技术人生系列 · 我和数据中心的故事（第四期）——Orac 11203必须要调整的重要参数

spider0283 · 发表于 2016-1-28 09:11

感覺是轉圈了，這麼高的log file sync並且每秒transaction那麼低，應該直接看存儲狀態

jieyancai · 发表于 2016-1-28 10:11

本帖最后由 jieyancai 于 2016-1-28 10:13 编辑

bluemoon0083 发表于 2016-1-28 02:31
oracle表示本来是个awesome的特性，谁知玩脱了

https://blogs.oracle.com/sistare/entry/high_resol ...

http://www.anbob.com/archives/2077.html
Post/wait, traditional method for posting completion of writes to redo log
LGWR explicitly posts all processes waiting for the commit to complete.
The advantage of the post/wait method is that sessions should find out almost immediately when the redo has been flushed to disk.
Polling, a new method where the foreground process checks if the LGWR has completed the write.
Foreground processes sleep and poll to see if the commit is complete. The advantage of this new method is to free LGWR from having to inform many processes waiting on commit to complete thereby freeing high CPU usage by the LGWR.If post/wait is selected and the foreground processes fail to receive a post from LGWR, an incident is recorded.diagnostic traces are performed, and polling is used instead of post/wait.