Josh, Tom,
Thanks for your explanations.
> In the meantime it seems like the quickest answer for Guillaume might
> be to try to avoid keeping any NULLs in parent_application_id.
I can't do that as the majority of the applications don't have any
parent one. Moreover, we use a third party application and we cannot
modify all its internals.
Anyway, I tried to work on the statistics as you told me and here are
the results:
ccm_perf=# ALTER TABLE acs_objects ALTER COLUMN object_id SET STATISTICS 30;
ALTER TABLE
ccm_perf=# ANALYZE acs_objects;
ANALYZE
ccm_perf=# \i query_section.sql
... correct plan ...
Total runtime: 0.555 ms
So I think I will use this solution for the moment.
Thanks a lot for your help.
Regards
--
Guillaume