Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> Re: Compressing partitions

Re: Compressing partitions

From: Tanel Põder <>
Date: Mon, 4 Jul 2005 13:37:06 +0100
Message-ID: <00ff01c58095$16e78040$0301a8c0@porgand>


If you are talking about historical data, which you won't be modifying later on, I don't see any real downsides with compression, but with frequently modified OLTP data, yes.

Performancewise, you might want to order your data pysically according your main index used in range scans on table as well, that way range scans using this index will me more efficient as table rows are physically clustered in the order of your index (if performance isn't an issue, then don't bother).

If you want to do physical row ordering, then that's one way to go:

create table temp nologging compress as select * from your_table partition p1 order by col1,col2,col3;

create index i1 on temp(col1,col2,col3) nosort nologging compress x; create other indexes... w compress option

alter indexes back to logging (if you want to, for maintenance reasons)

alter table your_table exchange partition p1 with table temp including indexes without validation;

alter table your_table modify partition p1 logging;

Also, a very interesting article regarding efficient partition exchanging is Tanel.

  We have several large 2-4 gig partitions on a 5 year basis. After a month or two, changes should be almost non-existent.

  They also have partitioned indexes. Just makes things easier when we roll off the oldest partition, etc.

  Is there a downside to compression?

  It's sounds like it's supposed to be more stable now, handling tables and indexes.

  While I've not found much, it seems like we could expect the 2-4 gig to maybe be 200-400 meg??? Even if 25-50% would not be bad given some of it is 5 years history.

  We are at

  Michael Kline
  Database Administration
  SunTrust Technology Center
  1030 Wilmer Avenue
  Richmond, Virginia 23227
  Outside 804.261.9446
  STNet 643.9446

  Cell 804.744.1545    

  The information transmitted is intended solely for the individual or entity to which it is addressed and may contain confidential and/or privileged material. Any review, retransmission, dissemination or other use of or taking action in reliance upon this information by persons or entities other than the intended recipient is prohibited. If you have received this email in error please contact the sender and delete the material from any computer.    

  Seeing Beyond Money is a service mark of SunTrust Banks, Inc.   [ST:XCL]

Received on Mon Jul 04 2005 - 07:39:06 CDT

Original text of this message