Description

This wait occurs when a request is waiting to acquire an Bulk Update lock with the low priority options added in SQL Server 2014. These locks are required to protect the object during bulk copy (eg WITH TABLOCK on bcp, SSIS or BULK INSERT commands). This wait typically occurs when requests are blocked by bulk import operations. The low priority operations must be set to abort blockers for this wait type to accumulate

Resolved by

DBAs

Suggested solutions

1. If possible, run low priority tasks outside regular business hours. Using abort blockers will cause interruption to users and could cause application issues
2. Keep transaction durations short
3. Ensure that transactions isolation levels are appropriate (avoid SERIALIZEABLE and REPEATABLE READ if possible)
4. Investigate enabling the READ_COMMITTED_SNAPSHOT database setting
5. Run trace/Profiler/eXtended event session in conjunction with Blocked Process Threshold to determine which queries are being blocked
6. Indexing, ensure that long running queries and transactions are optimised
7. Ensure that locks are being escalated correctly: row, page or table (if table is partitioned, consider enabling partition escalation)

Additional research

Exploring Low Priority Lock Wait Options
Lock Modes
Reducing SQL Server Locks
Understanding Isolation Levels
Identify the Cause of SQL Server Blocking
Identify the Cause of SQL Server Blocking
Lock Escalations

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