Re: Incorrect CHUNKHDRSZ in nodeAgg.c

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>

To: David Rowley <dgrowleyml@gmail.com>, Tom Lane <tgl@sss.pgh.pa.us>

Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>

Date: 2025-01-08T20:50:10Z

Lists: pgsql-hackers

Attachments

v1-0001-HashAgg-use-Bump-context-for-hash-table-entries.patch (text/x-patch) patch v1-0001

On Mon, 2025-01-06 at 12:34 -0800, Jeff Davis wrote:
> If we separate out 4, we can use the Bump allocator for 2 & 3.

Attached POC patch, which reduces memory usage by ~15% for a simple
distinct query on an integer key. Performance is the same or perhaps a
hair faster.

It's not many lines of code, but the surrounding code might benefit
from some refactoring which would make it a bit simpler.

Regards,
	Jeff Davis

Commits

HashAgg: use Bump allocator for hash TupleHashTable entries.
- cc721c459d37 18.0 landed
Fix outdated CHUNKHDRSZ value in nodeAgg.c
- d93bb8163c9c 18.0 landed