Re: Hash index bucket split bug

From: Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
To: Peter Geoghegan <pg(at)bowt(dot)ie>
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 10:45:17
Message-ID: CAA4eK1+pd3T8ULEF6P-9AzpTCdWMG+ciWYopa+9xjj-urEwmRg@mail.gmail.com
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On Thu, Jul 9, 2026 at 2:10 AM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
>
> Both tests are useful in their own way. The regression test runs
> quickly and so might be worth committing alongside the fix -- but it
> depends on leaving behind an incomplete split. The isolation test
> demonstrates that the bug doesn't hinge upon an incomplete split. The
> incomplete split case is particularly nasty, though, because the
> potential for wrong answers persists until an inserter completes the
> split.
>

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)

I will review the code later.

--
With Regards,
Amit Kapila.

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