Comment 8 for bug 1681955

you'll need to check if there is a metric with status='deleted' but never expunged, that's what is blocking upstream gate i believe

i'm not sure what max_pool_size param is for? it seems that the issue we see in gate is that gnocchi is creating too many connections to coordinator. this is because in upstream and it seems downstream too, we dont set coordinator which ends up using mysql/postgresql as the coordination driver. both sql backends i believe set default connections to 100. this should be enough, but tooz locking in mysql/pgsql saves a connection per lock so the more locks that are created, the more connections are opened.

we have a patch to address this in tooz[1] but it's better to not rely on sql coordination i believe.

[1] https://review.openstack.org/#/c/460229/