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(Books Online description: “Occurs when a task is waiting to acquire a NULL lock on the current key value, and an Insert Range lock between the current and previous key. A NULL lock on the key is an instant release lock.”)
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Added in SQL Server version:
Removed in SQL Server version:
Extended Events wait_type value:
The map_key value in sys.dm_xe_map_values is 15 in all versions through 2014 RTM. After 2014 RTM, you must check the DMV to get the latest value as some map_key values have changed in later builds.
Known occurrences in SQL Server (list number matches call stack list):
Abbreviated call stacks (list number matches known occurrences list):