标签：oacle
本文为在某PUB提问后得到的版主回复
A shared pool has subpools (starting with 9i) and each subpool has sub-subpools or durations (starting with 10gR2 I think). It‘s easy to understand why there‘re subpools; each subpool is managed pretty much independently, with its own LRU list etc., and all subpools have the same functionality. But durations are different. Each one holds different types of objects. According to heapdump, as shown in Jonathan Lewis‘s "Oracle Core Essential Internals" p.184, dictionary cache is in duration 1, heap 0 (cursor head or parent cursor) in duration 2, SQLArea (heap 6) in duration 3.[note] Different types of objects have different characteristics. Within each type, objects have similar characteristics, such as size requirement, how long they stay in memory, etc. Oracle‘s work on shared pool durations is kind of like Linux kernel slab. A chunk of memory is allocated from a specific duration (slab) depending on what function you want to use this memory chunk for.
标签：oacle
原文地址：http://blog.csdn.net/ashic/article/details/43227627
