[pgpool-general: 4311] Re: Pgpool - connection hangs in DISCARD ALL

Gerhard Wiesinger lists at wiesinger.com
Fri Jan 8 16:00:05 JST 2016

On 08.01.2016 07:32, Tatsuo Ishii wrote:
>> On 07.01.2016 22:32, Tatsuo Ishii wrote:
>>> I heard similar reports but problem for developers is, nobody knows
>>> how to reproduce the hang (a stack trace after the hang is not very
>>> helpful).
>> Yes, there were already 2? on the list.
>> I can reproduce it randomly in about one day. I think stack traces
>> should be sufficient when e.g. debug code has been added.
> No. That's just a consequence of many problems including this one.
>> How to track the bug down?
>> Debug code?
>> Enhanced logging?
> A debug logging would be helpful (start pgpool with -d option) but it
> will consume huge disk space if you want to save all off them. Is it
> possible to keep only last 30 minues debug logs before the problem
> occurs? I guess even 10 minutes is enough to know the cause of the
> problem.

Can you try to reproduce it, too?

My use case is very simple:
1.) One persistent connection with username1/database1 doing an insert 
every minute
2.) Nagios bombs out about 10 simple SELECT queries every minute with 
username2/database1 nearly at the same time (so it looks like sometimes 
same backend connection can be used)
So should be easy to test. I close the unused backend connections after 
2s, so if you bomb e.g. every 10s should be fast to reproduce.

Happens in my case in 0.5-24h.


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