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ppad001 18 posts Joined 06/11
18 Jul 2014
Impact of using a compressed column in any join or predicate clause in a query

Hi All,
I would like to know If there would be any impact of I/O if we perform any join operations or filter operations on the compressed column considering compression property is majorly a space saving technique.
Hope I made myself clear.

krishaneesh 140 posts Joined 04/13
18 Jul 2014

IO would reduce due to MVC on any table. Even in a join and when reading from the table and writing into spool the read part would be less due to MVC.

Ashoktera 12 posts Joined 03/14
19 Jul 2014

In my understanding, MVC is not only to decrease the footprint of data on disk but improve access of the data also.  compressed table would relatively need less spool and so less I/O thus need less CPU too to process it.
So MVC helps in using all resources efficeiently.


ppad001 18 posts Joined 06/11
20 Jul 2014

Thanks all for clearing the doubt, henceforth i will keep that in mind :)

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