Horton

Re: [HACKERS] Custom compression methods

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Ildar Musin <i.musin@postgrespro.ru>
Date: 2017-12-01T19:20:43Z
Lists: pgsql-hackers 
On Fri, Dec 1, 2017 at 10:18 AM, Tomas Vondra
<tomas.vondra@2ndquadrant.com> wrote:
> It has very little impact on this patch, as it has nothing to do with
> columnar storage. That is, each value is compressed independently.

I understand that this patch is not about columnar storage, but I
think the idea that we may want to operate on the compressed data
directly is not only applicable to that case.

> I agree with these thoughts in general, but I'm not quite sure what is
> your conclusion regarding the patch.

I have not reached one.  Sometimes I like to discuss problems before
deciding what I think.  :-)

It does seem to me that the patch may be aiming at a relatively narrow
target in a fairly large problem space, but I don't know whether to
label that as short-sightedness or prudent incrementalism.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

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.