Performance Tuning - Question 034

Contention can occur on the cache buffer LRU chain latch on very busy systems because?

A . A latch must be obtained only when adding a buffer to one of the LRU lists.

B. A latch must be obtained when moving, adding, or removing a buffer from one of the LRU lists.

C . A latch must be obtained only when removing a buffer from one of the LRU lists.

D . A latch must be obtained only when moving or removing a buffer from one of the LRU lists.

Explanation:

Answer B: Any activity that affects the status of a block of data in the DB buffer cache requires obtaining a LRU latch. The cache buffer LRU chain latch is responsible for protecting the LRU list.