Query Tuning 101: How to Compare Execution Plans

When you're tuning SQL query there's two important questions to keep in mind:

* Have my changes made any difference?
* If they have, is performance better or worse?

In this video we'll look at how you can use SQL Developer to compare execution plans. This will enable you to differences between them and determine which plan performs better.

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The Magic of SQL with Chris Saxon

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[sanjayessarani]

Hi, Your videos are great and very well organized.

[learner]

Hello Sir
Your videos are really helpful and easy to understand

I followed the steps you've mentioned and I didn't get the consistent gets when I compare the autotrace of 2 queries (One is using a hint and the other one is without hint). I wanted to check which one performed well. How should I approach it ?

[karolylaszlo]

Hi, I watched and found really-really useful. I have only one question: How can I open the statistics window of the execution plan(s)? Unfortunately, I do not have the two small black narrow at the status line below the executions plans…. What shall I do?

[jorgebiltris]

Nice Video, but a question concerning the consistent gets mentioned after running the second autotrace. By comparison the second query is better. But when you now re-run the 1st autotrace these figures improve massively. I guess through caching/buffering. Is there a way to establish a baseline? I want to be able to compare without the buffered blocks. BR.