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: Dilip Kumar <dilipbalaut@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, Alexander Korotkov <a.korotkov@postgrespro.ru>, David Steele <david@pgmasters.net>, Ildus Kurbangaliev <i.kurbangaliev@gmail.com>, Dmitry Dolgov <9erthalion6@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-03-17T18:17:42Z
Lists: pgsql-hackers 
Hi,

On 2021-03-17 13:31:14 -0400, Robert Haas wrote:
> On Wed, Mar 17, 2021 at 7:41 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > 0002:
> > - Wrapper over heap_form_tuple and used in ExecEvalRow() and
> > ExecEvalFieldStoreForm()
> 
> Instead of having heap_form_flattened_tuple(), how about
> heap_flatten_values(tupleDesc, values, isnull) that is documented to
> modify the values array? Then instead of replacing the
> heap_form_tuple() calls with a call to heap_form_flattened_tuple(),
> you just insert a call to heap_flatten_values() before the call to
> heap_form_tuple(). I think that might be easier for people looking at
> this code in the future to understand what's happening.

OTOH heap_form_flattened_tuple() has the advantage that we can optimize
it further (e.g. to do the conversion to flattened values in fill_val())
without changing the outside API.

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.