Provided by: slony1-2-doc_2.0.7-3build1_all bug


       MERGE SET - Merge Slony-I replication sets together


       MERGE SET (options);


       Merge  a  set  of tables and sequences into another one. This function is a workaround for
       the problem that it is not possible to add tables/sequences  to  already-subscribed  sets.
       One may create a temporary set, add the new objects to that, subscribe all nodes currently
       subscribed to the other set to this new one, and then merge the two together,  eliminating
       the set ID that was being added.

       This  operation  will refuse to be run if the two sets do not have exactly the same set of

       ID = ival
              Unique ID of the set to contain the union of the two formerly separate sets.

       ADD ID = ival
              Unique ID of the set whose objects should be transferred into the above set.

       ORIGIN = ival
              Current origin node for both sets.

       This uses “schemadocmergeset(integer, integer)” [not available as a man page].


            # Assuming that node 1 is the origin of set 999 that has direct subscribers 2 and 3
            SUBSCRIBE SET (ID = 999, PROVIDER = 1, RECEIVER = 2);
            SYNC (ID=1);
            WAIT FOR EVENT (ORIGIN = 1, CONFIRMED = 2, WAIT ON=1);
            SUBSCRIBE SET (ID = 999, PROVIDER = 1, RECEIVER = 3);
            SYNC (ID=1);
            WAIT FOR EVENT (ORIGIN = 1, CONFIRMED = 3, WAIT ON=1);
            MERGE SET ( ID = 1, ADD ID = 999, ORIGIN = 1 );


       No application-visible locking should take place.


       Merging takes place based on the configuration on the origin node. If a merge is requested
       while  subscriptions  are  still  being processed, this can cause in-progress subscribers'
       replication to break, as they'll be looking for configuration for this set which the merge
       request deletes. Do not be too quick to merge sets.


       This  command  was  introduced  in Slony-I 1.0.5. In 1.2.1, a race condition was rectified
       where the merge request would be submitted while subscriptions were still  in  process  on
       subscribers; it refuses to merge before subscriptions are complete.

                                         3 December 2011                      SLONIK MERGE SET(7)