Oracle-L: Re: Tablespaces

From: <Jared.Still_at_radisys.com>
Date: Tue, 11 Mar 2003 14:05:22 -0800
Message-ID: <F001.00566F92.20030311140522@fatcity.com>

I've been in Windoze land too long. I forgot about sparse files.

Here's the info on a 2 gig tempfile:

14:2-rsysdevdb:dv01:jkstill-10 > du temp3.dbf 76 temp3.dbf
[ /u01/oradata/dv01 ]

14:2-rsysdevdb:dv01:jkstill-10 > ~/perl/hexdump temp3.dbf|head -20
00000000   00000000 00200000 00e80300 5d5c5b5a   ..... ......]\[Z
00000010   a0810000 00000000 00000000 00000000   ................
00000020   00000000 00000000 00000000 00000000   ................
00000030   00000000 00000000 00000000 00000000   ................
00000040   00000000 00000000 00000000 00000000   ................
00000050   00000000 00000000 00000000 00000000   ................
00000060   00000000 00000000 00000000 00000000   ................
00000070   00000000 00000000 00000000 00000000   ................
00000080   00000000 00000000 00000000 00000000   ................
00000090   00000000 00000000 00000000 00000000   ................
000000a0   00000000 00000000 00000000 00000000   ................
000000b0   00000000 00000000 00000000 00000000   ................
000000c0   00000000 00000000 00000000 00000000   ................
000000d0   00000000 00000000 00000000 00000000   ................
000000e0   00000000 00000000 00000000 00000000   ................
000000f0   00000000 00000000 00000000 00000000   ................
00000100   00000000 00000000 00000000 00000000   ................
00000110   00000000 00000000 00000000 00000000   ................
00000120   00000000 00000000 00000000 00000000   ................
00000130   00000000 00000000 00000000 00000000   ................

[ /u01/oradata/dv01 ]

14:2-rsysdevdb:dv01:jkstill-10 >

Sparse files are full of zeroes.

Jared

"Daniel W. Fink" <optimaldba_at_yahoo.com>
Sent by: root_at_fatcity.com
03/11/2003 12:28 PM
Please respond to ORACLE-L

        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        Re: Tablespaces - datafiles

When a regular datafile is created, Oracle writes 0s to the blocks. TEMPORARY files are created as 'sparse' files. Essentially, a header and footer are created, space is allocated in the file control structures, but nothing else is written. IIRC, this was introduced in Oracle8i, but not really documented.

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Daniel W. Fink
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Author: Daniel W. Fink
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