what is SQL server latch? does is it slow down the performance of sql server

Question

hi
what is sql server latch, does it slow down the performance of sql server?
i am attaching screenshot from one sql server and in this server the latch is high, does it affect the performance of server. how latch became high?

Answer 1

Hi AntonyMaxwin-4065,

Latches are lightweight synchronization primitives that are used by the SQL Server engine to guarantee consistency of in-memory structures including: index, data pages, and internal structures, such as non-leaf pages in a B-Tree. Latch contention occurs when multiple threads concurrently attempt to acquire incompatible latches to the same in-memory structure. Please refer to this doc to diagnose and resolve latch contention, which might be helpful.
Best Regards,
Amelia

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Answer 2

Please see:
https://blog.sqlauthority.com/2014/03/16/sql-server-what-is-the-difference-between-latches-and-locks/#:~:text=%E2%80%9CWhat%20is%20the%20difference%20between%20latches%20and%20locks%3F%E2%80%9D&text=Latches%20are%20internal%20to%20the,to%20provide%20logical%20transactional%20consistency.