Description
This wait occurs while a request is waiting to acquire an exclusive lock. It typically accumulates while requests are being blocked by a write transaction (implicit or explicit). When transactions are kept open for extended periods of time it can cause long delays for other requests
Resolved by
DBAs and Developers
Suggested solutions
- Keep transaction durations short.
- Ensure that transaction isolation levels are appropriate (avoid SERIALIZEABLE and REPEATABLE READ if possible)
- Investigate enabling the READ_COMMITTED_SNAPSHOT database setting
- Run trace/Profiler/Extended Event session in conjunction with Blocked Process Threshold to determine which queries are being blocked
- Indexing, ensure that long running queries and transactions are optimized
- Ensure that row, page and table locks are being escalated correctly. If the table is partitioned consider enabling partition escalation
Additional research
Reducing SQL Server Locks
Understanding Isolation Levels
Identify the Cause of SQL Server Blocking
Lock Escalations