Re: Compress prune/freeze records with Delta Frame of Reference algorithm

Evgeny Voropaev <evgeny.voropaev@tantorlabs.com>

From: Evgeny Voropaev <evgeny.voropaev@tantorlabs.com>

To: Andrey Borodin <x4mmm@yandex-team.ru>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>

Date: 2026-03-20T10:05:41Z

Lists: pgsql-hackers

Attachments

v02-0001-Implement-vect-and-uniqsortvect-containers-and-b.patch (text/x-patch) patch v2-0001
v02-0002-Implement-Delta-Frame-of-Reference-compression.patch (text/x-patch) patch v2-0002
v02-0003-Use-Delta-Frame-of-Reference-DFoR-to-compress-pr.patch (text/x-patch) patch v2-0003

Hello Andrey,

 > Great idea and nice library for DFoR! Thank you for your attention.
I wish the patch would be useful.

All your proposals and recommendations have been implemented in v02.
Also the meson settings has been updated for supporting the new
developments.

 > Perhaps, first thing to start is to fix CI failures

Once meson is fixed, tests should pass successfully now. Looking
forward to this.

 > As a minor nit: do not use stdlib assert(), use capital Assert()

Done.

 > Are we 100% sure qsort() won't allocate something anywhere?
 > sort_template.h seems to be allocation-free, but just in case...

No guarantees from libraries or from descriptions about qsort's
behaviour regarding dynamic memory allocation. So, the qsort is just
substituted with the sort_template, which we trust, and as you
proposed.

Waiting for tests to have passed, and then I hope we could move further.

Best regards, Evgeny Voropaev.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Fix a set of typos and grammar issues across the tree
- d3bba0415435 19 (unreleased) cited