Description:
Multiple users have reported errors since upgrading to MySQL 4.1.7, specifically it is regarding the HEAP table type.
Error log basically reports
041028 2:21:05 [ERROR] Got error 123 when reading table './vb_database/cpsession'
MySQL error: 123 = Someone has changed the row since it was read; Update with is recoverable
MySQL client library affected are both 4.0 and 4.1 and operating systems that are resulting in this error include FreeBSD, RHEL 3 and Fedora.
Downgrading to MySQL 4.0 resolves this issue as well as issuing a FLUSH TABLE query prior to the SELECT query.
How to repeat:
CREATE TABLE cpsession (
`userid` int(10) unsigned NOT NULL default '0',
`cphash` varchar(32) NOT NULL default '',
`dateline` int(10) unsigned NOT NULL default '0',
PRIMARY KEY (`userid`,`hash`)
) ENGINE=HEAP DEFAULT CHARSET=latin1;
Run one script randomly inserting data and another selecting
SELECT *
FROM cpsession
WHERE userid = 1
LIMIT 1
Suggested fix:
Correct locking of HEAP tables.
