Connection pooling crash course

Just spent the whole day tweaking our new uPortal installation and trying to get it to stay up reliably under load. It’s coming along, but not quite there yet. First lesson: Under any kind of load, you must, absolutely must, enable database connection pooling. That’s because if you don’t, it will open enough database connections to, let’s just say, really screw things up. Now, setting up connection pooling is not supposed to be that hard. But in our case, it was a huge pain. The default uPortal 2.4.3 configuration, includes a file uPortal.xml which is used to specify the connection pooling info to Tomcat. Great, I set it up with our connection parameters, and tried it out. Hmm, doesn’t seem to work. Look a little further.. Apparently in, I need to set the flag org.jasig.portal.RDBMServices.getDatasourceFromJndi to “true”, or it bypasses the whole connection pooling thing and just opens direct connections. I set it, and tried again. Major bombage. More poking around and I found this page describing the mechanics of Tomcat connection pooling. Apparently, the config file format (as well as the factory class name) changed from Tomcat 5.0.x to Tomcat 5.5.x. We’re running 5.5.x, and the uPortal distro’s config file in the 5.0.x format. So, I updated the config file. Plus as a good measure, I dropped a copy of the Oracle JDBC jar file into tomcat-root/common/lib. Not sure if it really needs to be there or not. But, once I jumped through all those hoops, the connection pooling finally seems to work.

Now, we’re dealing with memory issues causing slowness, as well as a couple lingering database issues with logins to the ‘myumbc’ user…

I hope I don’t have too many more days like this…

Update 1/12/2006: Well, it appears that the connection pooling breaks any ant targets that use the database: This includes pubchan as well as pubfragments, etc. This is kinda bogus, but rather than tweaking every time I want to publish a channel or fragment, it looks like I can just run these from the test tree (which uses the same set of database tables).


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