If you have good stats on the table just take the following and compare. actual size of object vs. (#rows * average row size )
If actual size is much larger than #rows * average row size, you have a lot of unused space in the table, this however does not tell you the high water mark. There are some various methods to determine this but I can't recall offhand, DBMS_SPACE package I think. I have never really been interested in my HWM, just if I have a lot of empty space which the above would show you. More importantly is know that and how well space at the block level is being used (%FREE $USED). I think the suggestion about rebuilding the table online by moving it to another tablespace and then back again will be your best bet if you are 24/7 shop. Better check the docs on this but I am pretty sure you can do while the db is up, just pick a time with low activity. Sorry I can be more helpful, really in the weeds here today. Thanks, Ethan -----Original Message----- Sent: Friday, January 18, 2002 9:41 AM To: Multiple recipients of list ORACLE-L Ethan The database is in production and users are accesing 24x7.What will be best approach to do? DO u have any scripts how to find HWM? Thanks -Seema >From: "Post, Ethan" <[EMAIL PROTECTED]> >Reply-To: [EMAIL PROTECTED] >To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> >Subject: RE: SPACE FREE HOW? >Date: Thu, 17 Jan 2002 14:25:37 -0800 > >Deleting records from a table does not free up space in the database. >Search for high water mark in the concepts manual and you should find an >explanation of how this works. The statement below only frees up space >above the high water mark on the table. > >You can... > >create table foo nologging as (select * from big_table); > >truncate table big_table; > >insert into big_table (select * from foo); > >drop table foo; > > >-Ethan > >-----Original Message----- >Sent: Thursday, January 17, 2002 3:27 PM >To: Multiple recipients of list ORACLE-L > > >ALTER TABLE table DEALLOCATE UNUSED KEEP integer; >the keep clause is optional. > >-sunil > >-----Original Message----- >Sent: Thursday, January 17, 2002 2:58 PM >To: Multiple recipients of list ORACLE-L > > >Hi >I deleted millions of rows from diffrent tables and I have not seen any >impact on database size.What I have to do to get that free space? >Is it necessary to shutdown the database? >Thx >-Seema > >-- >Please see the official ORACLE-L FAQ: http://www.orafaq.com >-- >Author: Post, Ethan > INET: [EMAIL PROTECTED] > >Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 >San Diego, California -- Public Internet access / Mailing Lists >-------------------------------------------------------------------- >To REMOVE yourself from this mailing list, send an E-Mail message >to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in >the message BODY, include a line containing: UNSUB ORACLE-L >(or the name of mailing list you want to be removed from). You may >also send the HELP command for other information (like subscribing). _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp. -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Seema Singh INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Post, Ethan INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
