[pgpool-general: 3982] Re: Possible connection leak

[Derek]

When I switch back to the old database using the "\c", it creates a new process, rather than reuse the existing old one.

Kind regards,
Derek.

> On 18 Aug 2015, at 12:59 pm, Tatsuo Ishii <ishii at postgresql.org> wrote:
> 
> That's no problem. Because the old one ("Connected" = 0) can accept
> new connection. As long as there are process which have ("Connected" =
> 0), pgpool-II happily accepts new connections.
> 
> You can verify it by setting num_init_children = 2 and do:
> 
> psql db1
> \c db2
> \c db1
> \c db2
> :
> :
> 
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
> 
>> The old one has a value of 0. But remains in the list until the child life time is reached.
>> 
>> Kind regards,
>> Derek.
>> 
>>> On 18 Aug 2015, at 12:46 pm, Tatsuo Ishii <ishii at postgresql.org> wrote:
>>> 
>>> Does not reporduce here. Are sure that "Connected" field is 1 for both
>>> the new and old database?
>>> 
>>> Database     : test2
>>> Username     : t-ishii
>>> Start time   : 2015-08-18 11:40:05
>>> Creation time: 2015-08-18 11:44:17
>>> Major        : 3
>>> Minor        : 0
>>> Counter      : 1
>>> Backend PID  : 6564
>>> Connected    : 1
>>> PID          : 6534
>>> Backend ID   : 0
>>> 
>>> Best regards,
>>> --
>>> Tatsuo Ishii
>>> SRA OSS, Inc. Japan
>>> English: http://www.sraoss.co.jp/index_en.php
>>> Japanese:http://www.sraoss.co.jp
>>> 
>>>> Hi,
>>>> 
>>>> Psql to pgpool. 
>>>> 
>>>> After logging into the Postgres database, then switch to another database, it would have 2 processes according to pcp_proc_info. 
>>>> 
>>>> 
>>>> Kind regards,
>>>> Derek.
>>>> 
>>>> On 18 Aug 2015, at 11:59 am, Tatsuo Ishii <ishii at postgresql.org> wrote:
>>>> 
>>>>>> Hi,
>>>>>> 
>>>>>> I'm current running pgpool-II 3.4.3-1 using pgpoolAdmin 3.4.1 on Rhel7.1.
>>>>>> 
>>>>>> When I connect using psql to database1 via the virtual ip, then later switch over to another database2 using the "\c". Then switch back to database1. Pgpool creates 3 connections, which I can see in pgpoolAdmin->status->processes.
>>>>>> 
>>>>>> If I continue to switch between the two databases, it will continue to increase the number of pgpool connections via the virtual ip. Eventually, these connections timeout when it reaches the child_life_time value or if it reaches the num_init_children limit, it will hang until a connection is available.
>>>>> 
>>>>> I don't know when you say "the number of pgpool connections", these
>>>>> are from client (psql) to pgpool or pgpool to PostgreSQL. Because the
>>>>> former will not increase as long as the number of psql you are using,
>>>>> I assume you are referring to connections from pgpool to
>>>>> PostgreSQL.
>>>>> 
>>>>> The number could increase until num_init_children reaches. However
>>>>> some of process are expected to accept connections from clients. You
>>>>> could verify it by using "show pool_nodes". "pool_connected" column
>>>>> indicates that the process is ready to accept connections from clients
>>>>> (in this case 0).
>>>>> 
>>>>> Please remeber, however, that psql keeps old connection until \c
>>>>> succeeds. For example, if num_init_children = 1, you are never able to
>>>>> use \c.
>>>>> 
>>>>>> I have the connection_cache on.
>>>>>> 
>>>>>> Is there something that I need to set?
>>>>> 
>>>>> You might want to set client_idle_limit.
>>>>> 
>>>>> Best regards,
>>>>> --
>>>>> Tatsuo Ishii
>>>>> SRA OSS, Inc. Japan
>>>>> English: http://www.sraoss.co.jp/index_en.php
>>>>> Japanese:http://www.sraoss.co.jp