[pgpool-general: 7174] Re: Idle connection in database

[Tatsuo Ishii]

Hi Nikhil,

> Hi Tatsuo,
> 
> Thank for the information
> 
>> No. client_idle_limit = 5mins means, clients will be disconnected
>> after 5 minutes idle period, not backend connections.
> 
> Agreed.
> 
>> If you want to terminate idle connections from pgpool to backend, you
>> should use connection_life_time or child_life_time.
> 
>> In your case you already set 600 seconds (that is 10 minutes) to the
>> parameters, and they would be triggered if no clients connect to
>> pgpool within 10 minutes.
> 
> This is not happening, we can see backend connections from 10-12 hours
> before as well.

If you execute "show pool_pools" in a session connected to pgpool, do
you find backend pid (pool_backendpid) appearing in the
pg_stat_actvity output (pid)?

> state |    query     |          backend_start
> -------+--------------+----------------------------------
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.409933 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.409931 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.4094 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.409005 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.40897 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.407784 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.407632 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.407399 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.407044 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:05:35.344228 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.30343 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.300526 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.300472 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.300048 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.29958 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.299185 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.299048 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.298708 +05:30
>  idle  |  DISCARD ALL | 27-JUL-20 18:00:35.296888 +05:30
> 
> Thanks and Regards,
> Nikhil
> 
> On Tue, Jul 28, 2020 at 11:09 AM Tatsuo Ishii <ishii at sraoss.co.jp> wrote:
> 
>> > Hi Team,
>> >
>> > We have set below parameters in pgpool.conf for connections:
>> >
>> >  - serialize_accept = on
>> >  - client_idle_limit = 600
>> >  - child_life_time = 0
>> >  - child_max_connections = 10
>> >  - connection_life_time = 600
>> >  - num_init_children = 4000
>> >  - max_pool = 1
>> >
>> > So after executing a query, as per client_idle_limit  of 5mins, idle
>> > sessions should be disconnected after 5mins
>>
>> No. client_idle_limit = 5mins means, clients will be disconnected
>> after 5 minutes idle period, not backend connections.
>>
>> > but we can still see a lot of
>> > idle connections on the database from pgpool.
>>
>> If you want to terminate idle connections from pgpool to backend, you
>> should use connection_life_time or child_life_time.
>>
>> In your case you already set 600 seconds (that is 10 minutes) to the
>> parameters, and they would be triggered if no clients connect to
>> pgpool within 10 minutes.
>>
>> Best regards,
>> --
>> Tatsuo Ishii
>> SRA OSS, Inc. Japan
>> English: http://www.sraoss.co.jp/index_en.php
>> Japanese:http://www.sraoss.co.jp
>>