The wait type CLR_RWLOCK_WRITER is ranked #252 by Stedman Solutions and Database Health Monitor. Wait statistics, in the context of SQL Server, refer to the amount of time that a query spends waiting to access data in the database. When a client application requests data from the database, the request is placed in a queue and the client application must wait for its turn to access the data. The time that the query spends waiting is called a "wait" and is tracked by SQL Server. This information can be used to identify potential performance bottlenecks and optimize the performance of the database. Wait statistics are commonly used by database administrators to diagnose and troubleshoot performance issues in SQL Server.
SQL Server uses wait types to indicate where tasks might be delayed. One such wait type, CLR_RWLOCK_WRITER, is related to the Common Language Runtime (CLR). This wait type occurs when a thread is waiting to acquire a write lock on a resource that is being managed by CLR code. In this post, we’ll explain what the CLR_RWLOCK_WRITER wait type means, when it occurs, and how to address it. What Is the CLR_RWLOCK_WRITER Wait Type?The CLR_RWLOCK_WRITER wait type appears when a SQL Server task is attempting to acquire a write lock on a resource used by CLR integration code. CLR integration allows SQL Server to run managed code, such as .NET assemblies, for complex computations or custom functionality. Read-write locks (RW locks) are synchronization mechanisms used to control access to shared resources. A write lock ensures that only one writer thread can modify a resource at a time, preventing conflicts or data corruption. When a thread tries to acquire a write lock but the resource is already locked for reading or writing, it waits, leading to a CLR_RWLOCK_WRITER wait. When Does CLR_RWLOCK_WRITER Appear?This wait type commonly occurs in the following scenarios:
While this wait type is expected in environments with significant CLR usage, frequent or prolonged waits can indicate performance issues. Why CLR_RWLOCK_WRITER Waits MatterProlonged or excessive CLR_RWLOCK_WRITER waits can affect SQL Server performance, especially in workloads relying heavily on CLR functionality. Common causes of high wait times include:
Addressing these waits is essential to maintain performance in CLR-intensive workloads. How to Address CLR_RWLOCK_WRITER WaitsIf CLR_RWLOCK_WRITER waits are impacting your SQL Server environment, consider the following strategies to reduce them:
Monitoring CLR_RWLOCK_WRITER WaitsTo monitor CLR_RWLOCK_WRITER waits, use SQL Server tools such as ConclusionThe CLR_RWLOCK_WRITER wait type in SQL Server occurs when tasks are waiting to acquire a write lock on a resource managed by CLR code. While these waits are expected in environments using CLR integration, frequent or prolonged waits may indicate issues with contention, inefficient CLR code, or unoptimized query plans. By optimizing CLR functionality, reducing contention, and monitoring performance, you can minimize CLR_RWLOCK_WRITER waits and improve overall SQL Server performance. If you need expert help with SQL Server performance tuning, CLR optimization, or resolving wait types, Stedman Solutions offers managed services to keep your SQL Server environment running efficiently and reliably.
Applies toRelated WaitsCLR_AUTO_EVENTCLR_CRST CLR_MONITOR CLR_RWLOCK_READER CLR_TASK_START See AlsoAll Wait Types |