Re: [BUGS] BUG #14738: ALTER SERVER for foregin servers not working

Oops! I lost a race.

At Tue, 11 Jul 2017 10:23:05 +0900, Amit Langote <Langote_Amit_f8@lab.ntt.co.jp> wrote in
<76f1487a-6b8a-61a9-ebd9-8ff047d0ba94@lab.ntt.co.jp>
> On 2017/07/11 1:18, Tom Lane wrote:
> > fcs1@poczta.onet.pl writes:
> >> PostgreSQL version: 9.4.1
> > 
> >> Command like this doesn't take effect:
> >> ALTER SERVER srw_egib_1
> >>   OPTIONS (
> >>     SET host 'localhost',
> >>     SET port '5432',
> >>     SET dbname 'gml2m1');
> >> It changes definition of this server but tables connected to it are still
> >> connected to previous definition of this server, for example:
> > 
> > It would help if you provided a concrete example of misbehavior rather
> > than abstract claims.  However, I *think* this is something we fixed in
> > 9.4.11.
> 
> Perhaps you are referring to the following item fixed in 9.4.11 [1]:
> 
> "Ensure that cached plans are invalidated by changes in foreign-table options"
> 
> ISTM, OP's problem is unrelated.  Steps to reproduce:

Agreed.

> create extension postgres_fdw ;
> create server s1 foreign data wrapper postgres_fdw options (dbname 'db1');
> create server s2 foreign data wrapper postgres_fdw options (dbname 'db2');
> create user mapping for current_user server s1;
> create user mapping for current_user server s2;
> create foreign table t1 (a int) server s1 options (table_name 't1');
> 
> -- in db1
> create table t1 (a) as select 1;
> 
> -- in db2
> create table t1 (a) as select 2;
> 
> -- back in the original database; t1's server s1 connected to db1
> select * from t1;
>  a
> ---
>  1
> (1 row)
> 
> -- make s1 point to db2
> alter server s1 options (set dbname 'db2');
> 
> -- postgres_fdw will still connect to db1
> select * from t1;
>  a
> ---
>  1
> (1 row)
> 
> I think that's because postgres_fdw/connection.c keeps a cache of
> connections and does not invalidate it upon pg_foreign_server and/or
> pg_user_mapping changes.  I think we discussed the possibility of fixing
> this back when the above-mentioned fix was being worked on [2], but it
> went nowhere.
> 
> Thanks,
> Amit
> 
> [1] https://www.postgresql.org/docs/devel/static/release-9-4-11.html
> [2]
> https://www.postgresql.org/message-id/20160405.184408.166437663.horiguchi.kyotaro%40lab.ntt.co.jp

Many thanks for digging out it, that have almost faded out of my
memory..

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center



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