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This wait type is when a thread is calling the Windows CryptImportKey function.
(Books Online description: N/A)
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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 422 in 2008 and 2008 R2, 470 in 2012, and 486 in 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.
If you see long waits for this wait type, have your infrastructure team investigate performance issues with servers that provide cryptographic services to the domain (for instance, the server for an Enterprise Key Management system).
Note that when a thread calls out to Windows, the thread changes from non-preemptive (SQL Server controls the thread) to preemptive (Windows controls the thread) mode. The thread’s state will be listed as RUNNING, as SQL Server doesn’t know what Windows is doing with the thread.
Known occurrences in SQL Server (list number matches call stack list):
- Importing a key (in this case, while initializing TDS while starting the instance)
- Importing an asymmetric key (in this case, to decrypt a column value)
- Importing a key (in this case, as part of compiling a certificate-signed stored procedure)
And other similar stacks.
Abbreviated call stacks (list number matches known occurrences list):