursorPin ccPin(collection->getCursorManager(), cursorId);
+
+ // On early return, get rid of the the cursor.
+ ScopeGuard cursorFreer = MakeGuard(&ClientCursorPin::deleteUnderlying, ccPin);
+
+ invariant(!execHolder);
+ PlanExecutor* exec = cursor->getExecutor();
+
+ // 5) Stream query results, adding them to a BSONArray as we go.
+ BSONArrayBuilder firstBatch;
+ BSONObj obj;
+ PlanExecutor::ExecState state;
+ int numResults = 0;
+ while (!enoughForFirstBatch(pq, numResults, firstBatch.len()) &&
+ PlanExecutor::ADVANCED == (state = exec->getNext(&obj, NULL))) {
+ // If adding this object will cause us to exceed the BSON size limit, then we stash
+ // it for later.
+ if (firstBatch.len() + obj.objsize() > BSONObjMaxUserSize && numResults > 0) {
+ exec->enqueue(obj);
+ break;
}
- // 6) Set up the cursor for getMore.
- if (shouldSaveCursor(txn, collection, state, exec)) {
- // State will be restored on getMore.
- exec->saveState();
-
- cursor->setLeftoverMaxTimeMicros(CurOp::get(txn)->getRemainingMaxTimeMicros());
- cursor->setPos(numResults);
-
- // Don't stash the RU for tailable cursors at EOF, let them get a new RU on their
- // next getMore.
- if (!(pq.isTailable() && state == PlanExecutor::IS_EOF)) {
- // We stash away the RecoveryUnit in the ClientCursor. It's used for
- // subsequent getMore requests. The calling OpCtx gets a fresh RecoveryUnit.
- txn->recoveryUnit()->abandonSnapshot();
- cursor->setOwnedRecoveryUnit(txn->releaseRecoveryUnit());
- StorageEngine* engine = getGlobalServiceContext()->getGlobalStorageEngine();
- txn->setRecoveryUnit(engine->newRecoveryUnit(),
- OperationContext::kNotInUnitOfWork);
- }
- }
- else {
- cursorId = 0;
- }
+ // Add result to output buffer.
+ firstBatch.append(obj);
+ numResults++;
+ }
- // Fill out curop based on the results.
- endQueryOp(txn, exec, dbProfilingLevel, numResults, cursorId);
+ // Throw an assertion if query execution fails for any reason.
+ if (PlanExecutor::FAILURE == state || PlanExecutor::DEAD == state) {
+ const std::unique_ptr<PlanStageStats> stats(exec->getStats());
+ error() << "Plan executor error during find command: " << PlanExecutor::statestr(state)
+ << ", stats: " << Explain::statsToBSON(*stats);
+
+ return appendCommandStatus(result,
+ Status(ErrorCodes::OperationFailed,
+ str::stream()
+ << "Executor error during find command: "
+ << WorkingSetCommon::toStatusString(obj)));
+ }
- // 7) Generate the response object to send to the client.
- appendCursorResponseObject(cursorId, nss.ns(), firstBatch.arr(), &result);
- if (cursorId) {
- cursorFreer.Dismiss();
+ // 6) Set up the cursor for getMore.
+ if (shouldSaveCursor(txn, collection, state, exec)) {
+ // State will be restored on getMore.
+ exec->saveState();
+
+ cursor->setLeftoverMaxTimeMicros(CurOp::get(txn)->getRemainingMaxTimeMicros());
+ cursor->setPos(numResults);
+
+ // Don't stash the RU for tailable cursors at EOF, let them get a new RU on their
+ // next getMore.
+ if (!(pq.isTailable() && state == PlanExecutor::IS_EOF)) {
+ // We stash away the RecoveryUnit in the ClientCursor. It's used for
+ // subsequent getMore requests. The calling OpCtx gets a fresh RecoveryUnit.
+ txn->recoveryUnit()->abandonSnapshot();
+ cursor->setOwnedRecoveryUnit(txn->releaseRecoveryUnit());
+ StorageEngine* engine = getGlobalServiceContext()->getGlobalStorageEngine();
+ txn->setRecoveryUnit(engine->newRecoveryUnit(), OperationContext::kNotInUnitOfWork);
}
- return true;
+ } else {
+ cursorId = 0;
+ }
+
+ // Fill out curop based on the results.
+ endQueryOp(txn, exec, dbProfilingLevel, numResults, cursorId);
+
+ // 7) Generate the response object to send to the client.
+ appendCursorResponseObject(cursorId, nss.ns(), firstBatch.arr(), &result);
+ if (cursorId) {
+ cursorFreer.Dismiss();
}
+ return true;
+ }
- } findCmd;
+} findCmd;
-} // namespace mongo
+} // namespace mongo
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