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Galera Cluster Library
http://galeracluster.com/library/
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GTID gaps possible with manual setting of gtid_next should not happen in MySQL Galera Cluster #493

Closed denis-protivensky closed 2 weeks ago

denis-protivensky commented 3 weeks ago

See https://github.com/codership/mysql-wsrep-bugs/issues/1882.

We should document that GTID gaps may be possible if gtid_next is set to a specific value and a transaction fails. This will cause undefined behavior for Galera Cluster.

One workaround may be to re-assign the same gtid_next value until a transaction succeeds:

# Record some GTID
SET @@SESSION.GTID_NEXT= 'a9264492-7be5-11ef-b353-ca382343a2f9:1';
CREATE TABLE t1 (i INT PRIMARY KEY, j INT) ENGINE=InnoDB;

# Now miss a GTID value by failing a transaction
SET @@SESSION.GTID_NEXT= 'a9264492-7be5-11ef-b353-ca382343a2f9:2';
--error 0, 1824
CREATE TABLE t_fail (i INT PRIMARY KEY, j INT, FOREIGN KEY(j) REFERENCES NON_EXISTING(i)) ENGINE=InnoDB;

# Write successful transaction with the same GTID
SET @@SESSION.GTID_NEXT= 'a9264492-7be5-11ef-b353-ca382343a2f9:2';
DROP TABLE t1;