[pgpool-general: 423] Re: pg-pool-3.0.4. -unable to create child processes

[Ludwig Adam]

Dear Tatsuo,

thanks for your quick response!
Can you please elaborate on this bug/ do you have suggestions on how to work around it, until the fixed version finds it way into the Ubuntu repository?

Regarding your other email, ulimit shows unlimited processes.

Best regards,
Ludwig

Mobil gesendet.

-----Original Message-----
From: Tatsuo Ishii [ishii at postgresql.org]
Received: Dienstag, 08 Mai 2012, 2:14
To: Ludwig Adam [ludwig.adam at petafuel.de]
CC: pgpool-general at pgpool.net [pgpool-general at pgpool.net]; EDV [EDV at petafuel.de]
Subject: Re: [pgpool-general: 418] pg-pool-3.0.4. -unable to create child processes

I suspect you hit a bug fixed in 3.0.7:

      - Fix bug that the process exits before unlocking semaphore by a
        signal interrupt. (Tatsuo Ishii)
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp

> Dear list,
>
> we just encountered a production issue with pg-pool-3.0.4.: pg-pool killed all idle childprocesses which were waiting for a connection request and failed to create new ones.
>
> I am unsure why the childs exited:
>
>
> 1)    As we have child_life_time = 300 I guess the childs exited normally after a 5 minute period.
>
> 2)    We did a Config reload on pg_pool, and that could mean also that waiting child processes are killed
>
> but pg_pool did not create new ones. So we were left with ~110 active pg-pool processes (which still seemed to work) but we could make no new connections to pgppol (can't tell if the connections have been queued or not).
> This is what the syslog says:
>
> May  7 15:43:13 pgpool-PrepaidDB-HA1 pgpool: 2012-05-07 15:43:13 LOG:   pid 938: reload config files.
> May  7 15:43:13 pgpool-PrepaidDB-HA1 pgpool: 2012-05-07 15:43:13 LOG:   pid 2707: reload config files.
> May  7 16:09:29 pgpool-PrepaidDB-HA1 pgpool: 2012-05-07 16:09:17 ERROR: pid 938: fork() failed. reason: Resource temporarily unavailable
> May  7 16:09:34 pgpool-PrepaidDB-HA1 pgpool: 2012-05-07 16:09:34 LOG:   pid 29194: connect_inet_domain_socket_by_port: exit request has been sent
> May  7 16:09:34 pgpool-PrepaidDB-HA1 pgpool: 2012-05-07 16:09:34 ERROR: pid 29194: connection to <backendserver ha1 here> (5432) failed
> May  7 16:09:34 pgpool-PrepaidDB-HA1 pgpool: 2012-05-07 16:09:34 ERROR: pid 29194: new_connection: create_cp() failed
> May  7 16:09:34 pgpool-PrepaidDB-HA1 pgpool: 2012-05-07 16:09:34 LOG:   pid 29194: notice_backend_error: 0 fail over request from pid 29194
> May  7 16:30:22 pgpool-PrepaidDB-HA1 heartbeat: [2425]: info: pgpool-prepaiddb-ha1 wants to go standby [all]
>
> We also noticed some high load on the server which may be related to the issue.
>
> Any idea what the the cause of this issue is? Do you recommend setting child_life_time = 0? I think there are some memory leak issues in the 3.0.4 versions.
> 3.0.4 is the latest official version in the Ubuntu repository and we would rather not go to self-compiled versions for reasons of maintenance and compliance.
>
> Best regards,
> Ludwig
>
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