Horton

Re: [HACKERS] Custom compression methods

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Alexander Korotkov <a.korotkov@postgrespro.ru>, David Steele <david@pgmasters.net>, Ildus Kurbangaliev <i.kurbangaliev@gmail.com>, Dmitry Dolgov <9erthalion6@gmail.com>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2020-06-29T16:31:48Z
Lists: pgsql-hackers 
Hi,

On 2020-06-24 07:59:47 -0400, Robert Haas wrote:
> On Tue, Jun 23, 2020 at 4:00 PM Andres Freund <andres@anarazel.de> wrote:
> > https://postgr.es/m/20130621000900.GA12425%40alap2.anarazel.de is a
> > thread with more information / patches further along.
> >
> > I confused this patch with the approach in
> > https://www.postgresql.org/message-id/d8576096-76ba-487d-515b-44fdedba8bb5%402ndquadrant.com
> > sorry for that.  It obviously still differs by not having lower space
> > overhead (by virtue of not having a 4 byte 'va_cmid', but no additional
> > space for two methods, and then 1 byte overhead for 256 more), but
> > that's not that fundamental a difference.
> 
> Wait a minute. Are we saying there are three (3) dueling patches for
> adding an alternate TOAST algorithm? It seems like there is:
> 
> This "custom compression methods" thread - vintage 2017 - Original
> code by Nikita Glukhov, later work by Ildus Kurbangaliev
> The "pluggable compression support" thread - vintage 2013 - Andres Freund
> The "plgz performance" thread - vintage 2019 - Petr Jelinek
> 
> Anyone want to point to a FOURTH implementation of this feature?

To be clear, I don't think the 2003 patch should be considered as being
"in the running".

Greetings,

Andres Freund

Commits

  1. docs: Update TOAST storage docs for configurable compression.

  2. Further tweaking of pg_dump's handling of default_toast_compression.

  3. Fix interaction of TOAST compression with expression indexes.

  4. Tidy up more loose ends related to configurable TOAST compression.

  5. Short-circuit slice requests that are for more than the object's size.

  6. Mostly-cosmetic adjustments of TOAST-related macros.

  7. Remove useless configure probe for <lz4/lz4.h>.

  8. Error on invalid TOAST compression in CREATE or ALTER TABLE.

  9. docs: Fix omissions related to configurable TOAST compression.

  10. More code cleanup for configurable TOAST compression.

  11. Bring configure support for LZ4 up to snuff.

  12. Make compression.sql regression test independent of default.

  13. Use valid compression method in brin_form_tuple

  14. Fix up pg_dump's handling of per-attribute compression options.

  15. Allow configurable LZ4 TOAST compression.

  16. Fix inconsistencies in the code

  17. Mostly-cosmetic improvements in memory chunk header alignment coding.

  18. Allow numeric to use a more compact, 2-byte header in many cases.