[pgpool-general: 3501] Re: pgpool failover problems

[Steve Kuekes]

pgpool is handling the replication

I have

replication_mode = on

in my configuration.  The question is how can the 2 nodes get out of 
sync.  All database access to the Postgres nodes is going through pgpool.

Steve

On 03/06/2015 09:41 AM, Muhammad Usama wrote:
> Hi Steve
>
> What kind of replication are you using between backend nodes?
>
> /*replication_stop_on_mismatch*/ and 
> /*failover_if_affected_tuples_mismatch*/ configuration parameters 
> dictate the behavior of pgpool-II, when the synchronization problem 
>  between PostgreSQL backends is detected. These parameters have 
> nothing to do for keeping the data consistent between nodes. For that 
> you have to check why one of the node lacks behind the other.
>
> Thanks
> Kind regards!
> Muhammad Usama
>
> On Fri, Mar 6, 2015 at 1:42 AM, Steve Kuekes 
> <steve.kuekes at physicianspharmacy.com 
> <mailto:steve.kuekes at physicianspharmacy.com>> wrote:
> > I am running pgpool version pgpool-II version 3.3.2 (tokakiboshi) in
> > replication mode with 2 back ends with load balancing. We have a 
> very busy
> > database and we cannot seem to keep both back ends up for longer 
> that 12-16
> > hours of production.
> >
> > These are the messages I get in the pgpool log when the failover occurs
> >
> > Mar  5 12:50:03 ppasv57 pgpool[1421]: pgpool detected difference of the
> > number of inserted, updated or deleted tuples. Possible last query was:
> > "update ppadata.notebase set ntbmsgcount=$1,ntbupdated=$2 where 
> ntbid=$3"
> > Mar  5 12:50:03 ppasv57 pgpool[1421]: CommandComplete: Number of 
> affected
> > tuples are: 1 0
> > Mar  5 12:50:03 ppasv57 pgpool[1421]: ReadyForQuery: Degenerate 
> backends: 1
> > Mar  5 12:50:03 ppasv57 pgpool[1421]: ReadyForQuery: Number of affected
> > tuples are: 1 0
> > Mar  5 12:50:03 ppasv57 pgpool[1421]: degenerate_backend_set: 1 fail 
> over
> > request from pid 1421
> > Mar  5 12:50:03 ppasv57 pgpool[2896]: starting degeneration. 
> shutdown host
> > ppasv59g(9999)
> > Mar  5 12:50:03 ppasv57 pgpool[2896]: Restart all children
> >
> > This update statement is being done within a postgres transaction and it
> > appears after the failover the transaction was successfully rolled 
> back on
> > both back ends.
> >
> > We have the following options set in the pgpool.conf
> >
> > replication_stop_on_mismatch = on
> > failover_if_affected_tuples_mismatch = on
> >
> > Don't we need to have these options set to make sure that both back ends
> > have exactly the same data?
> >
> > What do I need to do to keep both back ends up?
> >
> > Thanks for any help
> >
> > Steve
> >
> > --
> > Steve Kuekes
> >
> > Physicians Pharmacy Alliance
> > 118 MacKenan Drive, Suite 200
> > Cary, NC  27511
> > 919-465-5801 direct
> > 919-463-5555 main
> > 919-463-5566 fax
> >
> > steve.kuekes at physicianspharmacy.com 
> <mailto:steve.kuekes at physicianspharmacy.com>
> >
> > _______________________________________________
> > pgpool-general mailing list
> > pgpool-general at pgpool.net <mailto:pgpool-general at pgpool.net>
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-- 
Steve Kuekes

Physicians Pharmacy Alliance
118 MacKenan Drive, Suite 200
Cary, NC  27511
919-465-5801 direct
919-463-5555 main
919-463-5566 fax

steve.kuekes at physicianspharmacy.com

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