| From: | Jim Jones <jim(dot)jones(at)uni-muenster(dot)de> |
|---|---|
| To: | Zsolt Parragi <zsolt(dot)parragi(at)percona(dot)com> |
| Cc: | Chao Li <li(dot)evan(dot)chao(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Antonin Houska <ah(at)cybertec(dot)at> |
| Subject: | Re: VACUUM FULL, CLUSTER, and REPACK block on other sessions' temp tables |
| Date: | 2026-03-25 23:00:02 |
| Message-ID: | 9de2a59f-9597-4101-bf34-cf3804752e64@uni-muenster.de |
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| Lists: | pgsql-hackers |
Hi
On 25/03/2026 21:38, Zsolt Parragi wrote:
> Shouldn't the patch also include a tap test to verify that the change
> works / fails without it?
Definitely. I just didn't want to invest much time on tests before
getting feedback on the issue itself.
> + /* Skip temp relations belonging to other sessions */
> + {
> + Oid nsp = get_rel_namespace(index->indrelid);
> +
> + if (!isTempOrTempToastNamespace(nsp) && isAnyTempNamespace(nsp))
> + {
>
> Doesn't this result in several repeated syscache lookups?
>
> There's already a SearchSysCacheExsists1 directly above this, then a
> get_rel_namespace, then an isAnyTempNamespace. While this probably
> isn't performance critical, this should be doable with a single
> SearchSysCache1(RELOID...) and then a few conditions, similarly to the
> else branch below this?
You're right. Although it is not performance critical we can solve it
with a single SearchSysCache1.
PFA v3 with the improved fix (0001) and tests (0002).
Thanks for the review!
Best, Jim
| Attachment | Content-Type | Size |
|---|---|---|
| v3-0001-Skip-other-sessions-temp-tables-in-REPACK-CLUSTER.patch | text/x-patch | 3.7 KB |
| v3-0002-Test-VACUUM-FULL-CLUSTER-and-REPACK-with-locked-t.patch | text/x-patch | 3.7 KB |
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