What's New (Replication)
SQL Server 2008 introduces several new features and improvements to replication.
Peer-to-Peer Transactional Replication
Peer-to-peer replication includes the following significant usability and manageability improvements:
The ability to detect conflicts during synchronization. This option, which is enabled by default, enables the Distribution Agent to detect conflicts and to stop processing changes at the affected node. For more information, see Conflict Detection in Peer-to-Peer Replication.
The ability to add nodes to a replication topology without quiescing the topology.
In earlier versions of SQL Server, you can add a node to a topology and connect the new node to one existing node. To connect the new node to more than one existing node, you must stop all activity in the topology and then make sure that all pending changes are delivered to all nodes. In SQL Server 2008, you can connect the new node to any number of existing nodes without quiescing. This is made possible in the Configure Peer-to-Peer Topology Wizard or by specifying a value of 'init from lsn' for the @sync\_type parameter of sp_addsubscription.
The ability to configure a topology visually in the Configure Peer-to-Peer Topology Wizard.
The new configuration wizard provides a topology viewer that enables you to perform common configuration tasks, such as adding new nodes, deleting nodes, and adding new connections between existing nodes. The viewer is a major improvement over the grid. By using the viewer, you can see exactly how a topology is configured, and you can easily perform the various configuration tasks. For example, you could configure nodes A, B, and C to all connect to each other, and then configure node D to connect only to nodes A and B. You do not have this level of control with the grid because the grid requires all nodes to be connected to each other.
For more information, see How to: Configure Peer-to-Peer Transactional Replication (SQL Server Management Studio) and How to: Configure Peer-to-Peer Transactional Replication (Replication Transact-SQL Programming).
Replication Monitor includes the following usability improvements:
In most Replication Monitor grids, you can now do the following: select which columns to view; sort by multiple columns; and filter rows in the grid based on column values.
To access this functionality: right-click a grid, and then select Choose Columns to Show, Sort, Filter, or Clear Filter. Filter settings are specific to each grid. Column selection and sorting are applied to all grids of the same type, such as the publications grid for each Publisher.
The Common Jobs tab for the Publisher node has been renamed to Agents. The Agents tab now provides a centralized location to view information about all the agents and jobs that are associated with publications at the selected Publisher. Agents and jobs that are associated with publications include the following:
The Snapshot Agent, which is used by all publications.
The Log Reader Agent, which is used by all transactional publications.
The Queue Reader Agent, which is used by transactional publications that are enabled for queued updating subscriptions.
Maintenance jobs, which are used by all publications.
The Distribution Agent and Merge Agent are associated with subscriptions to publications. For more information, see How to: View Information and Perform Tasks for the Agents Associated With a Subscription (Replication Monitor).
The Warnings and Agents tab for the publication node has been split into separate Warnings and Agents tabs. Splitting the tabs emphasizes the difference between administering performance warnings, and monitoring replication agents. The Agents tab refreshes automatically, but the Warnings tab does not.
For more information about Replication Monitor, see Monitoring Replication with Replication Monitor.
Enhanced Transactional Replication Support for Partitioned Tables
In earlier versions of SQL Server, replication supports the publication of partitioned tables. However, you cannot use the SWITCH PARTITION clause of ALTER TABLE to move data between partitions. In SQL Server 2008, transactional replication enables you to execute SWITCH PARTITION commands on the publication database and to optionally have the commands replicated and applied at each Subscriber. For more information, see Replicating Partitioned Tables and Indexes.