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This wait type only exists so there is a LATCH_XX wait type for all possible latch modes. The Latches Whitepaper in the sidebar on the right has a description of all latch modes and their compatibility with other latch modes.

(Books Online description: “Occurs when waiting for a KP (keep) latch. This does not include buffer latches or transaction mark latches. A listing of LATCH_* waits is available in sys.dm_os_latch_stats. Note that sys.dm_os_latch_stats groups LATCH_NL, LATCH_SH, LATCH_UP, LATCH_EX, and LATCH_DT waits together.”)

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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 33 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.

Other information:

See the LATCH_EX wait type for more details.

Known occurrences in SQL Server (list number matches call stack list):

No known occurrences.

Abbreviated call stacks (list number matches known occurrences list):

No known occurrences.