Cache buffers chains&n…

Cache buffers chains latch

This latch is acquired whenever a block in the buffer cache isaccessed (pinned).Reducing contention for the cache buffer chainslatch will usually require reducing logical I/O rates by tuning andminimizing the I/O requirements of the SQL involved. High I/O ratescould be a sign of a hot block (meaning a block highlyaccessed).

当一个数据块被存取时，这个锁会自动获取。为了减少cache buffer chainslatch的争用，一般会通过调优，和最小化sql调用产生的I/O请求来减少逻辑I/Orates ；高I/O rates标志着热点块（意味着这个块非常高的存取）

Cache buffers LRU chain latch

The cache buffer lru chain latch is acquired in order to introducea new block into the buffer cache and when writing a buffer back todisk, specifically when trying to scan the LRU (least recentlyused) chain containing all the dirty blocks in the buffercache.
为了说明一个新的数据块要写到buffer cache中，及当把一个buffer cache 写回到disk，特别是在扫描LRUchain 中包含的所有buffer cache 中的脏数据块（dity block），时才去获得cache buffer lruchain latch 。