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Message: #07693

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[EP-tech] New system, crashing periodically b/c MySQL Locking

Hi Everybody,

We have a (reasonably) new install that has been grinding to a halt every week or two. When I look at 'top' on the command line (Red Hat) mysqld is hogging 100% CPU. When I use mysqladmin processlist I can see a number of sessions queuing behind this...

| 104558 | doras | localhost | doras | Query   | 1587 | statistics                   | INSERT INTO `cache17312`(`pos`, `eprintid`) SELECT @i:=@i+1, `eprintid` FROM (SELECT `eprint`.`eprin | 0.000    |

The other processes (queued) are all waiting for table level lock and look like this...


| 105134 | doras | localhost | doras | Query   | 487  | Waiting for table level lock | UPDATE `eprint` SET `edit_lock_user`='1037', `edit_lock_since`='1550139932', `edit_lock_until`='1550 | 0.000    |

| 105135 | doras | localhost | doras | Query   | 486  | Waiting for table level lock | SELECT `eprintid`,`rev_number`,`eprint_status`,`userid`,`importid`,`source`,`dir`,`datestamp_year`,` | 0.000  


Eventually the max http processes is reached and the system crashes. The only remedy is to restart httpd and mariadb.


Any ideas what this insert into cache is and why it's locking the the system?

Thanks for any guidance

Fran Callaghan
Dublin City University

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