Cheaters Never Win, Even in TPC Benchmarks

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In a sense, the benchmark disclosures imply one of the fundamental lessons that most enterprise DBAs know by heart. That is, you should know the needs of your database workload intimately.   When this is the case, you can immediately tell whether a given configuration tweak, such as –T834, can help your application or not. 

If, on the other hand, you’re the sort of DBA who sees a performance tip and applies it without a full testing process, you’re doing it wrong!  I can’t tell you how many times I’ve spoken at conferences and gotten a question that goes like this “I read a blog post/magazine article/conference talk that recommended I enable XYZ. I gave it a try on one of my slow production servers.  It didn’t make performance any better or made things worse. Why is that?” There’s so much wrong with this sort of question, but it’s indicative of a very prevalent mindset among enterprise DBA:

The DBA didn’t have quantitative metrics of performance before and after the change. How can s/he every really know whether performance is better or not?

The DBA saw a tip for a specific workload and first didn’t verify or test whether it’d help with their specific workload.

The DBA didn’t have a rollback or undo process to recover in case of a very bad result from the change.

The DBA is violating the first rule of DBA-ness “You must protect the data as the main asset of the organization”.  Changes should be managed and scheduled, not rolled out haphazardly.

Having said all of that, if you are the sort of DBA who rigorously monitors and controls change within your databases, you can take a look at the TPC benchmark disclaimers to see if there’s a new tip or trick that you haven’t tested yet to see if they’ll help performance.

So, what about you? Have you ever enabled a trace flag or switch without enough testing?  How did you resolve that situation? On the other hand, have you rolled out a trace flag or switch that really improved performance? How did you find out about the tweak?  What was your process for rolling it out into production?

I’d love to hear back from you. Enjoy!


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