Category: Oracle

July 30

Hmmm, still busy to setup a baseline environment to do some serious XMLDB performance / architecture testing. I am almost now on the point were I really can start, but until now I ran into a lot of issues… It also told me that the mediawiki dumpfile is good set of XML data to work with. A lot of variance is build in. I hope I won’t encounter too muchmore issues though…

July 29
July 20

While setting up a baseline for my XMLDB performance tests, I noticed that my “count(*)” on a Binary XML table (using Securefile LOB storage) called “WIKI_STAGE” took an awful long time. So long, that I even had to kill the SQL*Plus session, that was executing the “count(*)”. I started wondering. Why did it take so long to come up with the result?

In the end, due to good advice from Jonathan Lewis, I came up with a solution (although probably unsupported) and a better understanding off the mechanics involved. Also, as a side effect, it triggered a really good discussion on the “Oracle-L” freelist, regarding “counting”.

But lets start from the beginning…