[pgpool-general: 9249] Re: pgpool connection timeout

[Tatsuo Ishii]

I didn't say pgpool is irrelevant to the problem. I said #3 is
irrelevant.  So maybe #2 could be relevant. If so I need to know what
happend in #2 and need following information.

>> When the incident happens, can you share the output of pcp_proc_info
>> -a?

>> Is there any non-default setting in pgpool.conf?

> From what we found, the problem is very likely pgpool.
> 
> When we try to run psql -p <pgpool port>, it just hanged without
> response. We were able to run psql  -p <postgres port>.
> 
> Everything resume normal after we restarted pgpool, while no other
> task was restarted.
> 
> On 10/29/24 6:23 PM, Tatsuo Ishii wrote:
>>> Hello,
>>>
>>> Recently our pgpool setup encountered an unexpected performance issue.
>>>
>>> What has happened is as follow:
>>>
>>> 1) There is an application that will make a DB connection via pgpool
>>> to insert new record into a table.
>>> 2) Once the record inserted, the task will close the connection and
>>> wait for the next request.
>>> 3) There was a sudden surge in the total records need to be inserted
>>> into the system.
>>> 4) The task halted its processing as it is unable to make new DB
>>> connection after it closed the previous connection.
>>> 5) All other task that also making DB connection also encountered
>>> connection timeout or DB non responding error.
>>> 6) psql console was not able to establish as well.
>> It seems #3 is totally unrelated to pgpool because the application
>> does not connect at that point. I am puzzled too.
>>
>>> The issue was resolved after we restart pgpool. There was no restart
>>> needed of postgresql.
>>>
>>> There was no error found in pgpool's log, it just has no new
>>> connection came in.  We came to conclude, it seems the available pool
>>> has been used up.
>> When the incident happens, can you share the output of pcp_proc_info
>> -a?
>>
>>> Our end was very puzzled by this incident, since our task does close
>>> the connection before making the next DB call, so how could the pool
>>> be used up when our task will always release/disconnect before making
>>> new connection? Is there any configuration we need to set in pgpool to
>>> better optimise it?
>>>
>>> The version we are using:
>>>
>>> - pgpool-II version 4.5.1 (hotooriboshi)
>>> - psql (PostgreSQL) 15.6
>> Is there any non-default setting in pgpool.conf?
>>
>> Best reagards,
>> --
>> Tatsuo Ishii
>> SRA OSS K.K.
>> English: http://www.sraoss.co.jp/index_en/
>> Japanese:http://www.sraoss.co.jp
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>> http://www.pgpool.net/mailman/listinfo/pgpool-general
> 
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