There seems to be an optimizer problem in 5.1, if you put a NULL in the IN clause of a SELECT. For example, given the following table: CREATE TABLE foo ( a INT NOT NULL AUTO_INCREMENT, PRIMARY KEY (a) ); Compare these two EXPLAINs: mysql> EXPLAIN * FROM foo WHERE a IN (160000, 160001, 160002)\G… Continue reading Don’t put a NULL in the IN clause in 5.1
Tag: MySQL 5.1
Upgrading MySQL with minimal downtime through Replication
Problem With the release of MySQL 5.1, many DBAs are going to be scheduling downtime to upgrade their MySQL Server. As with all upgrades between major version numbers, it requires one of two upgrade paths: Dump/reload: The safest method of upgrading, but it takes out your server for quite some time, especially if you have… Continue reading Upgrading MySQL with minimal downtime through Replication
Replication with InnoDB and MyISAM Transactions
There’s a change of behaviour in MySQL 5.1.31 for Row Based Replication, if you have InnoDB transactions that also write to a MyISAM (or other non-transactional engine) table. It’s a side effect of fixing Bug #40116. Take this simple example: Transaction 1: INSERT INTO myisam_tbl (item, val) VALUES (1, 0); Transaction 1: INSERT INTO innodb_tbl… Continue reading Replication with InnoDB and MyISAM Transactions