SERVER-8871 admin hints

1 files changed, 145 insertions, 0 deletions

diff --git a/src/mongo/db/query/query_settings.h b/src/mongo/db/query/query_settings.h
new file mode 100644
index 00000000000..a25c8309947
--- /dev/null
+++ b/src/mongo/db/query/query_settings.h
@@ -0,0 +1,145 @@
+/**
+ *    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 <string>
+#include <vector>
+#include <boost/thread/mutex.hpp>
+#include "mongo/base/disallow_copying.h"
+#include "mongo/bson/bsonobj.h"
+#include "mongo/db/query/canonical_query.h"
+#include "mongo/db/query/index_entry.h"
+#include "mongo/platform/unordered_map.h"
+
+namespace mongo {
+
+    /**
+     * Holds allowed indices.
+     */
+    class AllowedIndices {
+    private:
+        MONGO_DISALLOW_COPYING(AllowedIndices);
+    public:
+        AllowedIndices(const std::vector<BSONObj>& indexKeyPatterns);
+        ~AllowedIndices();
+
+        // These are the index key patterns that
+        // we will use to override the indexes retrieved from
+        // the index catalog.
+        std::vector<BSONObj> indexKeyPatterns;
+    };
+
+    /**
+     * Value type for query settings.
+     * Holds:
+     *     query shape (query, sort, projection)
+     *     vector of index specs
+     */
+    class AllowedIndexEntry {
+    private:
+        MONGO_DISALLOW_COPYING(AllowedIndexEntry);
+    public:
+        AllowedIndexEntry(const BSONObj& query, const BSONObj& sort,
+                          const BSONObj& projection,
+                          const std::vector<BSONObj>& indexKeyPatterns);
+        ~AllowedIndexEntry();
+        AllowedIndexEntry* clone() const;
+
+        // _query, _sort and _projection collectively
+        // represent the query shape that we are storing hint overrides for.
+        BSONObj query;
+        BSONObj sort;
+        BSONObj projection;
+
+        // These are the index key patterns that
+        // we will use to override the indexes retrieved from
+        // the index catalog.
+        std::vector<BSONObj> indexKeyPatterns;
+    };
+
+    /**
+     * Holds the admin hints in a collection.
+     */
+    class QuerySettings {
+    private:
+        MONGO_DISALLOW_COPYING(QuerySettings);
+    public:
+        QuerySettings();
+
+        ~QuerySettings();
+
+        /**
+         * Returns true and fills out allowedIndicesOut if a hint is set in the query settings
+         * for the query.
+         * Returns false and sets allowedIndicesOut to NULL otherwise.
+         * Caller owns AllowedIndices.
+         */
+        bool getAllowedIndices(const CanonicalQuery& query,
+                               AllowedIndices** allowedIndicesOut) const;
+
+        /**
+         * Returns copies all overrides for the collection..
+         * Caller owns overrides in vector.
+         */
+        std::vector<AllowedIndexEntry*> getAllAllowedIndices() const;
+
+        /**
+         * Adds or replaces entry in query settings.
+         * If existing entry is found for the same key,
+         * frees resources for existing entry before replacing.
+         */
+        void setAllowedIndices(const CanonicalQuery& canonicalQuery,
+                               const std::vector<BSONObj>& indexes);
+
+        /**
+         * Removes single entry from query settings. No effect if query shape is not found.
+         */
+        void removeAllowedIndices(const CanonicalQuery& canonicalQuery);
+
+        /**
+         * Clears all allowed indices from query settings.
+         */
+        void clearAllowedIndices();
+
+    private:
+        /**
+         * Clears entries without acquiring mutex.
+         */
+        void _clear();
+
+        typedef unordered_map<PlanCacheKey, AllowedIndexEntry*> AllowedIndexEntryMap;
+        AllowedIndexEntryMap _allowedIndexEntryMap;
+
+        /**
+         * Protects data in query settings.
+         */
+        mutable boost::mutex _mutex;
+    };
+
+}  // namespace mongo