zoukankan      html  css  js  c++  java
  • free buffer waits等待事件

    Problem This will happen if there is no free buffer in the buffer cache for the session to read a new block into. All buffer gets have been suspended. This will frequently occur because DBWR is not writing out buffers fast enough. This could happen when a file was read-only and is now read-write. All the existing buffers associated with the read-only file need to be invalidated since they are not linked to lock elements (needed when mounted parallel (shared)). So cache buffers are not assigned to data block addresses until the invalidation is finished. The session moved some dirty buffers to the dirty queue and now this dirty queue is full. The dirty queue needs to be written to the file system first. The session will wait on this event and try again to find a free buffer This also happens after inspecting free buffer inspected buffers. If no free buffer is found, Oracle waits for one second, and then tries to get the buffer again (depends on the context). Small buffer cache can cause high free buffer waits when large amount of PIOs and LIOs are taking place. Solution Improve DBWR Throughput  
  • 相关阅读:
    关于代码风格
    python笔记-glob模块
    python笔记-mysql安装与配置
    python笔记-shutil模块
    python笔记-os模块
    python笔记-内存分析
    python笔记-装饰器
    python笔记-正则表达式
    python笔记-迭代器-生成器-对象生成式
    python笔记-模块和包
  • 原文地址:https://www.cnblogs.com/macleanoracle/p/2967903.html
Copyright © 2011-2022 走看看