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BUG#20357 - Got error 124 from storage engine using MIN and MAX

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functions in queries

Using MAX()/MIN() on table with disabled indexes (by ALTER TABLE)
results in error 124 (wrong index) from storage engine.

The problem was that optimizer use disabled index to optimize
MAX()/MIN(). Normally it must skip disabled index and perform
table scan.

This patch skips disabled indexes for min/max optimization.
This commit is contained in:
svoj@may.pils.ru
2006-06-21 17:30:59 +05:00
parent 26fa98a2cb
commit 8b98be2844
3 changed files with 31 additions and 0 deletions
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13
mysql-test/r/myisam.result
View File

@ -748,3 +748,16 @@ select count(id1) from t1 where id2 = 10;
count(id1)
5
drop table t1;
CREATE TABLE t1(a TINYINT, KEY(a)) ENGINE=MyISAM;
INSERT INTO t1 VALUES(1);
SELECT MAX(a) FROM t1 IGNORE INDEX(a);
MAX(a)
1
ALTER TABLE t1 DISABLE KEYS;
SELECT MAX(a) FROM t1;
MAX(a)
1
SELECT MAX(a) FROM t1 IGNORE INDEX(a);
MAX(a)
1
DROP TABLE t1;

12
mysql-test/t/myisam.test
View File

@ -705,4 +705,16 @@ select count(*) from t1 where id2 = 10;
select count(id1) from t1 where id2 = 10;
drop table t1;
#
# BUG##20357 - Got error 124 from storage engine using MIN and MAX functions
# in queries
#
CREATE TABLE t1(a TINYINT, KEY(a)) ENGINE=MyISAM;
INSERT INTO t1 VALUES(1);
SELECT MAX(a) FROM t1 IGNORE INDEX(a);
ALTER TABLE t1 DISABLE KEYS;
SELECT MAX(a) FROM t1;
SELECT MAX(a) FROM t1 IGNORE INDEX(a);
DROP TABLE t1;
# End of 4.1 tests

6
sql/opt_sum.cc
View File

@ -673,6 +673,12 @@ static bool find_key_for_maxmin(bool max_fl, TABLE_REF *ref,
{
KEY_PART_INFO *part,*part_end;
key_part_map key_part_to_use= 0;
/*
Perform a check if index is not disabled by ALTER TABLE
or IGNORE INDEX.
*/
if (!table->keys_in_use_for_query.is_set(idx))
continue;
uint jdx= 0;
*prefix_len= 0;
for (part= keyinfo->key_part, part_end= part+keyinfo->key_parts ;