[Pgpool-general] Prepared statement does not exist

[Tatsuo Ishii]

> Hi,
> 
> We are using pgpool-II version 2.2 and postgres 8.3.3.
> 
> Can any body let us know why we get the following notes in the
> database logs when we use pgpool.
> 
> u=postgres h=xx01.xxxx.xxxx.com ERROR:  prepared statement "S_2" already exists

I'm not sure for this part, but for followings I guess it happens
because you have something like:

reset_query_list = 'ABORT;DISCARD ALL'

> u=postgres h=xx01.xxxx.xxxx.com ERROR:  prepared statement "S_3" does not exist
> u=postgres h=xx01.xxxx.xxxx.com ERROR:  prepared statement "S_1" does not exist
> u=postgres h=xx01.xxxx.xxxx.com ERROR:  prepared statement "S_4" does not exist

pgpool tries to drop prepared statements when client disconnect to
pgpool *after* executing quries specified in reset_query_list which
have removed all prepared statements.

To solve the problem, replace "DISCARD ALL" with "DISCARD TEMPORARY"
or whatever you want to use. See DISCARD man pages for details.

Note that "DISCARD ALL" might cause performance degradation because it
helds exclusive lock on a system catalog.
--
Tatsuo Ishii
SRA OSS, Inc. Japan

> We dont see the below errors if we directly connect to the database.
> Pgpool is used for load-balancing whiel slony is used for replication.
> We see many such logs coming continuously. Can any body tell what can
> be done to avoid them and what its impact is?
> 
> Regards,
> Nimesh.
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