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BUG#21310 - Trees in SQL causing a "crashed" table with MyISAM storage engine

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An update that used a join of a table to itself and modified the
table on one side of the join reported the table as crashed or
updated wrong rows.

Fixed by creating temporary table for self-joined multi update statement.


mysql-test/r/myisam.result:
  A test case for BUG#21310.
mysql-test/t/myisam.test:
  A test case for BUG#21310.
sql/lock.cc:
  Exclude 'table' param from check.
sql/sql_update.cc:
  Disabling record cache for self-joined multi update statement is wrong.
  The join must only see the table as it was at the beginning of the statement.
  safe_update_on_fly check if it is safe to update first table on the fly, that is
  not creating temporary table. It is possible in case a row from this table is
  never read more than once. safe_update_on_fly now detect self-joined table and
  refuse to update this table on the fly.
This commit is contained in:
unknown
2006-12-20 19:05:35 +04:00
parent 2576c4c0c9
commit 9d85b0a616
4 changed files with 99 additions and 77 deletions
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16
mysql-test/r/myisam.result
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@ -944,3 +944,19 @@ select * from t1;
a
42
drop table t1;
CREATE TABLE t1(a VARCHAR(16));
INSERT INTO t1 VALUES('aaaaaaaa'),(NULL);
UPDATE t1 AS ta1, t1 AS ta2 SET ta1.a='aaaaaaaaaaaaaaaa';
SELECT * FROM t1;
a
aaaaaaaaaaaaaaaa
aaaaaaaaaaaaaaaa
DROP TABLE t1;
CREATE TABLE t1(a INT);
INSERT INTO t1 VALUES(1),(2);
UPDATE t1,t1 AS t2 SET t1.a=t1.a+2 WHERE t1.a=t2.a-1;
SELECT * FROM t1 ORDER BY a;
a
2
3
DROP TABLE t1;