[pgpool-general: 8350] Re: Jdbc driver harm cache hit ratio

[Tatsuo Ishii]

> Hi,
> 
> I ran query load with two different drivers via pgpool with cache enabled.
> 
> 1. With psychopg2 which generates simple query and I got 91% cache hit
> ratio.
> 2. I ran the same load with jdbc which generates extended query and I got
> 0.03% cache hit ratio.
> 
> Any thoughts? Am I missing some configuration maybe?

Please a section in the manual:

https://www.pgpool.net/docs/latest/en/html/runtime-in-memory-query-cache.html

As explained in the doc, JDBC by default operates in extended query
mode. In the mode the chance to create query cache tends to be smaller
than simple query because query cache will not be created until sync
message is sent from frontend.

Also you might want to inspect pgpool log with log_client_messages and
log_statement enabled to find the timing of sync message being sent
from frontend.

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en.php
Japanese:http://www.sraoss.co.jp