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mirror of https://github.com/MariaDB/server.git synced 2025-07-30 16:24:05 +03:00

bug #27531: 5.1 part of the fix:

- added join cache indication in EXPLAIN (Extra column).
 - prefer filesort over full scan over 
   index for ORDER BY (because it's faster).
 - when switching from REF to RANGE because
   RANGE uses longer key turn off sort on
   the head table only as the resulting 
   RANGE access is a candidate for join cache
   and we don't want to disable it by sorting
   on the first table only. 


mysql-test/r/archive_gis.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/compress.result:
  bug #27531:
   - join cache in EXPLAIN. 
   - prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ctype_utf8.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/derived.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/distinct.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/func_group.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/func_group_innodb.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/gis.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/greedy_optimizer.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/group_by.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/group_min_max.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/index_merge_myisam.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/information_schema.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/innodb_gis.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/innodb_mysql.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/join.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/join_nested.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/key_diff.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/myisam.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/ndb_condition_pushdown.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/ndb_gis.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/range.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/row.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/select.result:
  bug #27531:
   - join cache in EXPLAIN.
   - prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ssl.result:
  bug #27531:
   - join cache in EXPLAIN.
   - prefer filesort over full scan over index for ORDER BY.
mysql-test/r/ssl_compress.result:
  bug #27531:
   - join cache in EXPLAIN.
   - prefer filesort over full scan over index for ORDER BY.
mysql-test/r/subselect.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/subselect3.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/union.result:
  bug #27531: join cache in EXPLAIN
mysql-test/r/view.result:
  bug #27531: join cache in EXPLAIN
sql/sql_select.cc:
  bug #27531:
   - join cache in EXPLAIN.
   - prefer filesort over full scan over
     index for ORDER BY.
   - disable sorting on the first table only
     when switching from REF to RANGE.
This commit is contained in:
unknown
2007-05-04 18:06:06 +03:00
parent 27aeb9e02b
commit 0c835da803
31 changed files with 216 additions and 202 deletions

View File

@ -57,7 +57,7 @@ a b a b
3 c 3 c
explain select * from t1 as x1, (select * from t1) as x2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY x1 ALL NULL NULL NULL NULL 4
1 PRIMARY x1 ALL NULL NULL NULL NULL 4 Using join cache
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 4
2 DERIVED t1 ALL NULL NULL NULL NULL 4
drop table if exists t2,t3;
@ -188,13 +188,13 @@ pla_id test
105 3
explain SELECT STRAIGHT_JOIN d.pla_id, m2.mat_id FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY m2 ALL NULL NULL NULL NULL 9
1 PRIMARY m2 ALL NULL NULL NULL NULL 9 Using join cache
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using where
2 DERIVED mp ALL NULL NULL NULL NULL 9 Using temporary; Using filesort
2 DERIVED m1 eq_ref PRIMARY PRIMARY 3 test.mp.mat_id 1
explain SELECT STRAIGHT_JOIN d.pla_id, m2.test FROM t1 m2 INNER JOIN (SELECT mp.pla_id, MIN(m1.matintnum) AS matintnum FROM t2 mp INNER JOIN t1 m1 ON mp.mat_id=m1.mat_id GROUP BY mp.pla_id) d ON d.matintnum=m2.matintnum;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY m2 ALL NULL NULL NULL NULL 9
1 PRIMARY m2 ALL NULL NULL NULL NULL 9 Using join cache
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 6 Using where
2 DERIVED mp ALL NULL NULL NULL NULL 9 Using temporary; Using filesort
2 DERIVED m1 eq_ref PRIMARY PRIMARY 3 test.mp.mat_id 1
@ -245,7 +245,7 @@ a a
2 2
explain select * from ( select * from t1 union select * from t1) a,(select * from t1 union select * from t1) b;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 2 Using join cache
1 PRIMARY <derived4> ALL NULL NULL NULL NULL 2
4 DERIVED t1 ALL NULL NULL NULL NULL 2
5 UNION t1 ALL NULL NULL NULL NULL 2
@ -312,7 +312,7 @@ b 3.5000
explain SELECT s.name, AVG(s.val) AS median FROM (SELECT x.name, x.val FROM t1 x, t1 y WHERE x.name=y.name GROUP BY x.name, x.val HAVING SUM(y.val <= x.val) >= COUNT(*)/2 AND SUM(y.val >= x.val) >= COUNT(*)/2) AS s GROUP BY s.name;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY <derived2> ALL NULL NULL NULL NULL 3 Using temporary; Using filesort
2 DERIVED x ALL NULL NULL NULL NULL 17 Using temporary; Using filesort
2 DERIVED x ALL NULL NULL NULL NULL 17 Using temporary; Using filesort; Using join cache
2 DERIVED y ALL NULL NULL NULL NULL 17 Using where
drop table t1;
create table t2 (a int, b int, primary key (a));