Table metadata lock Topic is solved

[mtnpavlas]

After a recent upgrade to Joomla 5.2.5 (from J4) and jEvents 3.6.85, we see a frequent (about 1x/hr, but it's totally random) table lock, which results in jEvents pages (calendar or event details page, etc.) to take forever to load (and they never do, the browser just keeps on spinning). Eventually, the entire site crashes.

Narrowed it down to mySQL/MariaDB freezing with the "Waiting for table metadata lock" error in the processes when it's trying to run the following query:

Code: Select all

ALTER TABLE mtb_jevents_vevdetail MODIFY dtend BIGINT NOT NULL

Once we kill the above process, all of the other mySQL processes clear within seconds, and the site comes happily back online.

I'm assuming it's jEvents triggerig this query, no? Not sure why, though, as the schema already has those parameters, i.e., the dtend field is of BIGINT type and NOT NULL already.

Storage engine on the jEvents tables is MyISAM and collation utf8mb3_general_ci (while the other Joomla tables are InnoDB and utf8mb4_unicode_ci) ... in case that matters.

Also, MariaDB version is: 10.6.19-MariaDB-log
PHP: 8.1.32
LAMP stack on a VPS server

Really at my wits' end - any pointers here please? Posted in the jEvents forum, as well, as we're paying Gold Member, but 2 days later still no reply, sadly. Thank you so much!

[Per Yngve Berg]

You should definitely change all tables to InnoDB and utf8mb4_unicode_ci

Using a mix may cause dificulty comparing values.

[mtnpavlas]

Thank you for the input - I have switched the engine to InnoDB, and there's been no d/b locking / website crashing since (fingers crossed it stays that way). Will continue to work with the jEvents folks on why this offensive query keeps on running in the first place - IMO, there should be no need for altering tables after the initial install/upgrade procedure.
Thank you again - marking resolved.