Category: Oracle
July 15

Setting Up an XMLDB Performance “Baseline” Environment

I just read Thomas Kyte’ s blog post “Read This“, which is dealing with the content of the blog post of Cary Millsap. As Tom phrased it:

I liked what Cary Millsap just said:

I don’t mean “show and tell,” where someone claims he has improved performance at hundreds of customer sites by hundreds of percentage points [sic], so therefore he’s an expert.

I mean show your work, which means documenting a relevant baseline measurement, conducting a controlled experiment, documenting a second relevant measurement, and then showing your results openly and transparently so that your reader can follow along and even reproduce your test if he wants to.

This is more or less funny, because I read Cary’s post, be apparently I didn’t read it… I can really relate to it now.

I am in the middle of setting up a XMLDB test environment to test, among others, load times while using different kinds off XMLType storage based upon CLOB, Object Relational and Binary XML (using Basicfile / Securefile options). And although I am working on a VMware environment, I noticed that it isn’t that easy to setup a “controlled experiment“. What makes it harder is, that I am using the Mediawiki XML English dumpfile, that contains roundabout 7 million records (17 Gb of ASCII data). This makes it more interesting, and the effects more clearer, but it also takes much more time to do stuff.

Read the postSetting Up an XMLDB Performance “Baseline” Environment
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
July 8

HOWTO: Create a Native Database Web Service

I noticed that when I wanted to do some tests with the 11g Native Database Web Service (again), NDWS for short, that I had to gather the information from all over the place on my site. Which was not so very handy. So here a short intro how to set it up, configure and deploy it, also based on the OTN XMLDB Forum example from Mark Drake.

Overview

In short you will have to do the following steps:

  1. Install Oracle XMLDB
  2. Enable the Protocol Server for HTTP access
  3. Enable the orawsv entry points in xdbconfig.xml
  4. Create an example to test the NDWS service
  5. Test the NDWS service by calling the WSDL entry point
  6. Troubleshooting

Sounds very complex, doesn’t it? But be assured, it isn’t at all. As pointed out, most of it is described in posts on this site.

Read the postHOWTO: Create a Native Database Web Service