Re: Reduce TupleHashEntryData struct size by half

Jeff Davis <pgsql@j-davis.com>

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

To: Heikki Linnakangas <hlinnaka@iki.fi>, pgsql-hackers@postgresql.org

Date: 2025-01-07T23:32:07Z

Lists: pgsql-hackers

Attachments

v3-0001-TupleHashTable-store-additional-data-along-with-t.patch (text/x-patch) patch v3-0001
v3-0002-simplehash-don-t-require-a-status-field.patch (text/x-patch) patch v3-0002
v3-0003-TupleHashTable-reduce-overhead-by-removing-status.patch (text/x-patch) patch v3-0003
v3-0004-Pack-TupleHashEntryData-and-AggStatePerGroupData.patch (text/x-patch) patch v3-0004

On Thu, 2024-11-21 at 12:37 -0800, Jeff Davis wrote:
> 
> New patch series attached.

I committed the earlier cleanup patches and rebased the rest. Attached.

0001 is not quite as clean as I'd like it to be; suggestions welcome.
It does save a pointer per entry, though, which is substantial.

Regards,
	Jeff Davis

Commits

Comment fixups from 626df47ad9.
- a0c7b765372d 18.0 landed
Remove 'additional' pointer from TupleHashEntryData.
- 626df47ad9db 18.0 cited
Add ExecCopySlotMinimalTupleExtra().
- a0942f441ed6 18.0 landed
Create accessor functions for TupleHashEntry.
- 4d143509cbfa 18.0 landed
TupleHashTable: store additional data along with tuple.
- e0ece2a981ee 18.0 landed
ExecInitAgg: update aggstate->numaggs and ->numtrans earlier.
- 3f482940dbcb 18.0 landed
nodeSetOp.c: missing additionalsize for BuildTupleHashTable().
- 32ddfaffd149 18.0 landed
Remove unused TupleHashTableData->entrysize.
- 8a96faedc408 18.0 landed
Add missing typedefs.list entry for AggStatePerGroupData.
- 834c9e807cf1 18.0 landed