@andrew gothard, @Ed Wagner etc.

I was not trying to imply that performance tests were unnecessary. On the contrary, I think that they are essential. What does slightly irritate me is the idea amongst some developers that it is impossible to do any development work without using production data. That was what was behind the 'really, really' phrase. Yes, I put a lot of effort to get performance right and the emphasis here is on accurate measurement, familiarity with the query plans, getting the indexing strategy right and having a properly normalised design. Where production data is particularly useful is in making sure that your database performs well with the plans generated with the volume and distribution of production data. If there are good practical reasons for restricting access to production data - and there is nothing new to this, there are established ways to get around this for performance tests without having a huge impact on development. There are other good reasons for having access production data during deployment such as testing your migration scripts. I'd be interested to hear how other developers have got around that where access to production data is restricted.