Replication changes in SQL Server 2012

Microsoft has not made any major changes to Replication for the last few versions, but with each version there are always a few changes. I have listed some of the most appealing changes below:

New Feature: Replication support for Availability Groups
Replication has been updated to support AlwaysOn. What this means is there are additional functionality to support the primary changing to a different replica. Extended Events support has been added, but it is not currently useful. New stored procedures were introduced to allow you to redirect the publisher to the new primary.

• sp_redirect_publisher
• sp_get_redirected_publisher
• sp_validate_redirected_publisher
• sp_validate_replica_hosts_as_publishers

There are some limitations such as:

• Peer-To-Peer (P2P), bi-directional, reciprocal transactional publications, and Oracle Publishing are not supported.
• A secondary cannot be a publisher
• Must use a shared distributor

Deprecated and Discontinued Features

Oracle publishing has been listed as deprecated

Replicating data from Oracle has never really worked. It has been plagued with performance issues and setup requirements of triggers on Oracle. In SQL Server 2012 a new featured was added named SQL Server 2012 Change Data Capture for Oracle by Attunity. This feature uses Oracle Log Miner instead of triggers and has much lower data latency than with Transactional Replication for Oracle. Microsoft has said CDC for Oracle is one of the reasons that Oracle publishing has been deprecated. This feature looks very promising and I plan to write a blog post going into more detail on CDC for Oracle later on.

• Heterogeneous replication to non-sql server subscribers is deprecated. To move data, create solutions using change data capture and SSIS.
• Updatable subscriptions including immediate updating and queued updating with snapshot and transactional publications are discontinued.