Oracle Tips

Do you use dbverify (dbv) against large datafiles to check for block corruption? Then chances are that you missed an 11gR1 New Feature: dbv can now divide one file into multiple parts and check them in parallel:

SQL> col name for a50
 SQL> select name,blocks from v$datafile;
NAME                               BLOCKS
 -------------------------------------------------- ----------
 /home/oracle/prima/system01.dbf             38400
 /home/oracle/prima/sysaux01.dbf             25600
 /home/oracle/prima/undotbs01.dbf            22912
 /home/oracle/prima/users01.dbf              1280

My demo system is on 11.2.0.3, but the feature is already there in 11gR1, as the doc page here shows. See the parameters start and end there.

[oracle@uhesse1 ~]$ dbv file=/home/oracle/prima/users01.dbf start=1 end=500

DBVERIFY: Release 11.2.0.3.0 - Production on Mon Aug 20 21:59:28 2012
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
DBVERIFY - Verification starting : FILE = /home/oracle/prima/users01.dbf
DBVERIFY - Verification complete

Total Pages Examined         : 500
Total Pages Processed (Data) : 11
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 0
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 136
Total Pages Processed (Seg)  : 0
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 353
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Total Pages Encrypted        : 0
Highest block SCN            : 212814 (0.212814)
[oracle@uhesse1 ~]$ dbv file=/home/oracle/prima/users01.dbf start=501 end=1280

DBVERIFY: Release 11.2.0.3.0 - Production on Mon Aug 20 22:10:16 2012
Copyright (c) 1982, 2011, Oracle and/or its affiliates.  All rights reserved.
DBVERIFY - Verification starting : FILE = /home/oracle/prima/users01.dbf
DBVERIFY - Verification complete

Granted, the file here is not large – but you should get the picture: I could have run the two dbv sessions from two different  terminal windows in parallel as well. I realized from a recent twitter thread that this 11g New Feature that I teach since years is probably widely unknown – did you know it?