[pgpool-hackers: 1670] Re: kind does not match error in pgpool

[Tatsuo Ishii]

>> Thanks for the patch. BTW, I had hard time to test the patch. The
>> original problem report was talking about VACUUM case, but in
>> streaming replication mode, VACUUM is sent to primary node only and
>> kind mismatch error can't happend with VACUUM command.
>>
> 
> The original bug report listed a case where one of the PostgreSQL server
> was throwing a warning message because of transaction wrap around and was
> suggesting to perform vacuum. The original query was not a VACUUM command.

Oh I see.

>> Any suggestion to trigger kind mismatch errors in streaming
>> replication mode?
>>
> 
> Yes I ran into similar issue and mimicking the exact reported scenario and
> getting the transaction wrap around warning is a very hard to generate.
> So I tested the patch by setting the lower value of client_min_messages
> variable on one of the backend servers and also set log_statement = 'all'
> 
> i.e.
> *Backend 1*
> log_statement = 'all'
> client_min_messages = debug2
> 
> *Backend 2*
> log_statement = 'all'
> client_min_messages = notice
> 
> 
> Doing this ensures that one server will always send a original query as a
> log message back to client application. And after that I tested the patch
> using SET commands, since they are sent to all attached backends and
> because of different client_min_messages backend settings I was getting an
> extra log message form backend 1

Clever! Thanks!

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