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SLONIK MERGE SET(7)    Configuration and Action commands   SLONIK MERGE SET(7)


NAME

       MERGE SET - Merge Slony-I replication    sets together


SYNOPSIS

       MERGE SET (options);


DESCRIPTION

       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 subscribers.

        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 mergeset(integer,integer) .


EXAMPLE

            # 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);
            SUBSCRIBE SET (ID = 999, PROVIDER = 1, RECEIVER = 3);
            MERGE SET ( ID = 1, ADD ID = 999, ORIGIN = 1 );


LOCKING BEHAVIOUR

       No application-visible locking should take place.

DANGEROUS/UNINTUITIVE BEHAVIOUR
       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.


SLONIK EVENT CONFIRMATION BEHAVIOUR

       Slonik waits for the command submitted to the previous event node to be
       confirmed on the specified event node before submitting this command.
       Slonik will also wait for any in progress subscriptions involving the
       ADD ID to be subscribed before submitting the MERGE SET command.


VERSION INFORMATION

       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.

                                18 January 2015            SLONIK MERGE SET(7)

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