Re: [HACKERS] Custom compression methods

On Tue, 21 Nov 2017 18:47:49 +0100
Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)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).

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