How to Read an Execution Plan: Databases for Developers: Performance #1

An execution plan is one of the core tools for analyzing SQL performance.

But how do you get one? And how do you make sense of it once you've got one?

Watch this video to learn how to get and understand plans using Oracle SQL Developer.

For more on execution plans, read:

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The Magic of SQL with Chris Saxon

Copyright © 2018 Oracle and/or its affiliates. Oracle is a registered trademark of Oracle and/or its affiliates. All rights reserved. Other names may be registered trademarks of their respective owners. Oracle disclaims any warranties or representations as to the accuracy or completeness of this recording, demonstration, and/or written materials (the “Materials”). The Materials are provided “as is” without any warranty of any kind, either express or implied, including without limitation warranties or merchantability, fitness for a particular purpose, and non-infringement.

[therasammaldaniel]

You're the best SQL teacher we have ever seen. The way you explain with examples is easy for a layman too to understand. Thank you very much for everything you offered to us so far. You should be global reach.

[macpaz]

by far the best video on query performance on youtube. thank you!

[Symmetryful]

I just wanted you to know that you’re a natural teacher. And that is really rare!

[Thedirasa]

He is making this video from his media room. Appreciate your contribution to the world.

[kopaczp]

Perfect! Very easy and joyful explanation of (usually) database subjects! Thanks!

[mostafayahia]

Big fan of your work from Egypt.. Thank so much for your effort

[mustaphachatbi]

found your channel recently, did not watch your videos yet but seems interesting and just wanted to encourage you and thank you (y)

[lancemartin]

In the first 8 seconds of your video, I decided to sub. Nice job bro.

[sanketmandlik]

Working on PLSQL since 3 yrs. This is much needed skill. Eagerly waiting for next video. Also I didn't understand that subquery execution part.

[nileshsahastrabuddhe]

Thanks sir 🙏🙏🙏 really good explanation

[MeerAthil]

Good explanation, easy to understand. Please make videos on oracle locks and how to fix it

[jinan.es.]

You're amazing... I mean you really are amazing!

[Kivencito]

I loved the video! thank you SO much! :)

[payalmadhavi]

Gr8 job!expecting more vedios on db security.

[nhatquang]

can this be applied for Sql server too? anw, thanks for very comprehensive video.

[jorgebedoyarpo]

Thank you very videos are very useful to me.... I want to ask yo something... I am interested in watching your videos about performance, especially about execution plans....I see that you have some videos about that theme.... In what order do you suggest I see them?

[rohitpuranikratlami]

Hello Sir,
I have one doubt please guide me:
In the video at 6:25, number of rows from cuddly toys it's showing 5 in LAST_OUTPUT_ROWS column, don't it should be 3. Later then 9 rows from pen make that to 7.Got confused here so I think there is some logic which I am missing so wanted to know whats the logic to arrive to those numbers.

[sirknumbskull]

Your autotrace looks simple. My is full if index and access prediction. Is there a way to make it more simple?

[prashanthr]

hi, May I know how to find best join order and index for a huge query with a huge explain plan..

[personalchaoyu]

So first question first, what are behind that tinny door ?