A couple of weeks ago we migrated our Oracle database from 9i to 10g and moved it to a faster, more powerful server. The migration went extremely well, especially considering these types of moves are usually planned out very carefully, well in advance.
We did end up having a few minor hiccups after the cutover – one related to a runaway query that had been tweaked in 9i but which 10g thought it could execute without the 9i tweak. Adding a query execution plan fixed that problem and we were running along smoothly. It is nice to have a DBA (database administrator) who seems to know what he’s doing – and the DBA-in-a-box tools that come with 10g made things much easier to track down.
We still were having problems with our CDAs (Content Display Application) after the database migration – with hardly any work being done on the database after it got its new home (and we segregated NetTracker to its own database and server). Our lead programmer was able to implement caching of the XSLTs (eXtensible Stylesheet Language Transformations) which take the XML and transform it into HTML which the browser can read. Each webpage has probably close to 100 XSLTs that are run on it to form it into one HTML document. We treat the XSLTs like templates, which are reused throughout our sites and are edited very rarely. Caching them made a lot of sense – and even with a 5 minute cache, we were able to decrease the load on the CDA servers by ten-fold and as well as decreasing our full-page load times from 6-10s down to 3-4s. I need to check on our monitoring to see how we’ve been doing at peak traffic times (typically around noon EDT for us), but this was a major improvement.
Our front end web server (MS IIS) was also replaced with Apache since we were seeing some inconsistencies with mod_jk running on the windoze box and talking to Apple OSX and RedHat in the JBOSS CDA cluster. Our next step will be to look at possibly adding more servers into the CDA cluster with a load balancer and another apache web server on the front end.
Overall a nice team effort.