Re: [HACKERS] Custom compression methods

On Tue, 21 Nov 2017 18:47:49 +0100
Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote:

> >   
> 
> Hmmm, it still doesn't work for me. See this:
> 
>     test=# create extension pg_lz4 ;
>     CREATE EXTENSION
>     test=# create table t_lz4 (v text compressed lz4);
>     CREATE TABLE
>     test=# create table t_pglz (v text);
>     CREATE TABLE
>     test=# insert into t_lz4 select repeat(md5(1::text),300);
>     INSERT 0 1
>     test=# insert into t_pglz select * from t_lz4;
>     INSERT 0 1
>     test=# drop extension pg_lz4 cascade;
>     NOTICE:  drop cascades to 2 other objects
>     DETAIL:  drop cascades to compression options for lz4
>     drop cascades to table t_lz4 column v
>     DROP EXTENSION
>     test=# \c test
>     You are now connected to database "test" as user "user".
>     test=# insert into t_lz4 select repeat(md5(1::text),300);^C
>     test=# select * from t_pglz ;
>     ERROR:  cache lookup failed for compression options 16419
> 
> That suggests no recompression happened.

Should be fixed in the attached patch. I've changed your extension a
little bit according changes in the new patch (also in attachments).

Also I renamed few functions, added more comments and simplified the
code related with DefineRelation (thanks to Ildar Musin suggestion).

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