#Database Lock
1 articles
One Query Hung for 54 Minutes, Causing Sitewide 504s via MyISAM Locks
A single 30 MB table caused 504s on every page across the site, even with 9.5 GB of RAM still free — I traced information_schema.PROCESSLIST to a single SELECT that had been stuck for 54 minutes on a MyISAM table, cascading into metadata locks across the server, with an immediate fix and ways to prevent it from happening again.