I used to believe this option was something almost absolute: it should be enabled as best practice. I was in some way happy when all my demos for SQL Server 2022 started to fail, and I discovered it was because this option was enabled by default. This weekend I attended a technical session which caught … Read more
The previous installment of this series examined aggregate subquery removal and subquery coalescing, describing the latter as similar in some ways to an inverse for “Or Expansion” and “Join Factorization”. In this instalment, it’s time to take a closer look at Or Expansion and we’ll move on to Join Factorization in the next instalment.… Read more
Indexes are expensive to maintain so we want to get the greatest benefit we can from them and make sure that Oracle uses them whenever it’s appropriate. Sometimes, though, the optimizer seems to ignore indexes that we think would be very effective and when this happens it’s often because the statistics that Oracle has gathered do not reflect the quality… Read more
Occasionally, when you install identical databases on two different SQL Server instances, they will behave in surprisingly different ways. Why? Most likely, it is down to different configuration settings. There are around seventy of these settings and the DBA needs to be aware of the effect that many of them have. Brad McGehee explains them all in enough detail to help with most common configuration problems, and suggests some best practices.… Read more
Why don't we emphasize the huge advantages of parameterized queries over ad-hoc queries in SQL Server? There is a severe impact on resources and performance from repeatedly using similar ad-hoc queries, instead of reusing the existing query plans. David Berry shows how you can measure this impact, and springs a surprise or two in the process
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