After you locate the DBD in the dump, the DBD header and
chain of files can be analyzed for inconsistencies.
To check the DBD header and chain of files:
- Check the DBD header.
The control block identifier
(first 2 bytes of the DBD header) is X'2039'. At offset X'04' is the DBD eye-catcher.
- Cross-check the DBD with the Db2 catalog.
Issue the following SQL statement, specifying the DBID for
the DBD being checked.
SELECT NAME FROM SYSIBM.SYSDATABASE
WHERE DBID=dbid;
The result from this SELECT statement
should be one row, and the name should equal the name found in the
field named OBDDBNAM. If the number of rows that are returned is not
1 or the name does not equal the name found in OBDDBNAM, make a note
of the error.
- Check the OBD file chain.
The OBDDFILE field
in the OBDDBD contains the OBID of the first file OBD (OBDFILE). The
OBDFINX field in the OBDFILE contains either 0 or the OBID of the
next file OBD. (A zero indicates that the last file OBD in the chain.)
For each file OBD (indicated by an OBDTYPE field that equals binary B'10') on the file
chain, mark it and perform the check that is described under Checking the files.
If
the file chain is damaged (that is, the OBD located is not a file
OBD), make a note of the error.
- After you complete this procedure, no errors are found
and if all OBIDs are marked, the structure of the DBD is probably
consistent. If there are one or more unmarked OBIDs, then there is
one or more errors.
- If any errors are found when you analyze the structure
of the DBD, contact the IBM® support
center and describe the analysis that was done.