[pgpool-general: 3638] Re: PGPool sending r/w queries to wrong DB node
nagata at sraoss.co.jp
Fri Apr 17 19:21:09 JST 2015
On Wed, 15 Apr 2015 09:22:23 -0400
Pablo Sanchez <pablo at blueoakdb.com> wrote:
> [ Comments below, in-line ]
> On 04/15/2015 07:01 AM, Yugo Nagata wrote:
> > Hi,
> Hi Yugo,
> > How did you terminate the DELETE? If you terminated by
> > pg_terminal_backend(), this caused the degerenation. I confirmed
> > this by issuing "SELECT pg_sleep(100)" through pgpool-II.
> Aha! I did terminate the DELETEs as follows:
> SELECT pg_terminate_backend(pid)
> FROM pg_stat_activity
> WHERE query LIKE 'delete%'
> AND state ='active';
> At the time we had this "pgpool.conf" setting:
> fail_over_on_backend_error = on
> As I mentioned earlier in the thread, after the error I've changed it
> fail_over_on_backend_error = off
> With "fail_over_on_backend_error = off", I tried the Unit Test you
> provided and pgpool did not degenerate. :)
> Does pg_cancel_backend() also cause a degeneration?
I tried but this didn't cause it.
> In an effort to improve the documentation ... the current pgpool-II
> user manual doesn't mention anything about a pg_terminate_backend()
> causing a failover.
As a sample of backend communication error, it might be good to
mention pg_terminate_backend and kill command.
> Perhaps we can append to the "fail_over_on_backend_error" section the
> fail_over_on_backend_error V2.3 -
> ... old text here ...
> CAUTION: when set to /on/, a pg_terminate_backend() or
> pg_cancel_backend() will cause a failover.
> Pablo Sanchez - Blueoak Database Engineering, Inc
> Ph: 819.459.1926 Blog: http://pablo-blog.blueoakdb.com
> iNum: 883.5100.0990.1054
Yugo Nagata <nagata at sraoss.co.jp>
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