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Re: select partition table with non partition key condition [message #462727 is a reply to message #462718] |
Sat, 26 June 2010 03:01 ![Go to previous message Go to previous message](/forum/theme/orafaq/images/up.png) ![Go to next message Go to next message](/forum/theme/orafaq/images/down.png) |
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Michel Cadot
Messages: 68678 Registered: March 2007 Location: Nanterre, France, http://...
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It's more an OS question than an Oracle one. Oracle does not care about real physical implementation, its physical level is the file, its logical level (on which execution plan is built) is the partition.
So if you want to know how it does it on your hard disk then use iostat.
Note that "at the same time" is only relevant if the query is executed in parallel which is not the default mode.
Regards
Michel
[Updated on: Sat, 26 June 2010 03:02] Report message to a moderator
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Re: select partition table with non partition key condition [message #462748 is a reply to message #462738] |
Sat, 26 June 2010 09:20 ![Go to previous message Go to previous message](/forum/theme/orafaq/images/up.png) |
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Michel Cadot
Messages: 68678 Registered: March 2007 Location: Nanterre, France, http://...
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No, it means Oracle chooses the way it wants to access the partition, assuming a serialized plan, 1 to 6, or 1 then 2 then 6 then..., or 6 to 1, or odd then even, or... You can make no assumption on the order it will take. The only you can know is that if you parallelize then Oracle will take care of the partition tablespaces to choose an optimal parallelization.
Regards
Michel
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