On Mon, 13 May 2024, Dimitrios Apostolou wrote:
On Sat, 11 May 2024, David Rowley wrote:
On Sat, 11 May 2024 at 13:11, Dimitrios Apostolou <jimis@xxxxxxx> wrote:
Indeed that's an awful estimate, the table has more than 1M of unique
values in that column. Looking into pg_stat_user_tables, I can't see the
partitions having been vacuum'd or analyzed at all. I think they should
have been auto-analyzed, since they get a ton of INSERTs
(no deletes/updates though) and I have the default autovacuum settings.
Could it be that autovacuum starts, but never
finishes? I can't find something in the logs.
It's not the partitions getting analyzed you need to worry about for
an ndistinct estimate on the partitioned table. It's auto-analyze or
ANALYZE on the partitioned table itself that you should care about.
If you look at [1], it says "Tuples changed in partitions and
inheritance children do not trigger analyze on the parent table."
Thanks
Do I read that correctly, that I have to setup cron jobs to manually
analyze partitioned tables?
Dimitris
