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LATCH_DT

Short Description

Occurs when waiting for a DT (destroy) latch. This does not include buffer latches or transaction mark latches.

Detailed Description​

Latches are lightweight, fast methods of managing concurrency on a specific resource. This group of latches are seen in management of pages that have already been read into memory.

Books online says "Occurs when waiting for a DT (destroy) 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".

How to reduce this wait​

There is a great article in sqlskills.com under the LATCH_EX page which gives a breakdown of the steps needed to identify the latch which you are waiting on - as although the wait time is shown, it does not identify the specific latch being contended for.

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