CUNY Academic Commons

Downtime after the CAC 2.5.7 upgrade seems to have been caused by the litespeed-cache plugin, which was updated to 7.0.1 during that release. Working with Reclaim, we identified that SHOW TABLES queries may have been the culprit, and investigation into the plugin upgrade confirm that this type of query is introduced into an upgrade routine: https://github.com/litespeedtech/lscache_wp/blob/c12e26c130ace7c1513cd017ca08a5bfaf902bab/src/data.upgrade.func.php#L28

This is pretty much precisely the issue we ran into with Editoria11y previously: #20828 The solution there was to send an upstream PR to use something more efficient, like DESCRIBE. We could do something similar here, though I have no idea whether the Litespeed people are liable to accept this kind of PR. If they don't, we're going to have to add a filter to 'query' that catches these and polyfills them with DESCRIBE or the like.