Re: Hash index bucket split bug

From: Peter Geoghegan <pg(at)bowt(dot)ie>
To: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Robert Haas <robertmhaas(at)gmail(dot)com>
Subject: Re: Hash index bucket split bug
Date: 2026-07-09 15:24:59
Message-ID: CAH2-WznKyrDzTA+wvBYw0zbUe9f2JyUOG-Jm368Cs03sgEB_1Q@mail.gmail.com
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On Thu, Jul 9, 2026 at 6:45 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> I am getting following regression diff even after applying the patch:
> -step s1_split: <... completed>
> step s2_scan:
> SELECT count(*) FROM hash_split_test
> WHERE v = (SELECT k FROM hash_split_key);
> @@ -68,3 +67,4 @@
> 11
> (1 row)

This is just a minor test flakiness issue with the isolation test.
Apparently, we need to force a deterministic report position by adding
a no-op step to the splitter's session.

Attached v2 has a more stable version of the isolation test (no other
changes compared to V1). Does this version work for you?

The isolation test is just for illustrative purposes. I don't think
that it's committable.

--
Peter Geoghegan

Attachment Content-Type Size
v2-0001-Fix-hash-index-scans-concurrent-with-bucket-split.patch application/octet-stream 2.7 KB
v2-0002-Add-tests-for-hash-index-scans-concurrent-with-bu.patch application/octet-stream 17.2 KB

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