Horton

Re: [HACKERS] Custom compression methods

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Alexander Korotkov <a.korotkov@postgrespro.ru>
Cc: Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Евгений Шишкин <itparanoia@gmail.com>, Andres Freund <andres@anarazel.de>, Oleg Bartunov <obartunov@gmail.com>, Craig Ringer <craig@2ndquadrant.com>, Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2017-12-12T20:52:01Z
Lists: pgsql-hackers 
On Mon, Dec 11, 2017 at 1:06 PM, Alexander Korotkov
<a.korotkov@postgrespro.ru> wrote:
> OK, but NOTICE that presumably unexpected table rewrite takes place could be
> still useful.

I'm not going to complain too much about that, but I think that's
mostly a failure of expectation rather than a real problem.  If the
documentation says what the user should expect, and they expect
something else, tough luck for them.

> Also we probably should add some view that will expose compression methods
> whose are currently preserved for columns.  So that user can correctly
> construct SET COMPRESSION query that doesn't rewrites table without digging
> into internals (like directly querying pg_depend).

Yes.  I wonder if \d or \d+ can show it somehow.

-- 
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.