SERVER-16101 replace DeleteExecutor with ParsedDelete

5 files changed, 231 insertions, 334 deletions

diff --git a/src/mongo/db/ops/delete.cpp b/src/mongo/db/ops/delete.cpp
index 8fc12448a21..fcaa2b6d02b 100644
--- a/src/mongo/db/ops/delete.cpp
+++ b/src/mongo/db/ops/delete.cpp
@@ -28,8 +28,10 @@
 
 #include "mongo/db/ops/delete.h"
 
-#include "mongo/db/ops/delete_executor.h"
+#include "mongo/db/exec/delete.h"
 #include "mongo/db/ops/delete_request.h"
+#include "mongo/db/ops/parsed_delete.h"
+#include "mongo/db/query/get_executor.h"
 
 namespace mongo {
 
@@ -55,8 +57,21 @@ namespace mongo {
         request.setGod(god);
         request.setFromMigrate(fromMigrate);
         request.setYieldPolicy(policy);
-        DeleteExecutor executor(txn, &request);
-        return executor.execute(db);
+
+        Collection* collection = NULL;
+        if (db) {
+            collection = db->getCollection(txn, nsString.ns());
+        }
+
+        ParsedDelete parsedDelete(txn, &request);
+        uassertStatusOK(parsedDelete.parseRequest());
+
+        PlanExecutor* rawExec;
+        uassertStatusOK(getExecutorDelete(txn, collection, &parsedDelete, &rawExec));
+        boost::scoped_ptr<PlanExecutor> exec(rawExec);
+
+        uassertStatusOK(exec->executePlan());
+        return DeleteStage::getNumDeleted(exec.get());
     }
 
 }  // namespace mongo
diff --git a/src/mongo/db/ops/delete_executor.cpp b/src/mongo/db/ops/delete_executor.cpp
deleted file mode 100644
index 01b08e6c56d..00000000000
--- a/src/mongo/db/ops/delete_executor.cpp
+++ /dev/null
@@ -1,199 +0,0 @@
-/**
- *    Copyright (C) 2014 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kWrite
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/db/ops/delete_executor.h"
-
-#include "mongo/db/catalog/collection.h"
-#include "mongo/db/catalog/database.h"
-#include "mongo/db/exec/delete.h"
-#include "mongo/db/ops/delete_request.h"
-#include "mongo/db/query/canonical_query.h"
-#include "mongo/db/query/get_executor.h"
-#include "mongo/db/query/query_planner_common.h"
-#include "mongo/db/repl/repl_coordinator_global.h"
-#include "mongo/util/assert_util.h"
-#include "mongo/util/log.h"
-#include "mongo/util/mongoutils/str.h"
-
-namespace mongo {
-
-    DeleteExecutor::DeleteExecutor(OperationContext* txn, const DeleteRequest* request) :
-        _txn(txn),
-        _request(request),
-        _canonicalQuery(),
-        _isQueryParsed(false) {
-    }
-
-    DeleteExecutor::~DeleteExecutor() {}
-
-    Status DeleteExecutor::prepare() {
-        if (_isQueryParsed)
-            return Status::OK();
-
-        dassert(!_canonicalQuery.get());
-
-        if (CanonicalQuery::isSimpleIdQuery(_request->getQuery())) {
-            _isQueryParsed = true;
-            return Status::OK();
-        }
-
-        CanonicalQuery* cqRaw;
-        const WhereCallbackReal whereCallback(_txn, _request->getNamespaceString().db());
-
-        Status status = CanonicalQuery::canonicalize(_request->getNamespaceString().ns(),
-                                                     _request->getQuery(),
-                                                     _request->isExplain(),
-                                                     &cqRaw,
-                                                     whereCallback);
-        if (status.isOK()) {
-            _canonicalQuery.reset(cqRaw);
-            _isQueryParsed = true;
-        }
-
-        return status;
-    }
-
-    PlanExecutor* DeleteExecutor::getPlanExecutor() {
-        return _exec.get();
-    }
-
-    Status DeleteExecutor::prepareInLock(Database* db) {
-        // If we have a non-NULL PlanExecutor, then we've already done the in-lock preparation.
-        if (_exec.get()) {
-            return Status::OK();
-        }
-
-        uassert(17417,
-                mongoutils::str::stream() <<
-                "DeleteExecutor::prepare() failed to parse query " << _request->getQuery(),
-                _isQueryParsed);
-
-        const NamespaceString& ns(_request->getNamespaceString());
-        if (!_request->isGod()) {
-            if (ns.isSystem()) {
-                uassert(12050,
-                        "cannot delete from system namespace",
-                        legalClientSystemNS(ns.ns(), true));
-            }
-            if (ns.ns().find('$') != string::npos) {
-                log() << "cannot delete from collection with reserved $ in name: " << ns << endl;
-                uasserted(10100, "cannot delete from collection with reserved $ in name");
-            }
-        }
-
-        // Note that 'collection' may by NULL in the case that the collection or database we are
-        // trying to delete from does not exist. NULL 'collection' is handled by
-        // getExecutorDelete(); we expect to get back a plan executor whose plan is a DeleteStage
-        // on top of an EOFStage.
-        Collection* collection = NULL;
-        if (db) {
-            collection = db->getCollection(_txn, ns.ns());
-        }
-
-        if (collection && collection->isCapped()) {
-            return Status(ErrorCodes::IllegalOperation,
-                          str::stream() << "cannot remove from a capped collection: " <<  ns.ns());
-        }
-
-        if (_request->shouldCallLogOp() &&
-            !repl::getGlobalReplicationCoordinator()->canAcceptWritesForDatabase(ns.db())) {
-            return Status(ErrorCodes::NotMaster,
-                          str::stream() << "Not primary while removing from " << ns.ns());
-        }
-
-        // If yielding is allowed for this plan, then set an auto yield policy. Otherwise set
-        // a manual yield policy.
-        const bool canYield = !_request->isGod() &&
-            PlanExecutor::YIELD_AUTO == _request->getYieldPolicy() && (
-            _canonicalQuery.get() ?
-            !QueryPlannerCommon::hasNode(_canonicalQuery->root(), MatchExpression::ATOMIC) :
-            !LiteParsedQuery::isQueryIsolated(_request->getQuery()));
-
-        PlanExecutor::YieldPolicy policy = canYield ? PlanExecutor::YIELD_AUTO :
-                                                      PlanExecutor::YIELD_MANUAL;
-
-        PlanExecutor* rawExec;
-        Status getExecStatus = Status::OK();
-        if (_canonicalQuery.get()) {
-            // This is the non-idhack branch.
-            getExecStatus = getExecutorDelete(_txn,
-                                              collection,
-                                              _canonicalQuery.release(),
-                                              _request->isMulti(),
-                                              _request->shouldCallLogOp(),
-                                              _request->isFromMigrate(),
-                                              _request->isExplain(),
-                                              policy,
-                                              &rawExec);
-        }
-        else {
-            // This is the idhack branch.
-            getExecStatus = getExecutorDelete(_txn,
-                                              collection,
-                                              ns.ns(),
-                                              _request->getQuery(),
-                                              _request->isMulti(),
-                                              _request->shouldCallLogOp(),
-                                              _request->isFromMigrate(),
-                                              _request->isExplain(),
-                                              policy,
-                                              &rawExec);
-        }
-
-        if (!getExecStatus.isOK()) {
-            return getExecStatus;
-        }
-
-        invariant(rawExec);
-        _exec.reset(rawExec);
-
-        return Status::OK();
-    }
-
-    long long DeleteExecutor::execute(Database* db) {
-        uassertStatusOK(prepare());
-
-        // If we've already done the in-lock preparation, this is a no-op.
-        uassertStatusOK(prepareInLock(db));
-        invariant(_exec.get());
-
-        uassertStatusOK(_exec->executePlan());
-
-        // Extract the number of documents deleted from the DeleteStage stats.
-        invariant(_exec->getRootStage()->stageType() == STAGE_DELETE);
-        DeleteStage* deleteStage = static_cast<DeleteStage*>(_exec->getRootStage());
-        const DeleteStats* deleteStats =
-            static_cast<const DeleteStats*>(deleteStage->getSpecificStats());
-        return deleteStats->docsDeleted;
-    }
-
-}  // namespace mongo
diff --git a/src/mongo/db/ops/delete_executor.h b/src/mongo/db/ops/delete_executor.h
deleted file mode 100644
index cc984af1c95..00000000000
--- a/src/mongo/db/ops/delete_executor.h
+++ /dev/null
@@ -1,132 +0,0 @@
-/**
- *    Copyright (C) 2014 MongoDB Inc.
- *
- *    This program is free software: you can redistribute it and/or  modify
- *    it under the terms of the GNU Affero General Public License, version 3,
- *    as published by the Free Software Foundation.
- *
- *    This program is distributed in the hope that it will be useful,
- *    but WITHOUT ANY WARRANTY; without even the implied warranty of
- *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *    GNU Affero General Public License for more details.
- *
- *    You should have received a copy of the GNU Affero General Public License
- *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
- *
- *    As a special exception, the copyright holders give permission to link the
- *    code of portions of this program with the OpenSSL library under certain
- *    conditions as described in each individual source file and distribute
- *    linked combinations including the program with the OpenSSL library. You
- *    must comply with the GNU Affero General Public License in all respects for
- *    all of the code used other than as permitted herein. If you modify file(s)
- *    with this exception, you may extend this exception to your version of the
- *    file(s), but you are not obligated to do so. If you do not wish to do so,
- *    delete this exception statement from your version. If you delete this
- *    exception statement from all source files in the program, then also delete
- *    it in the license file.
- */
-
-#pragma once
-
-#include <memory>
-
-#include "mongo/base/disallow_copying.h"
-#include "mongo/base/status.h"
-#include "mongo/db/query/plan_executor.h"
-
-
-namespace mongo {
-
-    class CanonicalQuery;
-    class Database;
-    class DeleteRequest;
-    class OperationContext;
-
-    /**
-     * Implementation of the processing of a delete operation in a mongod.
-     *
-     * The executor has two important methods, prepare() and execute().  The prepare() method can
-     * run without locks, and does whatever parsing and precomputation can be done without access to
-     * database data.  The execute method performs the delete, but the caller must already hold the
-     * appropriate database lock.
-     *
-     * Expected usage is approximately:
-     *   DeleteRequest request(...);
-     *   // configure request
-     *   DeleteExecutor executor(txn, &request);
-     *   uassertStatusOK(executor.prepare());
-     *   // Get locks, get ready to execute.
-     *   try {
-     *       long long nDeleted = executor.execute();
-     *   }
-     *   catch (const DBException& ex) {
-     *       // Error handling.
-     *   }
-     */
-    class DeleteExecutor {
-        MONGO_DISALLOW_COPYING(DeleteExecutor);
-    public:
-        /**
-         * Constructs a delete executor.
-         *
-         * The object pointed to by "request" must stay in scope for the life of the constructed
-         * executor.
-         */
-        DeleteExecutor(OperationContext* txn, const DeleteRequest* request);
-
-        ~DeleteExecutor();
-
-        /**
-         * Performs preparatory work that does not require database locks.
-         *
-         * Returns Status::OK() on success.  Other results indicate that the executor will not run
-         * correctly, and should be abandoned.
-         *
-         * Calling prepare() is optional.  It is available for situations in which the user
-         * wishes to do as much work as possible before acquiring database locks.
-         */
-        Status prepare();
-
-        /**
-         * Performs preparatory work that *does* require the appropriate database lock. This
-         * preparation involves construction of a PlanExecutor. Construction of a PlanExecutor
-         * requires the database lock because it goes through query planning and optimization,
-         * which may involve partial execution of the delete plan tree.
-         *
-         * On success, a non-NULL PlanExecutor will be available via getPlanExecutor().
-         */
-        Status prepareInLock(Database* db);
-
-        /**
-         * Retrieve the PlanExecutor that will be used to execute this delete upon calling
-         * execute(). Returns NULL if no PlanExecutor has been created.
-         */
-        PlanExecutor* getPlanExecutor();
-
-        /**
-         * Execute a delete.  Requires the caller to hold the database lock on the
-         * appropriate resources for the request.
-         *
-         * Returns the number of documents deleted.
-         */
-        long long execute(Database* db);
-
-    private:
-        // Transactional context.  Not owned by us.
-        OperationContext* _txn;
-
-        // Unowned pointer to the request object that this executor will process.
-        const DeleteRequest* const _request;
-
-        // Parsed query object, or NULL if the query proves to be an id hack query.
-        std::auto_ptr<CanonicalQuery> _canonicalQuery;
-
-        // The tree of execution stages which will be used to execute the update.
-        boost::scoped_ptr<PlanExecutor> _exec;
-
-        // Flag indicating if the query has been successfully parsed.
-        bool _isQueryParsed;
-
-    };
-
-}  // namespace mongo
diff --git a/src/mongo/db/ops/parsed_delete.cpp b/src/mongo/db/ops/parsed_delete.cpp
new file mode 100644
index 00000000000..da1b2c77a25
--- /dev/null
+++ b/src/mongo/db/ops/parsed_delete.cpp
@@ -0,0 +1,104 @@
+/**
+ *    Copyright (C) 2014 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kWrite
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/ops/parsed_delete.h"
+
+#include "mongo/db/catalog/collection.h"
+#include "mongo/db/catalog/database.h"
+#include "mongo/db/exec/delete.h"
+#include "mongo/db/ops/delete_request.h"
+#include "mongo/db/query/canonical_query.h"
+#include "mongo/db/query/get_executor.h"
+#include "mongo/db/query/query_planner_common.h"
+#include "mongo/db/repl/repl_coordinator_global.h"
+#include "mongo/util/assert_util.h"
+#include "mongo/util/log.h"
+#include "mongo/util/mongoutils/str.h"
+
+namespace mongo {
+
+    ParsedDelete::ParsedDelete(OperationContext* txn, const DeleteRequest* request) :
+        _txn(txn),
+        _request(request) { }
+
+    Status ParsedDelete::parseRequest() {
+        dassert(!_canonicalQuery.get());
+
+        if (CanonicalQuery::isSimpleIdQuery(_request->getQuery())) {
+            return Status::OK();
+        }
+
+        return parseQueryToCQ();
+    }
+
+    Status ParsedDelete::parseQueryToCQ() {
+        dassert(!_canonicalQuery.get());
+
+        CanonicalQuery* cqRaw;
+        const WhereCallbackReal whereCallback(_txn, _request->getNamespaceString().db());
+
+        Status status = CanonicalQuery::canonicalize(_request->getNamespaceString().ns(),
+                                                     _request->getQuery(),
+                                                     _request->isExplain(),
+                                                     &cqRaw,
+                                                     whereCallback);
+
+        if (status.isOK()) {
+            cqRaw->setIsForWrite(true);
+            _canonicalQuery.reset(cqRaw);
+        }
+
+        return status;
+    }
+
+    const DeleteRequest* ParsedDelete::getRequest() const {
+        return _request;
+    }
+
+    bool ParsedDelete::canYield() const {
+        return !_request->isGod() &&
+            PlanExecutor::YIELD_AUTO == _request->getYieldPolicy() && (
+            _canonicalQuery.get() ?
+            !QueryPlannerCommon::hasNode(_canonicalQuery->root(), MatchExpression::ATOMIC) :
+            !LiteParsedQuery::isQueryIsolated(_request->getQuery()));
+    }
+
+    bool ParsedDelete::hasParsedQuery() const {
+        return _canonicalQuery.get() != NULL;
+    }
+
+    CanonicalQuery* ParsedDelete::releaseParsedQuery() {
+        invariant(_canonicalQuery.get() != NULL);
+        return _canonicalQuery.release();
+    }
+
+}  // namespace mongo
diff --git a/src/mongo/db/ops/parsed_delete.h b/src/mongo/db/ops/parsed_delete.h
new file mode 100644
index 00000000000..c117db28cb7
--- /dev/null
+++ b/src/mongo/db/ops/parsed_delete.h
@@ -0,0 +1,109 @@
+/**
+ *    Copyright (C) 2014 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/base/disallow_copying.h"
+#include "mongo/base/status.h"
+#include "mongo/db/query/plan_executor.h"
+
+namespace mongo {
+
+    class CanonicalQuery;
+    class Database;
+    class DeleteRequest;
+    class OperationContext;
+
+    /**
+     * This class takes a pointer to a DeleteRequest, and converts that request into a parsed form
+     * via the parseRequest() method. A ParsedDelete can then be used to retrieve a PlanExecutor
+     * capable of executing the delete.
+     *
+     * A delete request is parsed to a CanonicalQuery, so this class is a thin, delete-specific
+     * wrapper around canonicalization.
+     *
+     * No locks need to be held during parsing.
+     */
+    class ParsedDelete {
+        MONGO_DISALLOW_COPYING(ParsedDelete);
+    public:
+        /**
+         * Constructs a parsed delete.
+         *
+         * The object pointed to by "request" must stay in scope for the life of the constructed
+         * ParsedDelete.
+         */
+        ParsedDelete(OperationContext* txn, const DeleteRequest* request);
+
+        /**
+         * Parses the delete request to a canonical query. On success, the parsed delete can be
+         * used to create a PlanExecutor capable of executing this delete.
+         */
+        Status parseRequest();
+
+        /**
+         * As an optimization, we do not create a canonical query if the predicate is a simple
+         * _id equality. This method can be used to force full parsing to a canonical query,
+         * as a fallback if the idhack path is not available (e.g. no _id index).
+         */
+        Status parseQueryToCQ();
+
+        /**
+         * Get the raw request.
+         */
+        const DeleteRequest* getRequest() const;
+
+        /**
+         * Is this delete allowed to yield?
+         */
+        bool canYield() const;
+
+        /**
+         * As an optimization, we don't create a canonical query for updates with simple _id
+         * queries. Use this method to determine whether or not we actually parsed the query.
+         */
+        bool hasParsedQuery() const;
+
+        /**
+         * Releases ownership of the canonical query to the caller.
+         */
+        CanonicalQuery* releaseParsedQuery();
+
+    private:
+        // Transactional context.  Not owned by us.
+        OperationContext* _txn;
+
+        // Unowned pointer to the request object that this executor will process.
+        const DeleteRequest* const _request;
+
+        // Parsed query object, or NULL if the query proves to be an id hack query.
+        std::auto_ptr<CanonicalQuery> _canonicalQuery;
+
+    };
+
+}  // namespace mongo