Horton

Re: [HACKERS] Custom compression methods

Alvaro Herrera <alvherre@alvh.no-ip.org>

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From: Alvaro Herrera <alvherre@alvh.no-ip.org>
To: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Cc: Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>, pgsql-hackers@postgresql.org, Ildar Musin <i.musin@postgrespro.ru>
Date: 2017-11-30T20:51:55Z
Lists: pgsql-hackers 
Tomas Vondra wrote:

> On 11/30/2017 04:20 PM, Ildus Kurbangaliev wrote:

> > CREATE COMPRESSION METHOD ts1 FOR tsvector HANDLER
> > tsvector_compression_handler;
> 
> Understood. Good to know you've considered it, and I agree it doesn't
> need to be there from the start (which makes the patch simpler).

Just passing by, but wouldn't this fit in the ACCESS METHOD group of
commands?  So this could be simplified down to
CREATE ACCESS METHOD ts1 TYPE COMPRESSION
we have that for indexes and there are patches flying for heap storage,
sequences, etc.  I think that's simpler than trying to invent all new
commands here.  Then (in a future patch) you can use ALTER TYPE to
define compression for that type, or even add a column-level option to
reference a specific compression method.

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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.