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Bug#44664: valgrind warning for COMMIT_AND_CHAIN and ROLLBACK_AND_CHAIN

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The problem is that the internal variable used to specify a
transaction with consistent read was being used outside the
processing context of a START TRANSACTION WITH CONSISTENT
SNAPSHOT statement. The practical consequence was that a
consistent snapshot specification could leak to unrelated
transactions on the same session.

The solution is to ensure a consistent snapshot clause is
only relied upon for the START TRANSACTION statement.

This is already fixed in a similar way on 6.0.
This commit is contained in:
Davi Arnaut
2009-05-11 20:54:00 -03:00
parent a4fba5727a
commit bbe926057a
3 changed files with 48 additions and 8 deletions
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19
mysql-test/r/consistent_snapshot.result
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@@ -1,6 +1,9 @@
DROP TABLE IF EXISTS t1;
# Establish connection con1 (user=root)
# Establish connection con2 (user=root)
### Test 1:
### - While a consistent snapshot transaction is executed,
### no external inserts should be visible to the transaction.
# Switch to connection con1
CREATE TABLE t1 (a INT) ENGINE=innodb;
START TRANSACTION WITH CONSISTENT SNAPSHOT;
@@ -10,6 +13,9 @@ INSERT INTO t1 VALUES(1);
SELECT * FROM t1;
a
COMMIT;
### Test 2:
### - For any non-consistent snapshot transaction, external
### committed inserts should be visible to the transaction.
DELETE FROM t1;
START TRANSACTION;
# Switch to connection con2
@@ -19,5 +25,18 @@ SELECT * FROM t1;
a
1
COMMIT;
### Test 3:
### - Bug#44664: valgrind warning for COMMIT_AND_CHAIN and ROLLBACK_AND_CHAIN
### Chaining a transaction does not retain consistency level.
START TRANSACTION WITH CONSISTENT SNAPSHOT;
DELETE FROM t1;
COMMIT WORK AND CHAIN;
# Switch to connection con2
INSERT INTO t1 VALUES(1);
# Switch to connection con1
SELECT * FROM t1;
a
1
COMMIT;
# Switch to connection default + close connections con1 and con2
DROP TABLE t1;