Update on Blackboard Performance Issues

by Terri Winters

CIS made several changes to the Blackboard environment early Wednesday morning, November 9th, that dramatically improved Bb responsiveness. This is in light of the fact that use of Bb on 11/9/05 was at the highest level we’ve seen since early October when we began gathering statistics, and the fact that we returned only 4 of 7 Bb application servers into the production environment. We are currently (11/10-11/14/05) working with Blackboard engineers to complete a full performance audit of our system. We are not yet able to say exactly what has caused our problems definitively (we suspect it has been a series of issues and not just one thing), but feel confident that we are getting very close and made significant progress to date.

The changes made Wednesday morning, November 11 had to do with managing connections to Bb from the single sign on application. The following is an explanation of the technical details of the problem we addressed.

A pool of connections should be available for use when one enters a username and password to request a connection to Bb. We discovered that a pool of connections was not being created, but that a single connection would be initiated and closed with each connection request. This behavior is very inefficient and caused a backlog of connections to be processed which manifested as slow response time.

As the response time grew worse, naturally people clicked the “OK” button repeatedly to process their request. Each click engendered another request for a connection adding again to the backlog. In addition, the number of people accessing Bb grew 40% on Monday from what we had seen previously. This increased load coupled with the pool connection problem combined to cause the extremely bad performance for Bb on Monday, November 7 and Tuesday, November 8. Our Bb developer, Dmitry Sadykov, rewrote parts of our single sign on application to efficiently using a pool of connections. Implementing that revised program in our Bb production environment was the change we made.

We appreciate that many in the community continue to use Bb despite the issues that we’ve had and the intermittent poor performance. We understand that such patience is not infinite, nor should it be. We hope to report soon the final, definitive answer to what exactly those issues have been that have caused the unacceptable performance of Bb, and what we’ve done to correct them. CIS will also be holding an open forum in December (check myunh.unh.edu for more information) to enable students, faculty, and staff to have a chance to express their concerns about Blackboard.

-Published in December 2005