Prior to version 12.0, when Replication Server received a data row, the columns that were defined in the replication definition but missing in the data row were sent as null. This could cause the Data Server Interface (DSI) to shutdown when the columns were dropped from the replicate or standby table.
Beginning with version 12.0, to support alter table [add | drop | modify] column, Replication Server sends only the values that are received from the data server. Columns that are defined in the replication definition but missing in the data row are ignored instead of receiving a null value. The exception is when you use custom function-strings. If a missing column value is expected in a custom function-string, then Replication Server will continue to send null for the column.
If you use a column in a subscription or article where clause, you must drop the subscription or article before you can change or drop that column. If you do not use a column in a subscription or article where clause, then you do not need to drop the subscription.
WARNING! You always need to follow the manual procedure specified in “Migration procedure” for alter table [add | drop | modify] columns when subscriptions are involved, or when you use send standby replication definition columns to replicate to a standby database. Failure to do so may cause data loss or Replication Server thread problems.
See “alter
table support for warm standby” on page 117 in the Replication
Server Administration Guide Volume 2 for information
on how Replication Server support Adaptive Server version 12.0 enhancements
to alter table.
