Contents Index Transaction log management Using passthrough mode

SQL Remote User's Guide
  Administering SQL Remote for Adaptive Server Enterprise

Making schema changes


Schema changes to tables being replicated by SQL Remote must be made on a quiet system. A quiet system means the following:

Schema changes include changes to publications, such as adding articles or modifying articles. However, creating or dropping subscriptions, and adding or removing remote users do not need to be done on a quiet system.

In the Adaptive Server Enterprise transaction log, there is no information recording table structure changes: the SQL Remote log scanning process gets the table structure from the Adaptive Server Enterprise system tables. Consequently, the Message Agent cannot scan an operation from the transaction log that happened against the old table structure.

Information stored in the stable queue before the schema change uses the old table definitions and information stored after the schema change uses the new table definitions.

Passthrough mode can be used at the same time as the schema change to make sure that schema changes at remote databases occur in the correct sequence.


Contents Index Transaction log management Using passthrough mode