Re: dbverify.exe

From: Roger Jackson <rjackson_at_wire.net.au>
Date: Thu, 8 Apr 1999 20:16:34 +1000
Message-ID: <7ehvqt$605$1@caley.wire.net.au>

Michael,

Here are some further details from Metalink

Article-ID:         <Note:35512.1>
Alias:              SUPTOOL:DBV
Circulation:        PUBLISHED (EXTERNAL)
Platform:           GENERIC  Generic issue
Subject:            DBVERIFY - Database file Verification Utility (7.3.2
onwards)
Modified-Date:      07-OCT-1998 10:33:11
Document-Type:      REFERENCE
Content-Type:       TEXT/PLAIN
Impact:             MEDIUM
Component:          DBVERIFY

DB Verify

DB Verify is a utility supplied with Oracle releases 7.3.2 onwards. It checks isolated data and index block internals for consistency and can be used to give some degree of confidence that a datafile is free from corruptions. It performs checks at a block level and so unlike 'ANALYZE TABLE .. VALIDATE STRUCTURE CASCADE' it does *NOT* perform any cross checks
between index and data blocks.

DBV can be used against data files from Oracle releases prior to 7.3 but it
must be executed from the ORACLE_HOME environment in which it is supplied.

Usage

Unix: dbv FILE [options]

  Windows NT:   DBVERFxx FILE [options]         (xx is the version)
                                                (Eg: DBVERF80 for Oracle

8.0)

Options:

        Keyword   Description        (Default)
        ----------------------------------------------
        FILE               File to Verify     (NONE)
        START           Start Block        (First Block of File)
        END               End Block          (Last Block of File)
        BLOCKSIZE    Logical Block Size (2048)
        LOGFILE        Output Log         (NONE)
        FEEDBACK    Display Progress   (0)

Usage Notes

This utility can ONLY be used against DATA files. It CANNOT be used to verify redo log files nor control files.
Datafiles are opened read-only. Hence DB Verify CAN be used against open database files.
In 7.3 (on Unix) you cannot directly reference a raw device as DBV expects a filename extension. The workaround is to create a symbolic link to the raw device - the link name MUST have an extension.

        Eg: ln -s /dev/rdsk/mydevice /tmp/mydevice.dbf
            Now use DBV against /tmp/mydevice.dbf

  4. For RAW devices you should use the START and END parameters
     to avoid running off the end of the Oracle file space.
     Use: START=1 END=<num blocks -1>
     If you get the END value too high DBV can report the last
     page/s of the file as corrupt as these are beyond the
     end of the Oracle portion of the raw device.

Example Results:

        DBVERIFY - Verification starting : FILE = users01.dbf
        kdbchk: a row ends in the middle of another
                tab=0 slot=1 begin=0x7a0 len=0x14
        Page 3 failed with check code 5
        Page 10 is marked software corrupt
        Page 12 is marked software corrupt

        DBVERIFY - Verification complete

        Total Pages Examined         : 512
        Total Pages Processed (Data) : 1
        Total Pages Failing   (Data) : 1
        Total Pages Processed (Index): 0
        Total Pages Failing   (Index): 0
        Total Pages Empty            : 507
        Total Pages Marked Corrupt   : 2
        Total Pages Influx           : 0

If the utility reports any pages to be 'Marked Corrupt' or 'Failing' then re-run the command to see if the problem is transient or not. If there are still corruptions reported then contact your local support centre for advice.

Notes:

Failing blocks are not dumped symbolically. Only the error is reported.
The Page number is the database block number within the file.
'marked software corrupt' actually means the block wrapper is incorrect.

References:
DBVERIFY START and END parameters <PrSol:2076746.6>

Michael Reeves wrote in message <7ed83h$85q$1_at_oak.prod.itd.earthlink.net>...
>How do I interpret the *.txt file created by running the dbverify.exe tool
>provided by Oracle. I run this tool after I have backed up the datafiles,
>before sending them to tape. I am unsure what "pages" mean when referring
to
>a datafile. I have enclosed a sample output file.
>
>Total Pages Examined : 262141
>Total Pages Processed (Data) : 2
>Total Pages Failing ( Data) : 0
>Total Pages Processed (Index) : 0
>Total Pages Failing (Index) : 0
>Total Pages Empty : 262141
>Total Paqges Marked Corrupt : 0
>Total Pages Influx : 0
>
>
>I have been unable to locate any information on this topic in any of the
>books I have.
>We are running Oracle 7 Server v7.3.4 on an NT 4.0 server with sp3.0.
>
>Thanks in advance for your help,
>
>Michael
>
>
>
Received on Thu Apr 08 1999 - 05:16:34 CDT