RE: Questions re redo log files

From: James Bullard <jbullard_at_onvia.com>
Date: Fri, 19 May 2000 12:53:25 -0700
Message-Id: <10502.106138@fatcity.com>

Redo buffers are written to the redo log files. Each buffer in the log buffer is the equivalent of one os block. There isn't a parameter which sizes your redo blocks, only the data blocks. Thus, why you need to specify 512.

Comments, corrections are welcome.

James
-----Original Message-----
From: Bill Wagman [mailto:wjwagman_at_ucdavis.edu] Sent: Friday, May 19, 2000 1:01 PM
To: Multiple recipients of list ORACLE-L Subject: Questions re redo log files

Hello,

I have been playing around with the dbv utility and have encountered several questions.

What are the ramifications of using the dbv utility to look at redo logs?

When I created the database I specified a database block size of 8192 in the init.ora file and used the following statement to create the database...

create database "isodtest"

     controlfile reuse
     maxinstances 1
     maxlogfiles  16
     maxdatafiles 30
     character set "US7ASCII"
     datafile


	'$ORACLE_LOCAL/data/isodtest/system01.dbf' size 100002K reuse

logfile


	'$ORACLE_LOCAL/data/isodtest/log01.dbf' size 10000K reuse,

	'$ORACLE_LOCAL/data/isodtest/log02.dbf' size 10000K reuse,

	'$ORACLE_LOCAL/data/isodtest/log03.dbf' size 10000K reuse;

yet when I run the dbv utility I must specify a blocksize of 512 to look at the redo logs.

Why is the block size of the redo log files 512? Do I need to worry about the fact that the blocksize is different from the rest of the files? Do I have any control over this at database creation time?

When I do analyze the redo logs the utility returns the following for each page...

DBVERIFY: Release 8.0.5.1.0 - Production on Fri May 19 11:42:33 2000

DBVERIFY - Verification starting : FILE = log01.dbf Page 1 is marked corrupt
***
Corrupt block relative dba: 0x00000001 file=0. blocknum=1. Bad header found during dbv:
Data in bad block - type:0. format:0. rdba:0x00000001 last change scn:0x0000.17b90186 seq:0x47 flg:0x65 consistancy value in tail 0x00000000
check value in block header: 0x800, calculated check value: 0x0 spare1:0x2f, spare2:0x59, spare2:0x0

Why does it return to me that there is an error on each page? This does not happen with any of the other files. Is this anything I need to worry about?

Thanks.

Bill Wagman
Univ. of California at Davis
Information Resources
wjwagman_at_ucdavis.edu
(530) 754-6208

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Author: Bill Wagman
  INET: wjwagman_at_ucdavis.edu

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Received on Fri May 19 2000 - 14:53:25 CDT