Replication Manageability Enhancements
Replication has made manageability enhancements in the following areas:
- New Replication Monitor
- Simplification of the user interface
- Improved identity range management
- Parallel snapshot preparation
- Tracer tokens for transactional publications
- Initializing a transactional subscription from a backup
- Call formats for transactional articles can be modified without reinitializing
- Transactional publications use concurrent snapshots by default
- Increased number of columns allowed in transactional publications
- Improved monitoring statistics for merge subscriptions
- Improvements to snapshots for merge publications with parameterized filters
- Declarative ordering for articles in merge publications
- Conditional delete processing for articles in merge publications
- Improved error messages
New Replication Monitor
Replication Monitor has been completely redesigned for SQL Server 2005. It allows you to monitor the overall health of a replication topology, providing detailed information about the status and performance of publications and subscriptions. For more information, see Monitoring Replication with Replication Monitor.
Simplification of the User Interface
Replication wizards and dialog boxes have been redesigned for SQL Server 2005 to simplify setting up a replication topology. Changes include:
- The New Publication Wizard has 40% fewer pages than its SQL Server 2000 counterpart, streamlining the process of creating a publication.
- The interface for filtering merge publications is simplified.
- The Push Subscription Wizard and Pull Subscription Wizard have been combined into the New Subscription Wizard.
- The New Subscription Wizard allows you to create multiple subscriptions with different properties in a single pass through the wizard. You might still choose to use scripting for very large deployments, but the wizard provides a convenient way to set up multiple subscriptions.
- Scripting is integrated into the wizards.
Improved Identity Range Management
Identity range management has been improved:
- For transactional replication, identity columns are replicated by default as identity columns rather than the base data type. In previous versions of SQL Server, transactional replication with read-only subscriptions replicated identity columns as the base data type, such as int.
- For merge replication, the allocation of identity ranges has been redesigned. The range threshold is no longer used, and each node is allocated a primary range and a secondary range of identities.
For more information, see Replicating Identity Columns.
Parallel Snapshot Preparation
Parallel snapshot preparation involves processing of multiple articles while scripting schema or bulk copying data within the Snapshot Agent, allowing snapshot preparation to occur with greater speed and efficiency. No special options are required to take advantage of this functionality.
Tracer Tokens for Transactional Publications
Replication between multiple servers and databases can be challenging to monitor and manage. SQL Server 2005 provides the new tracer token feature: a token (a small amount of data) is inserted into the Publisher and replicated to Subscribers. Statistics are gathered as the tracer token moves through the system, and these statistics can be queried from system tables. For more information, see Measuring Latency and Validating Connections for Transactional Replication.
Initializing a Transactional Subscription from a Backup
Setting up replication between databases that initially contain large volumes of data can be time-consuming and require large amounts of storage. SQL Server 2005 provides a new publication option that allows any backup taken after the creation of a transactional publication to be restored at the Subscriber, rather than using a snapshot to initialize the subscription. For more information, see Initializing a Transactional Subscription Without a Snapshot.
Call Formats for Transactional Articles Can Be Modified Without Reinitializing
By default, for articles in transactional publications, replication propagates changes to Subscribers using a set of stored procedures. The call syntax used by each procedure determines the structure of the parameters provided to the procedure and how much information is sent to the Subscriber with each data change. The call syntax can now be changed for an article without requiring the reinitialization of subscriptions. For more information about call syntax, see Specifying How Changes Are Propagated for Transactional Articles.
Transactional Publications Use Concurrent Snapshots by Default
In SQL Server 2000 concurrent snapshots were available for transactional publications, but they were not used by default. Concurrent snapshots reduce the amount of time that locks are held during snapshot generation, allowing users to work uninterrupted while snapshot files are created. In SQL Server 2005, concurrent snapshots are used by default; a value of 'concurrent_c' is used for the **@sync\_method** parameter of sp_addpublication (Transact-SQL).
Increased Number of Columns Allowed in Transactional Publications
Transactional publications now allow up to 1000 columns in each published table.
Improved monitoring statistics for merge subscriptions
Merge replication now provides article-level statistics, which give much more detailed information about: how much longer a merge phase will take to complete, how much time was spent processing a given article, the type of connection a Subscriber is using, and other important information. The statistics are displayed in the Synchronization History window in Replication Monitor. For more information, see How to: View Information and Perform Tasks for the Agents Associated With a Subscription (Replication Monitor).
Improvements to Snapshots for Merge Publications with Parameterized Filters
Snapshots for publications with parameterized filters (referred to as "dynamic snapshots" in previous versions) provide Subscribers with the correct partition of data. These snapshots provide high performance, but can be difficult to manage with hundreds or thousands of Subscribers. Merge replication now allows you to pre-generate snapshots for each Subscriber and/or specify that Subscribers can initiate snapshot generation during the initial synchronization. For more information, see Snapshots for Merge Publications with Parameterized Filters.
Declarative Ordering for Articles in Merge Publications
It is now possible to explicitly define the order of article processing during merge synchronization, which is particularly useful if you define referential integrity with triggers and rely on a specific order of triggers firing. For more information, see Specifying the Processing Order of Merge Articles.
Conditional Delete Processing for Articles in Merge Publications
Some applications require that inserts and updates be replicated from a Subscriber to the Publisher, while deletes should not be replicated. Consider a point-of-sale system in which inserts for orders are replicated to the Publisher, and order data is then purged from the Subscriber. Conditional delete processing allows you to specify that deletes to a table at a Subscriber should not be replicated to the Publisher. For more information, see Optimizing Merge Replication Performance with Conditional Delete Tracking.
Improved Error Messages
A large number of error messages have been rewritten, providing more detailed cause and resolution information. There is also additional information available for some errors in the troubleshooting documentation. For more information, see Cause and Resolution of Replication Errors.