[Pgpool-general] question on pool_connection_pool_timer: set close time

[Marcelo Martins]

Thank you Tatsuo


Marcelo
Linux/Solaris System Administrator
pglists at zeroaccess.org
http://www.zeroaccess.org

On Oct 2, 2008, at 8:48 PM, Tatsuo Ishii wrote:

>> I'm wondering where does this  "pool_connection_pool_timer" gets its
>> information from? I have checked the  pool_connection_pool.c file and
>> it made it seem like it looks for the "connection_life_time" setting
>> but right now I have no timeouts on my pgpool.conf file so I was
>> expecting that to go away but it hasn't.
>
> connection_life_time is controled by SIGALRM. You could find this
> around line 315 in pool_connection_pool.c:
>
> 	/* no other timer found. set my timer */
> 	pool_debug("pool_connection_pool_timer: set alarm after %d  
> seconds", pool_config->connection_life_time);
> 	pool_signal(SIGALRM, pool_backend_timer_handler);
> 	alarm(pool_config->connection_life_time);
>
>> When that sets the close time it will kill the pgpool child ?
>
> No. (that is controled by "child_life_time")
>
>> or
>>
>> close the connection from pgpool to the backends ?
>
> Yes.
>
>> or
>>
>> close the connection that pgpool has opened from the client (apache  
>> in
>> this case) to pgpool ?
>
> No. (that is controled by "child_idle_limit")
>
>> In regards to "num_init_children" :
>>
>> The pgpool page says the following  "Please note that cancelling a
>> query creates another connection to the backend; thus, a query cannot
>> be cancelled if the connections are full. If you want to ensure that
>> queries can be cancelled, set this value to twice the expected
>> connections."
>>
>> The problem with the above is that if I have num_init_children set to
>> twice the number of max_connections that is set on postgresql then
>> postgresql connection limit can get exceeded!
>
> You really should not do that. I recommend num_init_children to be
> lower than max_connections of PostgreSQL.
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
>
>> pgpool-II 2.1.1
>> ............................................................
>> num_init_children = 250
>> max_pool = 1
>> child_life_time = 300
>> connection_life_time = 0
>> child_max_connections = 0
>> client_idle_limit = 0
>> authentication_timeout = 0
>> replication_mode = true
>> load_balance_mode = true
>> replication_stop_on_mismatch = true
>> replicate_select = false
>> reset_query_list = 'ABORT; RESET ALL; SET SESSION AUTHORIZATION  
>> DEFAULT'
>> connection_cache = true
>> ............................................................
>>
>>
>> Thanks for any help
>> -
>> Marcelo
>>
>> _______________________________________________
>> Pgpool-general mailing list
>> Pgpool-general at pgfoundry.org
>> http://pgfoundry.org/mailman/listinfo/pgpool-general