MySQL Bugs: #39872: mysqld is restarted when execute EXPLAIN ...

Bug #39872	mysqld is restarted when execute EXPLAIN ...
Submitted:	6 Oct 2008 10:14	Modified:	7 Oct 2008 14:12
Reporter:	Lee Wonseok
Status:	Closed
Category:	Server: Cluster	Severity:	S1 (Critical)
Version:	mysql5.1.27-ndb6.3.17	OS:	Sun Solaris
Assigned to:		Target Version:

Description:
i have 2 data node.(NoOfReplicas=2)

mysqld is restarted when execute EXPLAIN ...
error log of this time is below.

081006 16:49:59 - mysqld got signal 11 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help diagnose
the problem, but since we have already crashed, something is definitely wrong
and this may fail.

key_buffer_size=8388600
read_buffer_size=131072
max_used_connections=1
max_threads=500
threads_connected=1
It is possible that mysqld could use up to 
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 1101188 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

081006 16:50:00 mysqld_safe mysqld restarted
081006 16:50:00 [Note] Plugin 'BLACKHOLE' disabled by command line option
081006 16:50:00 [Note] Plugin 'InnoDB' disabled by command line option
081006 16:50:00 [Note] NDB: NodeID is 6, management server 'localhost'
081006 16:50:01 [Note] NDB[0]: no storage nodes connected (timed out)
081006 16:50:01 [Warning] NDB: server id set to zero will cause any other mysqld with bin
log to log with wrong server id
081006 16:50:01 [Note] Starting Cluster Binlog Thread
081006 16:50:01 [Note] Event Scheduler: Loaded 0 events
081006 16:50:01 [Note] /usr/local/mysql/bin/mysqld: ready for connections.
Version: '5.1.27-ndb-6.3.17-cluster-gpl-log'  socket: '/tmp/mysql.sock'  port: 3307  MySQL
Cluster Server (GPL)
2008-10-06 16:50:04 [NdbApi] INFO     -- Flushing incomplete GCI:s < 27159/9

How to repeat:
drop table t1;

CREATE TABLE `t1` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`)
) ENGINE=ndbcluster DEFAULT CHARSET=utf8;

drop table t2;

CREATE TABLE `t2` (
  `id` int(11) NOT NULL,
  `obj_id` int(11) DEFAULT NULL,
  UNIQUE KEY `id` (`id`),
  KEY `obj_id` (`obj_id`)
) ENGINE=ndbcluster DEFAULT CHARSET=utf8;

mysql> explain SELECT t1.id FROM t1 INNER JOIN t2 ON t1.id = t2.id  WHERE t2.obj_id=1;
ERROR 2013 (HY000): Lost connection to MySQL server during query

In addition,
in my.cnf 
ndb_index_stat_enable=1

affer upper setting, please check.

./mtr --mysqld=--ndb-index-stat-enable=1 --start-and-exit --debug ndb_binlog_basic

CREATE TABLE `t1` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  PRIMARY KEY (`id`)
) ENGINE=ndbcluster DEFAULT CHARSET=utf8;
CREATE TABLE `t2` (
  `id` int(11) NOT NULL,
  `obj_id` int(11) DEFAULT NULL,
  UNIQUE KEY `id` (`id`),
  KEY `obj_id` (`obj_id`)
) ENGINE=ndbcluster DEFAULT CHARSET=utf8;
mysql> explain SELECT t1.id FROM t1 INNER JOIN t2 ON t1.id = t2.id 
WHERE t2.obj_id=1;
ERROR 2013 (HY000): Lost connection to MySQL server during query

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/55436

2687 Tomas Ulin	2008-10-06
      bug #39872 - explain causes segv

fixed in 6.2.16 and 6.3.19

Documented bug fix in the NDB-6.216 and NDB-6.3.19 changelogs as follows:

        Executing EXPLAIN SELECT on an NDBCLUSTER table could cause mysqld to
        crash.

Correct version number for ndb-6.2 fix is 6.2.16.

Pushed into 6.0.7-alpha  (revid:tomas.ulin@sun.com-20081006110104-e983qm89ggl9cotv)
(version source revid:tomas.ulin@sun.com-20081015121427-mqe9vyomt1jroewp) (pib:5)