[pgpool-general: 2220] Re: More I/O Error in Tomcat

Tatsuo Ishii ishii at postgresql.org
Fri Oct 25 19:48:46 JST 2013

Great information. I would like to add this to our FAQ.
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

>   You might solve that by adding a time-out on the Tomcat side.
>   http://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html
>   What you should set is (AFAIK):
>     minIdle (default is 10, set to 0)
>     timeBetweenEvictionRunsMillis (default 5000)
>     minEvictableIdleTimeMillis    (default 60000)
>   This will try every 5 seconds and close any connections that were
> not used in the last 60 seconds. If you keep the sum of both numbers
> below the client time-out on the pgpool size connections should be
> closed at Tomcat side before they time-out on the pgpool side.
>   It is also beneficial to set the
>     testOnBorrow (default false, set to true)
>     validationQuery (default none, set to 'SELECT version();' no quotes)
>   This will help with connections should they expire while waiting,
> without supplying a disconnected connection to the application.
> 2013/10/25 Josh Berkus <josh at agliodbs.com>:
>> On 10/24/2013 05:22 PM, Tatsuo Ishii wrote:
>>>>> This error happens between Tomcat and pgpool.  I suspect Tomcat
>>>>> establishes persistent connections to pgpool and pgpool disconnects it
>>>>> because client_idle_limit is not 0. Is this your case?
>>>> Yes, that sounds likely.  If we need to disable client_idle_timeout,
>>>> though, the number of DB connections bloats hopelessly; this is an
>>>> application with many databases, so we end up with several idle pgPool
>>>> connections per database.  Without client_idle_timeout, how would we
>>>> handle this?
>>> Why don't you turn off Tomcat side persistent connections?
>> I can check on that as an option.  Might not be feasible.

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