Hi, Slawomir! On Aug 13, pslawek83 wrote:

Hi Guys, is in_predicate_conversion_th going to be re-enabled for release builds in some next mariadb release? If I make pull request, will you take it?   Basically for everyone not aware about the issue, this forced IN-predicate to subquery conversion is de-generating some simple queries so badly that they start to take couple of hours instead of seconds, and there is currently no way of fixing these queries nor to turn this conversion off. Thanks, Slawomir.

Perhaps instead of in_predicate_conversion_threshold, we'd better add an optimizer switch to disable this optimization? I've commented in https://jira.mariadb.org/browse/MDEV-16871 Regards, Sergei VP of MariaDB Server Engineering and security@mariadb.org