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Description:
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 UP (update) 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:
Pre-2005/2005
Removed in SQL Server version:
N/A
Extended Events wait_type value:
The map_key value in sys.dm_xe_map_values is 35 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.