[ventolin]

Here's the reason for adding "SET SESSION optimizer_switch = 'derived_merge=off'": https://github.com/xbmc/xbmc/pull/8393#i...-159857118

Unless something has now changed in MySQL 5.7.x, you can either have slow-ish (but working) queries, or queries that are unable to delete from tables in a subquery.

We opted for the working queries. I assume the delete from subquery restriction still exists in MySQL 5.7.18?

Is going back to MySQL 5.6.x an option? Or try MariaDB, maybe it doesn't have a query optimiser from the 1990s.

 Hi Milhouse,

Wish I'd seen Jingai's posts in this thread earlier. I've been struggling with this same problem (e.g. listing the tracks on an album takes upwards of 6 seconds) and had created a thread here - https://forum.kodi.tv/showthread.php?tid...on=newpost - only to have found the diverged_merge culprit recently. 

Am I right in understanding that Kodi should play nicely with MariaDB and that using it might be a possible workaround? I'd had problems with it before: https://forum.kodi.tv/showthread.php?tid=318705