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| author | David Storch <david.storch@10gen.com> | 2015-04-07 11:01:38 -0400 |
|---|---|---|
| committer | David Storch <david.storch@10gen.com> | 2015-04-10 09:33:11 -0400 |
| commit | cc61da0890124c5fd5943b38d051b1bd4a96b961 (patch) | |
| tree | a6ba163cb984d99f563b87faf8681e7e2d127aff | |
| parent | 6f1f5bbc9fe884b0367752dc661fd88063ecb225 (diff) | |
| download | mongo-cc61da0890124c5fd5943b38d051b1bd4a96b961.tar.gz | |
SERVER-17815 ensure plan ranking tie breaker does not cause an inferior plan to win
(cherry picked from commit 122ceeaf9caca8ac1a93e1bed1a7286315aee0ab)
| -rw-r--r-- | src/mongo/db/query/plan_ranker.cpp | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/mongo/db/query/plan_ranker.cpp b/src/mongo/db/query/plan_ranker.cpp index 01dc6d3cd90..cf89cd170fd 100644 --- a/src/mongo/db/query/plan_ranker.cpp +++ b/src/mongo/db/query/plan_ranker.cpp @@ -200,9 +200,9 @@ namespace mongo { double productivity = static_cast<double>(stats->common.advanced) / static_cast<double>(workUnits); - // Just enough to break a tie. - static const double epsilon = 1.0 / - static_cast<double>(internalQueryPlanEvaluationWorks); + // Just enough to break a tie. Must be small enough to ensure that a more productive + // plan doesn't lose to a less productive plan due to tie breaking. + static const double epsilon = std::min(1.0 / static_cast<double>(10 * workUnits), 1e-4); // We prefer covered projections. // |