Category: RDBMS
September 23

Grid 2.0 – The Next Step for Real Application Clusters

Let me be clear, I am not a RAC guy, but while using the schedule builder this year, one presentation had a definite hint to the upcoming 11gR2 release. Bob Thorne, Director of Product Management (Oracle) gave an insight on Monday, into the new Grid 2.0, via his presentation called “Oracle Grid Computing 2.0: A Preview“:

Grid 2.0 will include a new grid infrastructure that dramatically extends the benefits of Oracle Grid Computing. This session covers this new infrastructure, which will greatly simplify the management of a cluster, propelling grid computing to a mainstream architecture. New quality-of-service capabilities will make meeting performance objectives in a shared infrastructure environment easy and automatic. The session also introduces exciting new storage management features that extend the benefits of Automatic Storage Management to all files.

His presentation gave insight in the upcoming new RAC infrastructure which had the following characteristics (as far as I can remember):

Read the postGrid 2.0 – The Next Step for Real Application Clusters
July 20

XMLDB Performance: The Side Effects of a Simple “count(*)”

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…

Read the postXMLDB Performance: The Side Effects of a Simple “count(*)”
July 11

HOWTO: Load Really Big XML Files

Sometimes you will want to load data from huge XML files into the database. So how do you achieve this?

There are more then one ways to achieve this, but most of the time a “SAX parser” is used. The term on Wikipedia for SAX is:

A Simple API for XML (SAX) is a serial access parser API for XML. SAX provides a mechanism for reading data from an XML document. It is a popular alternative to the Document Object Model (DOM).

The disadvantage sometimes of using DOM is that it uses to much resources in the sense of CPU and memory and for really huge files this method simply will not work in terms of performance. Parsing an XML document with DOM acquires the whole document to be loaded into memory before processing can be started. Via SAX only a small memory footprint is needed.

Read the postHOWTO: Load Really Big XML Files