Mark, These are primarily data buffer / 130 type waits and the sql causing most of them is cursor type junk that needs to be rewritten. I added freelists to a few objects yesterday and saw the numbers decrease slightly, but I believe everything that is left falls exactly into this category. sigh .. further confirmation that this is going to take a long, long time ... Robyn On Tue, 24 Aug 2004 11:29:26 -0400, Bobak, Mark <mark.bobak@xxxxxxxxxxxxxxx> wrote: > In addition to Cary's excellent advice, here's a bit of specific = > knowledge > that may help you. When you encounter buffer busy waits, there are a = > few > things to consider. What type of block is seeing the waits? If it's a > segment header, then looking to increase free lists is probably a good > idea. If it's data blocks (table or index), then what's the P3 value? > If it's 130, that means that the buffer is busy cause data is being read > into it (due to one of the db file sequential/scattered reads). These > types of buffer busy waits are secondary to heavy physical I/O that's > colliding on blocks. (This can easily be seen/simulated by doing > concurrent full table scans on "large" tables, for sufficiently large > values of "large", or even due to concurrent fast full index scans or > grossly inefficient index full or range scans.) So, if you see P3 > set to 130 for data blocks, you want to focus on your inefficient SQL > that's causing db file sequential/scattered reads. When you get those > under control, that entire class of buffer busy waits ought to = > disappear. > There are other cases of buffer busy waits, but in my experience=20 > they're less common, and I won't write more on them unless you reply = > back > that you're seeing things that don't fit either the segment header case=20 > or the data block w/ P3 set to 130 case. > > You definitely want to follow Cary's advice as to the overall approach, > but the above maybe helpful in diagnosing and dealing w/ buffer busy > waits as you encounter them. > > Hope that helps, > > -Mark ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------