|
|
by Craig Shallahamer Get the book here |
|
|
Craig Shallahamer's Blog
The text below is an except from the book, Oracle Performance Firefighting, written by Craig Shallahamer of OraPub, Inc. Figures and tables are not included on this page, only their reference. To order the book in either print or PDF form, click here. ©2009, 2010 by Craig Shallahamer. This is copyrighted material. Please—Out of respect for those involved in the creation of the book and also for their familes, we ask you to respect the copyright both in intent and deed. Thank you. ------------------------------- So, when one of the top wait events is log file parallel write, remember that there are a number of Oracle-focused solutions available to you. Every Oracle DBA will eventually encounter the log file switch wait events. To summarize, the log writer background process is ready to switch writing from one online redo log group and begin writing to another, but it is prevented from doing so. As a result, all DML-related activity eventually comes to a screeching halt. There are two main ways this can occur, and each has its own related wait event. Figure 8-18 will be used to clarify both situations. Figure 8-18. Shown are the log writer (LGWR) and archive (ARCH) background processes, three online redo log groups, and a disk containing all the archived redo logs. The log writer background process is currently writing to online redo log group RLOG 100, and the archive background process is reading online redo log group RLOG 300 and writing it to the archived redo log disk. Please—Out of respect for those involved in the creation of the book and also for their familes, we ask you to respect the copyright both in intent and deed. Thank you. |
Know what's important before it's too late!
OraPub's
Performance Training
is like no other...
More Class Pics...
Get student testimonials!