[pgpool-general: 2440] Re: Kind-mismatch on pg_locks table

Tatsuo Ishii ishii at postgresql.org
Fri Jan 17 07:58:55 JST 2014


Pgpool-II does handle multi statment query very well (stated in the
doc).  As a result your query goes to node 0 and node 1, which causes
the difference of the query result because of the nature of the
SELECT.

Try to not use multi statement query.

Best regards,
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

> Hello,
> 
> I've setup a new PGPool cluster and I'm getting alerts for kind-mismatch on
> the pg_locks table.
> It is my assumption that the pg_locks table will differ between backends as
> pg_pool manages load balanced locking.
> 
> - Do I need to whitelist pg_locks somehow or should I be worried?
> 
> 
> Jan 17 09:19:53 int-pgpool-01 pgpool[831]: connection received: host=[local]
> Jan 17 09:19:53 int-pgpool-01 pgpool[32637]: read_kind_from_backend: 1 th
> kind C does not match with master or majority connection kind D
> Jan 17 09:19:53 int-pgpool-01 pgpool[32637]: kind mismatch among backends.
> Possible last query was: "BEGIN;SET statement_timeout=30000;COMMIT;SELECT
> granted, mode, datname FROM pg_locks l RIGHT JOIN pg_database d ON
> (d.oid=l.database) WHERE d.datallowconn" kind details are: 0[D] 1[C]
> Jan 17 09:19:53 int-pgpool-01 pgpool[32637]: do_child: exits with status 1
> due to error
> Jan 17 09:19:53 int-pgpool-01 pgpool[628]: connection received: host=[local]
> 
> 
>    - PostgreSQL 9.3 (Two backends)
>    - PGPool-II 3.3.1
>    - Replication and load balancing enabled
>    - Debian 7, x64
> 
> 
> Thanks,
> Sam.


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