Using DBVERIFY to Validate a Segment

In this mode, DBVERIFY enables you to specify a table segment or index segment for verification. It checks to ensure that a row chain pointer is within the segment being verified.

This mode requires that you specify a segment (data or index) to be validated. It also requires that you log on to the database with SYSDBA privileges, because information about the segment must be retrieved from the database.

During this mode, the segment is locked. If the specified segment is an index, then the parent table is locked. Note that some indexes, such as IOTs, do not have parent tables.

DBVERIFY Syntax When Validating a Segment

The syntax for DBVERIFY when you want to validate a segment is as follows:

Description of the illustration dbverify_seg.eps follows
Description of the illustration dbverify_seg.eps

DBVERIFY Parameters When Validating a Single Segment

Descriptions of the DBVERIFY parameters used to validate a single segment are as follows:

Parameter Description

USERID

Specifies your username and password.

SEGMENT_ID

Specifies the segment to verify. It is composed of the tablespace ID number (tsn), segment header file number (segfile), and segment header block number (segblock). You can get this information from SYS_USER_SEGS. The relevant columns are TABLESPACE_ID, HEADER_FILE, and HEADER_BLOCK. You must have SYSDBA privileges to query SYS_USER_SEGS.

HIGH_SCN

When a value is specified for HIGH_SCN, DBVERIFY writes diagnostic messages for each block whose block-level SCN exceeds the value specified.

This parameter is optional. There is no default.

LOGFILE

Specifies the file to which logging information should be written. The default sends output to the terminal display.

FEEDBACK

Causes DBVERIFY to send a progress display to the terminal in the form of a single period (.) for n number of pages verified during the DBVERIFY run. If n = 0, then there is no progress display.

HELP

Provides online help.

PARFILE

Specifies the name of the parameter file to use. You can store various values for DBVERIFY parameters in flat files. This enables you to customize parameter files to handle different types of data files and to perform specific types of integrity checks on data files.

Sample DBVERIFY Output For a Validated Segment

The following is a sample of the output that would be shown for a DBVERIFY operation to validate SEGMENT_ID 1.2.67.

DBVERIFY - Verification starting : SEGMENT_ID = 1.2.67
 
DBVERIFY - Verification complete
 
Total Pages Examined         : 8
Total Pages Processed (Data) : 0
Total Pages Failing   (Data) : 0
Total Pages Processed (Index): 1
Total Pages Failing   (Index): 0
Total Pages Processed (Other): 2
Total Pages Processed (Seg)  : 1
Total Pages Failing   (Seg)  : 0
Total Pages Empty            : 4
Total Pages Marked Corrupt   : 0
Total Pages Influx           : 0
Highest block SCN            : 7358 (0.7358)