RE: Partitioning Question (1 of several)
- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxxxxx>
- To: <oracle-l@xxxxxxxxxxxxx>
- Date: Mon, 22 Mar 2004 14:24:48 -0500
Well, I'm certainly not the partitioning expert, but I think what it's saying
is that if the index is partitioned differently from the table, then for index
access paths, they are eligible for partition pruning, even if said pruning is
not compatible with the table's partition scheme. This makes sense, since the
index is global and partitioned, partition pruning can happen at index access
time, then whatever index access operation is dictated, then the requisite
table access by rowid to get any required data from the table. Since it's a
global index, the rowids in the index entries from the index partition that was
utilized, may point to any table rows in any table partition.
-Mark
-----Original Message-----
From: david wendelken [mailto:davewendelken@xxxxxxxxxxxxx]
Sent: Monday, March 22, 2004 1:36 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: Partitioning Question (1 of several)
"Partition pruning dramatically reduces the amount of data retrieved from disk
and shortens the use of processing time, improving query performance and
resource utilization. If you partition the index and table on different columns
(with a global, partitioned index), partition pruning also eliminates index
partitions even when the partitions of the underlying table cannot be
eliminated."
I not positive I understand the second sentence. Could someone give an example?
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