For more information, see Statistics for Read-Only Access Databases, later in this topic.
Sql balance lock update#
You will need to manually update the statistics on the primary replica. However, there is no auto-update of stale statistics. For memory-optimized tables, the missing statistics are created automatically. In addition, readable secondaries provide robust support for read-only operations, as follows:Īutomatic temporary statistics on readable secondary database optimize read-only queries on disk-based tables. Improves your return on investment for the systems that host readable secondary replicas. If you have mission critical read-workload or the workload that cannot tolerate latency, you should run it on the primary. Offloads your secondary read-only workloads from your primary replica, which conserves its resources for your mission critical workloads. Benefitsĭirecting read-only connections to readable secondary replicas provides the following benefits: For information about read-only routing, see Using a Listener to Connect to a Read-Only Secondary Replica (Read-Only Routing). Though you cannot write data to secondary databases, you can write to read-write databases on the server instance that hosts the secondary replica, including user databases and system databases such as tempdb.Īlways On availability groups also supports the re-routing of read-intent connection requests to a readable secondary replica ( read-only routing). This includes users, database roles, and applications roles together with their respective permissions and transparent data encryption (TDE), if enabled on the primary database. Security settings that occur in the primary databases are persisted to the secondary databases. In many circumstances, data latency between a primary database and the corresponding secondary database is only a few seconds. Furthermore, full-text indexes are synchronized with the secondary databases. For a typical secondary replica, the data, including durable memory optimized tables, in the secondary databases is in near real time. A given secondary database changes as changes on the corresponding primary database are applied to the secondary database.
However, readable secondary databases are not set to read-only. A readable secondary replica allows read-only access to all its secondary databases. A readable secondary replica can be in either synchronous-commit availability mode, or asynchronous-commit availability mode. The Always On availability groups active secondary capabilities include support for read-only access to one or more secondary replicas ( readable secondary replicas).
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