|
|
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. ------------------------------- Figure 6-11. This script will show the number of clones for buffers having at least one clone. It is simple to tell if there are clones because there will more than one buffer header with the same file number and block number. Figure 6-12. Some of the output of OSM clone script, clone.sql. Notice this figure shows only the last page (page 93), which means there are many buffers with clones, but none with more than six. Not only does its free buffer search algorithm favor replacing cloned buffers, but Oracle tries to limit the number of clones per buffer. Oracle wants the number of clones per buffer to not exceed the hidden instance parameter _db_bock_max_cr_dba, which has a default value of 6. However, if the cloning situation becomes intense, a buffer can easily have more than six clones. 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!