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help / color / mirror / Atom feedFrom: John Naylor <john.naylor@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Simplify abbreviated key hashing during cardinality estimation
Date: Mon, 21 Sep 2026 10:48:29 +0000
Message-ID: <E1x8bZV-00000000dj7-2ODn@gemulon.postgresql.org> (raw)
Simplify abbreviated key hashing during cardinality estimation
In the wake of commit 2a600a93c, Datums are 64-bit values, so
we no longer need to fold the abbreviated key to 32 bits before
hashing. Instead, use murmurhash64(), which is simpler and avoids
a function call. Also replace hash_uint32() with murmurhash32()
in related places.
Author: Aleksander Alekseev <aleksander@tigerdata.com>
Suggested-by: John Naylor <johncnaylorls@gmail.com>
Reviewed-by: Aditya Gollamudi <adigollamudi@gmail.com> (earlier version)
Reviewed-by: Michael Paquier <michael@paquier.xyz> (earlier version)
Discussion: https://postgr.es/m/CAJ7c6TMPhDRQMmkUHPv8oOK97B1mR8NRS61DgjpdaZUPAwaeZQ%40mail.gmail.com
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/d39fda1cc404834781458376173e5293f870e83a
Modified Files
--------------
src/backend/utils/adt/bytea.c | 9 ++-------
src/backend/utils/adt/network.c | 9 ++-------
src/backend/utils/adt/numeric.c | 8 ++------
src/backend/utils/adt/uuid.c | 9 ++-------
src/backend/utils/adt/varlena.c | 9 ++-------
5 files changed, 10 insertions(+), 34 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: john.naylor@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Simplify abbreviated key hashing during cardinality estimation
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