Re: pg_publication_tables show dropped columns

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Re: pg_publication_tables show dropped columns

От:
Tom Lane <tgl@sss.pgh.pa.us>
Дата:
Jaime Casanova  writes:
> Just trying the new column/row filter on v15, I found this issue that
> could be replicated very easily.

Bleah.  Post-beta4 catversion bump, here we come.

> This could be solved by adding a "NOT attisdropped", simple patch
> attached.

That view seems quite inefficient as written --- I wonder if we
can't do better by nuking the join-to-unnest business and putting
the restriction in a WHERE clause on the pg_attribute scan.
The query plan that you get for it right now is certainly awful.

			regards, tom lane

Re: pg_publication_tables show dropped columns

От:
Tom Lane <tgl@sss.pgh.pa.us>
Дата:
"houzj.fnst@fujitsu.com"  writes:
> Here is the new version patch.
> I think the query plan and cost looks better after applying the patch.

LGTM, pushed.

			regards, tom lane

RE: pg_publication_tables show dropped columns

От:
"houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Дата:
On Tuesday, September 6, 2022 11:13 AM Tom Lane  wrote:
> 
> Jaime Casanova  writes:
> > Just trying the new column/row filter on v15, I found this issue that
> > could be replicated very easily.
> 
> Bleah.  Post-beta4 catversion bump, here we come.

Oh, Sorry for the miss.

> > This could be solved by adding a "NOT attisdropped", simple patch
> > attached.
> 
> That view seems quite inefficient as written --- I wonder if we can't do better by
> nuking the join-to-unnest business and putting the restriction in a WHERE
> clause on the pg_attribute scan.
> The query plan that you get for it right now is certainly awful.

I agree and try to improve the query as suggested.

Here is the new version patch.
I think the query plan and cost looks better after applying the patch.

Best regards,
Hou zj

RE: pg_publication_tables show dropped columns

От:
"houzj.fnst@fujitsu.com" <houzj.fnst@fujitsu.com>
Дата:
On Wednesday, September 7, 2022 6:01 AM Tom Lane  wrote:
> Subject: Re: pg_publication_tables show dropped columns
> 
> "houzj.fnst@fujitsu.com"  writes:
> > Here is the new version patch.
> > I think the query plan and cost looks better after applying the patch.
> 
> LGTM, pushed.

Thanks for pushing.

Best regards,
Hou zj

pg_publication_tables show dropped columns

От:
Jaime Casanova <jcasanov@systemguards.com.ec>
Дата:
Hi everyone,

Just trying the new column/row filter on v15, I found this issue that
could be replicated very easily.

"""
postgres=# create table t1(i serial primary key);
CREATE TABLE
postgres=# alter table t1 drop i;
ALTER TABLE
postgres=# alter table t1 add id serial primary key;
ALTER TABLE
postgres=# create publication pub_t1 for table t1;
CREATE PUBLICATION

postgres=# select * from pg_publication_tables where pubname = 'pub_t1' \gx
-[ RECORD 1 ]---------------------------------
pubname    | pub_t1
schemaname | public
tablename  | t1
attnames   | {........pg.dropped.1........,id}
rowfilter  |
"""

This could be solved by adding a "NOT attisdropped", simple patch
attached.

-- 
Jaime Casanova
Director de Servicios Profesionales
SystemGuards - Consultores de PostgreSQL
FAQ