Description:
This may be related to #7424.
The NDB nodes are running on Red Hat ES on Dual Xeon EMT_64 servers with 4gb of RAM
each.
Our tables have DATETIME columns, which are frequently searched. When no index is
defined for a DATETIME column, MAX(), MIN(), ORDER BY, <, and > operators behave
correctly.
When an index is defined, the above operations return incorrect results. MAX(), MIN(),
<, and > returns rows that are not the maximum or minimum of the dataset, or rows that
are not greater than or less than the value specified in the WHERE clause.
How to repeat:
CREATE TABLE `PageData` ( `PageID` bigint(20) unsigned NOT NULL default '0',
`StartLineNumber` bigint(20) unsigned NOT NULL default '0', `EndLineNumber` bigint(20)
unsigned NOT NULL default '0', `StartDateTime` datetime NOT NULL default '0000-00-00
00:00:00', `EndDateTime` datetime NOT NULL default '0000-00-00 00:00:00', `StationID`
smallint(5) unsigned NOT NULL default '0', PRIMARY KEY (`PageID`), KEY `EndDateTime`
(`EndDateTime`)) ENGINE=ndbcluster DEFAULT CHARSET=latin1;
CREATE TABLE `PageDataMyISAM` ( `PageID` bigint(20) unsigned NOT NULL default '0',
`StartLineNumber` bigint(20) unsigned NOT NULL default '0', `EndLineNumber` bigint(20)
unsigned NOT NULL default '0', `StartDateTime` datetime NOT NULL default '0000-00-00
00:00:00', `EndDateTime` datetime NOT NULL default '0000-00-00 00:00:00', `StationID`
smallint(5) unsigned NOT NULL default '0', PRIMARY KEY (`PageID`), KEY `EndDateTime`
(`EndDateTime`)) ENGINE=MYISAM DEFAULT CHARSET=latin1;
[load test data set into each table by redirecting a file of INSERTs into mysql command
line tool]
Running SELECT MIN(EndDateTime),MAX(EndDateTime) FROM PageData; and SELECT
MIN(EndDateTime),MAX(EndDateTime) FROM PageDataMyISAM; produce different results.
Result from SELECT * FROM PageData ORDER BY EndDateTime DESC; produces randomly ordered
rows.
