[pgpool-general: 3547] Re: pgpool 3.3.4 not responding to new SQL connections

[Jose Baez]

OK, thanks.

That was it.

After reading documentarion I didn't get properly the connection pool from
pgpool. Now I know "num_init_children" is the number of accepted
connections from Psql clients.

>From what I understand, Pgpool's pool is not similar to other pools where
there are many external connections sharing fewer connections to backend.
Instead, Pgpool accepts external connections and then multiply them to the
backend! I dont get what is the advantage when you've got 'permanent'
external connections (unless the cached connections can be shared among
every child).

Thanks for your work.











On 16 March 2015 at 04:56, Tatsuo Ishii <ishii at postgresql.org> wrote:

> I suspect you run out num_init_children and there's no free pgpool-II
> process to accept new connection. To make sure that you could use ps
> command. For pgpool-II to accept new connections from clients, there
> must be process which looks like something like this:
>
> 17167 pts/2    S      0:00 pgpool: wait for connection request
>
> Best regards,
> --
> Tatsuo Ishii
> SRA OSS, Inc. Japan
> English: http://www.sraoss.co.jp/index_en.php
> Japanese:http://www.sraoss.co.jp
>
> > Hi!
> >
> > I've been using 3.3.4 in a new deployment and from time to time pgpool
> > doesn't reply anything to new PSQL connections.
> > Either with PgAdmin or a JDBC app or PSQL command line, the initial
> > handshake stays frozen. However we can connect to the Psql backends
> > directly throught their local ports.
> >
> > I've got pgpool  right now with *replication mode = on* (but only 1
> active
> > node) and *'connection_cache = on'* with default values for pooling.
> >
> > I cannot guess what's the SQL query that is hanging pgpool process. Is
> > pgpool waiting for some some reply from PSQL? If it is so, why does it
> > block all other connections?
> >
> > Machine resources are OK (5% cpu and 10% RAM used)
> >
> > After 20-30min (not sure) Pgpool accepts again new PSQL connections.
> >
> > I am looking right now at pgpool's log with debug level = 1, but it is a
> > bit hard to understand the errors kind: T, C, etc... and so many lines
> per
> > second.
> >  I'll keep  looking though.
> >
> >
> > Thanks.
>
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