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Diffstat (limited to 'src/mongo/db/commands/hint_commands.h')
| -rw-r--r-- | src/mongo/db/commands/hint_commands.h | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/src/mongo/db/commands/hint_commands.h b/src/mongo/db/commands/hint_commands.h new file mode 100644 index 00000000000..c0729560551 --- /dev/null +++ b/src/mongo/db/commands/hint_commands.h @@ -0,0 +1,167 @@ +/** + * 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/db/commands.h" +#include "mongo/db/query/query_settings.h" +#include "mongo/db/query/plan_cache.h" + +namespace mongo { + + /** + * DB commands for admin hints. + * Admin hint commands work on a different data structure in the collection + * info cache from the plan cache. + * The user still thinks of admin hint commands as part of the plan cache functionality + * so the command name prefix is still "planCache". + * + * These are in a header to facilitate unit testing. See hint_commands_test.cpp. + */ + + /** + * HintCommand + * Defines common attributes for all admin hint related commands + * such as slaveOk and locktype. + */ + class HintCommand : public Command { + public: + HintCommand(const std::string& name, const std::string& helpText); + + /** + * Entry point from command subsystem. + * Implementation provides standardization of error handling + * such as adding error code and message to BSON result. + * + * Do not override in derived classes. + * Override runPlanCacheCommands instead to + * implement plan cache command functionality. + */ + + bool run(const std::string& dbname, BSONObj& cmdObj, int options, + std::string& errmsg, BSONObjBuilder& result, bool fromRepl); + + /** + * It's fine to return NONE here because plan cache commands + * create explicit read context to access collection info cache. + * Refer to dbcommands.cpp on how locktype() is handled. + */ + virtual LockType locktype() const; + + virtual bool slaveOk() const; + + virtual void help(std::stringstream& ss) const; + + /** + * One action type defined for hint commands: + * - adminHintReadWrite + */ + virtual Status checkAuthForCommand(ClientBasic* client, const std::string& dbname, + const BSONObj& cmdObj); + + /** + * Subset of command arguments used by hint commands + * Override to provide command functionality. + * Should contain just enough logic to invoke run*Command() function + * in admin_hint.h + */ + virtual Status runHintCommand(const std::string& ns, BSONObj& cmdObj, + BSONObjBuilder* bob) = 0; + + private: + std::string helpText; + }; + + /** + * ListHints + * + * { planCacheListHints: <collection> } + * + */ + class ListHints : public HintCommand { + public: + ListHints(); + + virtual Status runHintCommand(const std::string& ns, BSONObj& cmdObj, BSONObjBuilder* bob); + + /** + * Looks up admin hints from collection's query settings. + * Inserts hints into BSON builder. + */ + static Status list(const QuerySettings& querySettings, BSONObjBuilder* bob); + }; + + /** + * ClearHints + * + * { planCacheClearHints: <collection>, query: <query>, sort: <sort>, projection: <projection> } + * + */ + class ClearHints : public HintCommand { + public: + ClearHints(); + + virtual Status runHintCommand(const std::string& ns, BSONObj& cmdObj, BSONObjBuilder* bob); + + /** + * If query shape is provided, clears hints for a query. + * Otherwise, clears collection's query settings. + * Namespace argument ns is ignored if we are clearing the entire cache. + * Removes corresponding entries from plan cache. + */ + static Status clear(QuerySettings* querySettings, PlanCache* planCache, const std::string& ns, + const BSONObj& cmdObj); + }; + + /** + * SetHint + * + * { + * planCacheSetHint: <collection>, + * query: <query>, + * sort: <sort>, + * projection: <projection>, + * indexes: [ <index1>, <index2>, <index3>, ... ] + * } + * + */ + class SetHint : public HintCommand { + public: + SetHint(); + + virtual Status runHintCommand(const std::string& ns, BSONObj& cmdObj, BSONObjBuilder* bob); + + /** + * Sets admin hints for a query shape. + * Removes entry for query shape from plan cache. + */ + static Status set(QuerySettings* querySettings, PlanCache* planCache, const std::string& ns, + const BSONObj& cmdObj); + }; + +} // namespace mongo |