4 Apr 2012 17:33
Re: Query to see when Slony is done replicating changes?
Steve Singer <ssinger@...>
2012-04-04 15:33:29 GMT
2012-04-04 15:33:29 GMT
On 12-04-03 01:51 PM, Shaun McCloud wrote: > Hello, > > I’m wondering if its possible to query any of the databases in my > cluster to see when Slony is done replicating changes to a single node. > I was going to use the Acks Outstanding statistic but then realized that > the slave nodes that my controller service is waiting to update (and do > not have Slony running on) will keep adding to that count. If there is > no statistic to query, is my assumption that tables are replicated in > the order they are added to the replication set correct? > Slony replicates SYNC events. Those SYNC events might have associated rows in sl_log_1 or sl_log_2 (that need to be replicated) or there might be no changes associated with a SYNC event. The slon process on the master generates SYNC events x seconds. When that SYNC event is replicated to a slave any data changes will also be replicated to the slave so that the slave is 'caught up' with the master as of that SYNC event. So if node 100 is our master and node 200 is a slave. sl_event ev_origin ,ev_seqno,ev_type,..... 100 , 1, SYNC is generated then you know that this event has been replicated to the slave when the slaves sl_confirm tables has a row like sl_confirm ----------- con_origin, con_received, con_seqno 100, 200, 1 When the confirmation makes it back to the master then the sl_confirm on the master would have that row also > As for why I can’t just let the changes replicate to all slaves at once, > it is because of a no single point of failure for the web app that is > reading the replicated data. > > *Shaun McCloud – Associate Software Developer > Geo-Comm, Inc* > 601 W. Saint Germain St., Saint Cloud, MN 56301 > *Office:* 320.240.0040 *Fax:* 320.240.2389 *Toll Free:* 888.436.2666 > */click here to visit /**/www.geo-comm.com/* <http://www.geo-comm.com/> > > <http://www.linkedin.com/companies/geocomm> <http://twitter.com/_geocomm> > > PThink before you print! > > *Microsoft Certified Desktop Support Technician (MCDST)* > > > > _______________________________________________ > Slony1-general mailing list > Slony1-general@... > http://lists.slony.info/mailman/listinfo/slony1-general