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When one talks about "pinning" in indexes, what exactly is this? Is there some other word/term I can search for, as google has not provided any solutions.

It is part of a test question, where students were asked to define and describe pinning in relation to indexes.

Does anyone have an idea?

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closed as off topic by mgorven, RobM, rnxrx, Michael Hampton, Scott Pack Oct 2 '12 at 18:28

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1 Answer

"pinning" in Oracle parlance basically means "ensure that this is always kept in memory".

It is frequently used for hot indexes that see a lot of queries against them, but might ordinarily age out of Oracle's cache (and thus have to be re-read from the disk). By pinning the index in memory the index scan will theoretically never require a disk access. If the index is large and the cache cycles frequently this could be a substantial performance improvement over frequently refreshing the cache.

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Many thanks for your reply! Do you think you could link some sort of explanation as I need to read about it in detail. Or is there possibly another word for it? –  Database User Jun 1 '12 at 19:04
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