Horton

Re: [HACKERS] Custom compression methods

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Dilip Kumar <dilipbalaut@gmail.com>, Andres Freund <andres@anarazel.de>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, David Steele <david@pgmasters.net>, Ildus Kurbangaliev <i.kurbangaliev@gmail.com>, Dmitry Dolgov <9erthalion6@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-03-22T23:53:39Z
Lists: pgsql-hackers 
Justin Pryzby <pryzby@telsasoft.com> writes:
> On Mon, Mar 22, 2021 at 03:47:58PM -0400, Robert Haas wrote:
>> Are you sure you're looking at the patch I sent,
>> toast-compression-guc-rmh.patch? I can't help wondering if you applied
>> it to a dirty source tree or got the wrong file or something, because
>> otherwise I don't understand why you're seeing things that I'm not
>> seeing.

> I'm guessing Tom read this hunk as being changes to
> check_default_toast_compression() rather than removing the function ?

Yeah, after looking closer, the diff looks like
check_default_toast_compression is being modified in-place,
whereas actually it's getting replaced by CompressionNameToMethod
which does something entirely different.  I'd also not looked
closely enough at where NO_LZ4_SUPPORT() was being moved to.
My apologies --- I can only plead -ENOCAFFEINE.

			regards, tom lane

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.