Date: Tue, 7 Nov 2017 12:44:27 +0300
From: Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>
To: Craig Ringer <craig@2ndquadrant.com>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, PostgreSQL Hackers
 <pgsql-hackers@postgresql.org>, Andres Freund <andres@anarazel.de>
Subject: Re: Custom compression methods
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On Thu, 2 Nov 2017 23:02:34 +0800
Craig Ringer <craig@2ndquadrant.com> wrote:

> On 2 November 2017 at 17:41, Ildus Kurbangaliev
> <i.kurbangaliev@postgrespro.ru> wrote:
> 
> > In this patch compression methods is suitable for MAIN and EXTENDED
> > storages like in current implementation in postgres. Just instead
> > only of LZ4 you can specify any other compression method.  
> 
> We've had this discussion before.
> 
> Please read the "pluggable compression support" thread. See you in a
> few days ;) sorry, it's kinda long.
> 
> https://www.postgresql.org/message-id/flat/20130621000900.GA12425%40alap2.anarazel.de#20130621000900.GA12425@alap2.anarazel.de
> 
> IIRC there were some concerns about what happened with pg_upgrade,
> with consuming precious toast bits, and a few other things.
> 

Thank you for the link, I didn't see that thread when I looked over
mailing lists. I read it briefly, and I can address few things
relating to my patch.

Most concerns have been related with legal issues.
Actually that was the reason I did not include any new compression
algorithms to my patch. Unlike that patch mine only provides syntax
and is just a way to give the users use their own compression algorithms
and deal with any legal issues themselves.

I use only one unused bit in header (there's still one free ;), that's
enough to determine that data is compressed or not.

I did found out that pg_upgrade doesn't work properly with my patch,
soon I will send fix for it.

-- 
---
Ildus Kurbangaliev
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company


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