Message for SQL Server Error 845 is "Time-out occurred while waiting for buffer latch type X." Refer to Books Online for more information on this error. This error indicates that a *buffer latch* timeout has occurred in SQL Server when it tried to obtain access (latch) on a specific data page stored in memory (the buffer pool). Latches are internal mechanisms applied by SQL Server to ensure the consistency of pages accessed concurrently. If the requested latch cannot be acquired within the designated timeout period due to contention or locks, this error is raised.
Severity level 17 means that your query encountered resource availability issues at the instance level—not user-level mistakes—and may require DBA intervention because these errors often result from system-level problems like inadequate memory size, storage bottlenecks, I/O subsystem inefficiencies, high degree of parallelism causing contention issues, or other configurations related to concurrency workloads.
When error 845 is encountered, it is important to investigate the underlying cause promptly to prevent potential data corruption or service interruptions. Troubleshooting steps may include analyzing server performance, identifying and resolving resource bottlenecks, adjusting configuration settings, and monitoring system health to prevent similar issues in the future.
Common Causes:
- Not enough available memory leading to frequent cleanup operations in the Buffer Pool during heavy read/writes.
- Slow disk performance might cause delays when fetching/storing pages between physical storage and RAM.
- Heavy multi-threaded workloads can lead to excessive contention over shared resources such as buffers/latches.
- Potential corruption or improperly formatted structure within database files/pages leading to delayed locking.