RE: Very long query planning times for database with lots of partitions

Do you have constraint_exclusion set correctly (i.e. ‘on’ or ‘partition’)?
If so, does the EXPLAIN output mention all of your parent partitions, or are some being successfully pruned?
Planning times can be sped up significantly if the planner can exclude parent partitions, without ever having to examine the constraints of the child (and grandchild) partitions. If this is not the case, take another look at your query and try to figure out why the planner might believe a parent partition cannot be outright disregarded from the query – does the query contain a filter on the parent partitions’ partition key, for example?

I believe Timescaledb has its own query planner optimisations for discarding partitions early at planning time.

Good luck,
Steve.

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