Replication
Limitations and Considerations
Limitations to using transformable subscriptions and considerations to take into account include the following:
- Snapshot data for a transformable subscription is limited to character mode only; native format (which is usually faster to apply) cannot be used with Data Transformation Services (DTS).
- After a publication is enabled for transformable subscriptions, the option cannot be disabled; the existing publication must be deleted and a new one created.
- You cannot use the updatable transactional Subscriber (two-way transactional updates) or queued updating Subscriber feature with transformable subscriptions (transformations are mapped in one direction, from Publisher to Subscriber).
- If an existing DTS package is changed, and Distribution Agent is running in continuous mode, the Distribution Agent must be shut down and restarted for the package changes to take effect.
- Although creating a transformable subscription creates a DTS package, this type of DTS package is not available for execution outside of replication (from DTS Designer or at the command prompt).
- You must have the proper access permissions for executing the DTS package to use a transformable subscription.
- Introducing DTS transformations into the replication data flow may affect performance. Performance will usually be somewhat slower than sending data to a Subscriber without a DTS package.
- If you add or drop columns from a published table by using Add Column or Drop Column on the Filter Columns tab of the publications properties dialog box, or by using sp_repladdcolumn or sp_repldropcolumn, you will also need to drop and recreate the DTS package to reflect changes to the meta data.
- WRITETEXT and UPDATETEXT statements cannot be used to update columns with text, ntext, or image data types.