Sorry for late on this, its due to actual Production swap implementation. Though I tested as suggested, I didnt get time to post my reply. After doing vigorous testing by taking into consideration Steve & Jan points, we succeded it without any problem.
This analysis is flawed. The two event numbers are from different origins > and therefore, don't compare to each other. The combination of > ev_origin,ev_seqno can never be higher on any node, than it is on the > origin itself. Yes, my analysis has flaw. Its no where related to SEQ.No...which I analyzed and every node seq.no number is independed by itself. To simulate this problem, Steve and I were pointing out, do the following: > 1. Create your setup as before. > 2. Stop the streaming replication (simulating the network communication > problem) > 3. Update a row on the master and wait for the SYNC to replicate. > 4. Stop the slon processes. DO NOT let the streaming replica catch up with > the now DEAD master. Assume the master and all its data, including WAL, > have become unavailable. > 5. Promote DR-master and do the two store path commands. > 6. Start slon processes. > 7. Update another row on the new master. > 8. Compare table content on master and slave. > You can detect the problem before step 5 by comparing the ev_seqno with > ev_origin=old-master on the DR-master and slave. Whichever is higher should > be promoted to master. In the unlikely case that it is the Slony slave, you > will have to rebuild the DR-master from scratch, though. Yep, I could able to detect before Step 5. In short of our actual production swap, we stopped application(NO DML's) and Slony. Checked DR-master(which is warm standby) is complete sync with Master(primary). Promoted DR-master, did changes to store_path on both the ends. Started slon on both the nodes. Sync catch-up well. We have taken complete care of NOT happening any Step 2 or 3 though .. :) Thanks once again. --Raghav
_______________________________________________ Slony1-general mailing list Slony1-general@lists.slony.info http://lists.slony.info/mailman/listinfo/slony1-general
