Provided by: slony1-doc_1.2.15-1_all
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/se‐
quences 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, elimi‐
nating the set ID that was being added.
This operation will refuse to be run if the two sets do not have exact‐
ly the same set of subscribers.
ID = ival
Unique ID of the set to contain the union of the two separate
ADD ID = ival
Unique ID of the set whose objects should be transferred.
ORIGIN = ival
Current origin node for both sets.
This uses “schemadocmergeset( integer, integer )” [not available as a
# Assuming that set 1 has direct subscribers 2 and 3
SUBSCRIBE SET (ID = 999, PROVIDER = 1, RECEIVER = 2);
WAIT FOR EVENT (ORIGIN = 1, CONFIRMED = 2, WAIT ON=1);
SUBSCRIBE SET (ID = 999, PROVIDER = 1, RECEIVER = 3);
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 condi‐
tion 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.
17 November 2008 MERGE SET(7)