Monthly Archives: May 2013

In Oracle when you compare a character and a number in a SQL WHERE clause Oracle converts the character value to a number rather than the other way around.  I built a simple example to help me understand how this … Continue reading →

Hopefully this isn’t too redundant.  Saw another performance issue today caused by a type mismatch between a bind variable and the column it was compared to in a SQL statement.  I saw this in some real code and then built … Continue reading →

I was working on some disk performance problems and came across a simple way to test the latency or delay built into the networks that connect my database servers to their disk storage.  All I have to do is read … Continue reading →

I’ve seen some very good information posted in this feed which combines blog postings from many different Oracle performance experts who are part of what is called the “Oak Table” http://www.oaktable.net/feed/blog-rss.xml (NO LONGER EXISTS) I’ve been using Internet Explorer to … Continue reading →

In my forum discussion about free buffer waits I came across a term that I didn’t understand: “inode lock contention”.  I’m pretty sure I had seen this same term years ago on one of Steve Adams’ pages on IO.  But, … Continue reading →

I just read this post about a new patch that will allow you to affect the way the optimizer calculates clustering factor and hence how likely it is to choose a particular index for a query plan. http://richardfoote.wordpress.com/2013/05/08/important-clustering-factor-calculation-improvement-fix-you/ Pretty cool.  … Continue reading →

This is a good web site with Oracle internals information: http://www.ixora.com.au/notes/ (NO LONGER EXISTS) I’ve benefited from this one for years. – Bobby

In my previous post I explained that setting db_writer_processes=1, dbwr_io_slaves=32 made a 2-3 times reduction in run time of my test of 15 concurrent updates. Further testing has shown that an even greater improvement – really 10 times – can … Continue reading →