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MWL#110: Make EXPLAIN always show materialization separately

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- Add Item_in_subselect::get_identifier() that returns subquery's id
- Change select_describe() to produce output in new format
- Update test results (checked)
This commit is contained in:
Sergey Petrunya 2010-03-29 18:04:35 +04:00
commit 8a06a7e3a7
11 changed files with 246 additions and 82 deletions
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6
mysql-test/r/subselect_mat.result
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@ -1190,8 +1190,9 @@ INSERT INTO t2 VALUES (13, 1.454);
SET @@optimizer_switch='default,semijoin=on,materialization=on';
EXPLAIN SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t2 ALL NULL NULL NULL NULL 2 Materialize; Scan
1 PRIMARY subselect2 ALL unique_key NULL NULL NULL 2
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 Using where; Using join buffer
2 SUBQUERY t2 ALL NULL NULL NULL NULL 2
SELECT COUNT(*) FROM t1 WHERE (f1,f2) IN (SELECT f1,f2 FROM t2);
COUNT(*)
2
@ -1211,7 +1212,8 @@ SET @@optimizer_switch='default,semijoin=on,materialization=on';
EXPLAIN SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 2
1 PRIMARY t2 range PRIMARY PRIMARY 4 NULL 2 Using index condition; Using MRR; Materialize
1 PRIMARY subselect2 eq_ref unique_key unique_key 5 func 1
2 SUBQUERY t2 range PRIMARY PRIMARY 4 NULL 2 Using index condition; Using MRR
SELECT pk FROM t1 WHERE (a) IN (SELECT a FROM t2 WHERE pk > 0);
pk
2