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| author | unknown <timour@askmonty.org> | 2010-09-30 18:32:44 +0300 |
|---|---|---|
| committer | unknown <timour@askmonty.org> | 2010-09-30 18:32:44 +0300 |
| commit | 8ec5e13f1f0d56afe42e5ded02baeab7a6a60261 (patch) | |
| tree | aca5a9824a6cc84f957b44ac4f60b4ed52ab2195 /mysql-test/r/subselect3.result | |
| parent | 50888477af5d9f08088e2009dcef2f52d71f1f8e (diff) | |
| download | mariadb-git-8ec5e13f1f0d56afe42e5ded02baeab7a6a60261.tar.gz | |
MWL#89: Cost-based choice between Materialization and IN->EXISTS transformation
Phase 3: Implementation of re-optimization of subqueries with injected predicates
and cost comparison between Materialization and IN->EXISTS strategies.
The commit contains the following known problems:
- The implementation of EXPLAIN has not been re-engineered to reflect the
changes in subquery optimization. EXPLAIN for subqueries is called during
the execute phase, which results in different code paths during JOIN::optimize
and thus in differing EXPLAIN messages for constant/system tables.
- There are some valgrind warnings that need investigation
- Several EXPLAINs with minor differences need to be reconsidered after fixing
the EXPLAIN problem above.
This patch also adds one extra optimizer_switch: 'in_to_exists' for complete
manual control of the subquery execution strategies.
Diffstat (limited to 'mysql-test/r/subselect3.result')
| -rw-r--r-- | mysql-test/r/subselect3.result | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/mysql-test/r/subselect3.result b/mysql-test/r/subselect3.result index cfc18413ee0..39ae0bbb4de 100644 --- a/mysql-test/r/subselect3.result +++ b/mysql-test/r/subselect3.result @@ -840,7 +840,12 @@ x ROW(11, 12) = (SELECT MAX(x), 22) ROW(11, 12) IN (SELECT MAX(x), 22) 1 0 0 2 0 0 11 0 0 -# 2nd and 3rd columns should be same for x == 11 only +# 2nd and 3rd columns should be same +EXPLAIN SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1; +id select_type table type possible_keys key key_len ref rows Extra +1 PRIMARY t1 ALL NULL NULL NULL NULL 3 +3 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used +2 DEPENDENT SUBQUERY NULL NULL NULL NULL NULL NULL NULL No tables used SELECT a AS x, ROW(11, 12) = (SELECT MAX(x), 12), ROW(11, 12) IN (SELECT MAX(x), 12) FROM t1; x ROW(11, 12) = (SELECT MAX(x), 12) ROW(11, 12) IN (SELECT MAX(x), 12) 1 0 0 |