Time bomb coding
I come accross a great artical by David Poole on SQLServercentral about Time Bomb Coding
Well worth the read
At some point in your career you will be asked to get involved in diagnosing performance problems with a database application. Sometimes the diagnosis is simple but in other cases the causes of poor performance are subtle. From my own experience I have noticed that subtle performance bugbears conform to a pattern and I refer to this pattern as “Time Bomb Coding”. The pattern I am referring to has the following properties
- The system is well established
- There has been no significant alterations to the system for some considerable time
- Statistics and indexes are kept up-to-date
- Execution plans appear reasonable at first glance
- The database design appears to be simple and clean
- Traffic has not changed much over time
Despite this the system performance has been steadily degrading!
If this seems familiar to you then you are probably a victim of time bomb coding. In this article I should like to give a few of the many examples of this phenomenon I have come across.