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author | Hari Khalsa <hkhalsa@10gen.com> | 2013-04-22 15:39:24 -0400 |
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committer | Hari Khalsa <hkhalsa@10gen.com> | 2013-04-23 12:13:27 -0400 |
commit | eb04c3299fb9be3afbf01e281ff5d3c3d38ba024 (patch) | |
tree | 491d43d0aaa156beba3b356a3dd003027a428942 /src/mongo/db/index_selection.h | |
parent | 9ce6634e0ffc6757b4f511a11fd46b863d9dc136 (diff) | |
download | mongo-eb04c3299fb9be3afbf01e281ff5d3c3d38ba024.tar.gz |
SERVER-9212 SERVER-8791 kill newCursor and suitability, centralize latter
Diffstat (limited to 'src/mongo/db/index_selection.h')
-rw-r--r-- | src/mongo/db/index_selection.h | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/mongo/db/index_selection.h b/src/mongo/db/index_selection.h new file mode 100644 index 00000000000..e64978f638e --- /dev/null +++ b/src/mongo/db/index_selection.h @@ -0,0 +1,42 @@ +/** +* Copyright (C) 2013 10gen 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/>. +*/ + +#pragma once + +#include "mongo/db/indexkey.h" // for IndexSuitability + +namespace mongo { + + class BSONObj; + class FieldRangeSet; + + /** + * This class is part of query optimization. For a given index (as uniquely described by + * keyPattern) and a given query (queryConstraints) and given sort order (order), return how + * "suitable" the index is for the query + sort. + * + * USELESS indices are never used. + * HELPFUL indices are explored and compared to other HELPFUL indices. + * OPTIMAL indices short-circuit the search process and are always used. + */ + class IndexSelection { + public: + static IndexSuitability isSuitableFor(const BSONObj& keyPattern, + const FieldRangeSet& queryConstraints, + const BSONObj& order); + }; + +} // namespace mongo |