Return-Path: Received: from newsfeed.cts.com (newsfeed.cts.com [209.68.248.164]) by naude.co.za (8.11.2/8.11.2) with SMTP id g78Hnl430680 for ; Thu, 8 Aug 2002 13:49:47 -0400 Received: from fatcity.UUCP (uucp@localhost) by newsfeed.cts.com (8.9.3/8.9.3) with UUCP id KAA30973; Thu, 8 Aug 2002 10:47:15 -0700 (PDT) Received: by fatcity.com (26-Feb-2001/v1.0g-b71/bab) via UUCP id 004AF718; Thu, 08 Aug 2002 10:36:05 -0800 Message-ID: Date: Thu, 08 Aug 2002 10:36:05 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: Rajesh.Rao@jpmchase.com Sender: root@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: Rajesh.Rao@jpmchase.com Subject: LMT and what is the Bitmap Header Size? Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0g, build 71; ListGuru (c) 1996-2001 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by naude.co.za id g78Hnl430680 I have been struggling to find the right answer to the question: What is the bitmap header size for a uniform extents LMT? 64K, 1 block, 2 blocks???? I find one note on Metalink (Note: 111666.1) that says its 64K . Mr.Jonathan Lewis says " A quirky little detail about bitmap sizes also came up recently on the Oracle-L mailing list. If you define a very small tablespace - in this context 'very small' means something between 5 blocks and '64K plus one extent' then Oracle will give you a bitmap of just one block - which still allows you to grow the file quite comfortably, of course." Then another example on Metalink (Note: 109630.1) which goes: SQL> create tablespace mult 2 datafile '/oracle2/OFA_base/u02/oradata/V816/mult1.dbf' size 100k, 3 '/oracle2/OFA_base/u02/oradata/V816/mult2.dbf' size 100k 4 extent management local uniform size 50K; Tablespace created. SQL> select tablespace_name,file_id,block_id,blocks 2 from dba_free_space 3 where tablespace_name='MULT' ; TABLESPACE_NAME FILE_ID BLOCK_ID BLOCKS ------------------------------ ---------- ---------- ---------- MULT 15 4 25 MULT 16 4 25 BLOCK_ID=4 : In an ordinary datafile, the first block where to store data is block 2. Therefore, two more blocks are reserved for the header bitmap of the locally managed datafile. BLOCKS=25 : The datafile has a size of 100K which equals 50 blocks in this database => There are only 25 blocks (local uniform size 50K)left for data starting at block n°4, then 22 blocks are unused. => Header bitmap = 2 blocks for each datafile Moi Confused. Whats the definite word on this? Should be something like if the datafile size is x, then its n, else its some other number. Thanks Raj -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: Rajesh.Rao@jpmchase.com 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: ListGuru@fatcity.com (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).