[pgpool-general: 3978] Re: Possible connection leak

Derek derek_kouch at yahoo.com.au
Tue Aug 18 11:35:53 JST 2015


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,

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

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