Re: Partition exchange

From: Landrum Darrell <>
Date: Fri, 14 Mar 2008 20:40:59 -0500
Message-Id: <>

"Exchange partition never moves the data"?

   If you exchange partition from a partitioned table in one tablespace to a table in a different tablespace, the data has to be moved and that would create reads on the source table.

Darrell Landrum

On Mar 14, 2008, at 8:01 PM, Tim Gorman <> wrote:

> This is not true. Exchange partition *never* moves data in the
> table -- for this or any other reason. The "db file scattered read"
> wait-event is a read, not a write, so something is being scanned for
> some reason...
> Darrell Landrum wrote:
>> Hey Ken,
>> When doing the partition exchange to a different tablespace, all of
>> the data has to be moved. Data dictionary updates "only" would
>> only apply if keeping the segments in the same tablespace.
>> Regards,
>> Darrell
>> On Mar 12, 2008, at 7:35 PM, Ken Naim wrote:
>>> I am in the process of moving the partitions of a table from ASSM
>>> to a non-assm tablespace using the partition exchange method
>>> (create non partitioned table, indexes, constraints etc.). When I
>>> do the alter table exchange partition including indexes without
>>> validation command it runs for hours, doing a full table scan on
>>> all the partitions of the partitioned table which takes many
>>> hours. I understood that just the data dictionary is updated, and
>>> it should take a few seconds. Primary Wait event is db file
>>> scattered read. Can anyone shed some light on this phenomenon. DB
>>> version is and is running on Solaris 10.
>>> Thanks,
>>> Ken
> --

Received on Fri Mar 14 2008 - 20:40:59 CDT

Original text of this message