Horton

Re: [HACKERS] Custom compression methods

Ildar Musin <ildar@adjust.com>

View thread View on postgr.es
From: Ildar Musin <ildar@adjust.com>
To: Ildus Kurbangaliev <i.kurbangaliev@gmail.com>
Cc: David Steele <david@pgmasters.net>, Alexander Korotkov <a.korotkov@postgrespro.ru>, Dmitry Dolgov <9erthalion6@gmail.com>, PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Date: 2019-03-18T16:11:01Z
Lists: pgsql-hackers 
Hi Ildus,

On Fri, Mar 15, 2019 at 12:52 PM Ildus Kurbangaliev <
i.kurbangaliev@gmail.com> wrote:

>
> Hi,
> in my opinion this patch is usually skipped not because it is not
> needed, but because of its size. It is not hard to maintain it until
> commiters will have time for it or I will get actual response that
> nobody is going to commit it.
>
> Attached latest set of patches.
>
>
As I understand, the only thing changed since my last review is an
additional
compression method for zlib.

The code looks good. I have one suggestion though. Currently you only
predefine
two compression levels: `best_speed` and `best_compression`. But zlib itself
allows a fine gradation between those two. It is possible to set level to
the
values from 0 to 9 (where zero means no compression at all which I guess
isn't
useful in our case). So I think we should allow user choose between either
textual representation (as you already did) or numeral. Another thing is
that one
can specify, for instance, `best_speed` level, but not `BEST_SPEED`, which
can
be a bit frustrating for user.

Regards,
Ildar Musin

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.