| From: | solai v <solai(dot)cdac(at)gmail(dot)com> |
|---|---|
| To: | zhang ziming <toren(dot)zhang(at)outlook(dot)com> |
| Cc: | "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Re: [PATCH] postgres_fdw: Fix cost estimation for semi join pushdown |
| Date: | 2026-10-09 07:29:55 |
| Message-ID: | CAF0whueg2ehZ0pAG0TAFt6NPfV3uxNFQQnf=1NCvtQjdDSy0ig@mail.gmail.com |
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| Lists: | pgsql-hackers |
Hi all,
Thank you for the updated v2 patch. I reproduced the issue using the
provided test case. With the unpatched code, the planner chose a local
Hash Semi Join, followed by Sort and Limit, instead of pushing down
the semi-join. After applying the patch, the planner selected a single
Foreign Scan, with the semi-join, filters, ORDER BY, LIMIT, and OFFSET
pushed down to the remote server as intended. I also ran the
postgres_fdw regression tests, including postgres_fdw and
query_cancel, along with the eval_plan_qual isolation test. All three
tests passed. The change looks good to me.
Thank you for addressing this issue.
Regards,
Solai
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