[pgpool-general: 1379] pgpool using an out of sync database ?
gsoucy at 36pix.com
Fri Feb 8 13:06:08 JST 2013
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.
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