Re: Add LZ4 compression in pg_dump

From: gkokolatos(at)pm(dot)me
To: Michael Paquier <michael(at)paquier(dot)xyz>
Cc: Justin Pryzby <pryzby(at)telsasoft(dot)com>, pgsql-hackers(at)lists(dot)postgresql(dot)org, Rachel Heaton <rachelmheaton(at)gmail(dot)com>
Subject: Re: Add LZ4 compression in pg_dump
Date: 2022-11-30 17:11:44
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------- Original Message -------
On Wednesday, November 30th, 2022 at 1:50 AM, Michael Paquier <michael(at)paquier(dot)xyz> wrote:

> On Tue, Nov 29, 2022 at 12:10:46PM +0000, gkokolatos(at)pm(dot)me wrote:
> > Thank you. Please advice if is preferable to split 0002 in two parts.
> > I think not but I will happily do so if you think otherwise.
> This one makes me curious. What kind of split are you talking about?
> If it makes the code review and the git history cleaner and easier, I
> am usually a lot in favor of such incremental changes. As far as I
> can see, there is the switch from the compression integer to
> compression specification as one thing. The second thing is the
> refactoring of cfclose() and these routines, paving the way for 0003.
> Hmm, it may be cleaner to move the switch to the compression spec in
> one patch, and move the logic around cfclose() to its own, paving the
> way to 0003.

Fair enough. The atteched v11 does that. 0001 introduces compression
specification and is using it throughout. 0002 paves the way to the
new interface by homogenizing the use of cfp. 0003 introduces the new
API and stores the compression algorithm in the custom format header
instead of the compression level integer. Finally 0004 adds support for

Besides the version bump in 0003 which can possibly be split out and
as an independent and earlier step, I think that the patchset consists
of coherent units.

> By the way, I think that this 0002 should drop all the default clauses
> in the switches for the compression method so as we'd catch any
> missing code paths with compiler warnings if a new compression method
> is added in the future.


> Anyway, I have applied 0001, adding you as a primary author because
> you did most of it with only tweaks from me for pg_basebackup. The
> docs of pg_basebackup have been amended to mention the slight change
> in grammar, affecting the case where we do not have a detail string.

Very kind of you, thank you.


> --
> Michael

Attachment Content-Type Size
v11-0002-Prepare-pg_dump-internals-for-additional-compres.patch text/x-patch 20.1 KB
v11-0003-Introduce-Compressor-API-in-pg_dump.patch text/x-patch 54.5 KB
v11-0004-Add-LZ4-compression-in-pg_-dump-restore.patch text/x-patch 29.5 KB
v11-0001-Teach-pg_dump-about-compress_spec-and-use-it-thr.patch text/x-patch 35.4 KB

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