Rebuild Index: how long does it take?

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Hi,

On 11.2.0.4 on AIX

Can we estimate how much time is necessary to rebuild an index when we know number of rows in the table and number of keys?

Should we have another information?

Thanks and regards.

[ErmanArslansOracleBlog]

I suggest you to read Richard Foote's notes on Index Internals
For instance; the following one ->

https://richardfoote.files.wordpress.com/2007/12/index-internals-rebuilding-the-truth.pdf

You can't directly estimate that time.. It depends on your environment and how you rebuild those indexes.. It depends on your Full table scan performance, your sort performance etc.. But you can test it on a TEST instance (running on a similar platform in terms of computational and storage resources) and get an idea about it.

However; there are things that you can do for increasing the speed of such a rebuild operation.. (you can rebuild an index in parallel mode for instance..)

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Thank you.