Re: Postgresql BDR(Bi-Directional Replication) Latency Monitoring

Hi

I just replied to a fairly similar question here:

http://www.postgresql.org/message-id/CAMsr+YEqeFXDS=AmqBZMopQDFnt+hO50uV-+s854KW9oA-XKkA@mail.gmail.com

and I'll follow up on that thread as it's essentially the same thing.

On 17 March 2015 at 02:27, Bill Brown <billb(at)consistentstate(dot)com> wrote:

> Hi All,
>
> I'm looking at BDR monitoring documentation at this location
> https://wiki.postgresql.org/wiki/BDR_Monitoring
>
> I understand the query in documentation:
>
> select slot_name, plugin, database, active, xmin,
> pg_get_transaction_committime(xmin)
> FROM pg_stat_logical_decoding ;
>
>
> Should be:
>
> select slot_name, plugin, database, active, xmin,
> pg_get_transaction_committime(xmin)
> FROM pg_replication_slots ;
>
>
>
> I am running PostgreSQL 9.4.0 bits on Centos:
>
> postgresql-bdr94-contrib-9.4.0_bdr1-1_2ndQuadrant.el6.x86_64
> postgresql-bdr94-libs-9.4.0_bdr1-1_2ndQuadrant.el6.x86_64
> postgresql-bdr94-bdr-0.8.0beta1-1_2ndQuadrant.el6.x86_64
> postgresql-bdr94-2ndquadrant-redhat-1.0-2.noarch
> postgresql-bdr94-devel-9.4.0_bdr1-1_2ndQuadrant.el6.x86_64
> postgresql-bdr94-server-9.4.0_bdr1-1_2ndQuadrant.el6.x86_64
> postgresql-bdr94-9.4.0_bdr1-1_2ndQuadrant.el6.x86_64
>
>
> We have 3 nodes set-up. We would like to understand the latency between
> nodes.
>
> When using http://oltpbenchmark.com/ to create a load on one node, I
> would expect the 'xmin' value not to be null but is.
>
> What is the best way to monitor replication latency when using Postgresql
> BDR?
>
> Regards,
>
> Bill
>

--
Craig Ringer http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services