1. On Peer1:
Disable user/application access to Peer1 (allow access only to Peer2)
Copy active config to newconfig
Edit newconfig and exclude column to be dropped from newconfig
e.g. source_user.source_table !(column_to_be_dropped) target_user.target_table target_route
Verify config newconfig
Activate config newconfig
Peer1 is no longer replicating the column to be dropped
Note: At this stage, Peer2 is still replicating to the column to be dropped.
2. On Peer2:
Disable user/application access to Peer2 (allow access only to Peer1)
Copy active config to newconfig
Edit newconfig and exclude column to be dropped from newconfig
e.g. source_user.source_table !(column_to_be_dropped) target_user.target_table target_route
Verify config newconfig
Activate config newconfig
Peer2 is no longer replicating the column to be dropped
Note: At this stage, Peer1 and Peer2 are no longer replicating to the column to be dropped.
3. Drop column:
Ensure there are no backlogs and all queues are clear of messages.
Drop column from Peer2 database
Activate original config on Peer2
Implement the new application (without column) on Peer2
Allow users access to the new application (without column) on Peer2
On Peer1:
Disable user/application access to Peer1 (allow access only to Peer2)
Drop column from Peer1 database
Activate original config on Peer1
Implement the new application (without column) on Peer1
Allow users access to the new application (without column) on Peer1
Note:
At this stage, the column has been removed from replication, dropped on the databases,
and the users are now using the new application (without column) on both Peers.
