[pgpool-general: 1389] Re: pgpool using an out of sync database ?

Tatsuo Ishii ishii at postgresql.org
Thu Feb 14 09:07:24 JST 2013

> Hello,
> I am still testing pgpool before deploying with our production database.
> When one of the databases goes down, my understanding is that it should be
> marked as down by pgpool until we resync it manually. However, in the
> following (admittedly paranoiac) scenario, I think that it does not:
> Here is the case. We have 2 identical computers both running pgpool and
> postgres. Here is sequence of events:
> - we have DB1 and DB2 running fine, perfectly in sync (replication mode)
> - DB2 goes down for some reason and comes back a little later, enough
> though to be marked as down by pgpool
> - we run like that a little while (DB2 now gets seriously out of sync)
> - now, just as a test, do the following:
>     - stop everything (pgpool1, pgpool2, DB1, DB2)
>     - start DB2  and then pgpool2
>     - everything is good, pgpool refuses to use DB2 (which is out of sync)
>    - however, stop and start again pgpool2 (with DB1 down and DB2 up) and
> now pgpool hapilly starts using DB2 (while it was marked out of sync)

> Is that a normal/desired behavior?  I would expect that DB2 should not be
> used until I run a sync manually or I tell pgpool to forget about the
> previous down status.

Pgpool uses DB2 while it is marked out of sync? (or it *was* out of
sync, but now it is in sync?) This should not happen unless you are in
raw mode(that means both replication_mode = off and master_slave_mode
= off).

Any can you please show me pgpool log?
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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