Know the power of REPAIR utility in DB2

Hello my blog readers...

In this blog, I am going to explain how you can utilize REPAIR utility the most.

Everybody know REPAIR utility is popularly used for resetting the pending states of Index and Tablespaces.



Example 1: 
Everybody know REPAIR utility is popularly used for resetting the pending states of Index and Tablespaces.

//STEP3    EXEC DSNUPROC,UID='SSTRR',                            
//            UTPROC='',SYSTEM='DSN2'                                      
//SYSIN    DD *                                                            
  REPAIR OBJECT                                                            
  SET INDEX (ALL) TABLESPACE DTSG10.SSTRR NORBDPEND                  
  SET TABLESPACE DBTEST1.STEST PART 1 NOAUXCHKP                        
  SET TABLESPACE DBTEST1.STEST PART 4 NOCHECKPEND
/*

Example 2:
Suppose you want to delete a row corresponding to a ROWID mentioned in the referential violation constraint.


REPAIR
  LOCATE TABLESPACE DTSG10.TS1 RID (X'0000000503')
    DELETE




Example 3:
Replacing damaged data and verifying replacement.

* Repair the specified page of table space DTSG10.STEST1, as indicated by the LOCATE clause.
* Verify that, at the specified offset (50), the damaged data (0A00) is found, as indicated by the VERIFY clause.
* Replace the damaged data with the desired data (0D11), as indicated by the REPLACE clause.
* Initiate a dump beginning at offset 50, for 4 bytes, as indicated by the DUMP clause. You can use the generated dump to verify the replacement.

//STEP1    EXEC  DSNUPROC,UID='IUIQU1UH',UTPROC='',SYSTEM='DSN'

//SYSIN DD *

REPAIR OBJECT

  LOCATE TABLESPACE DSN8D81A.DSN8S81D PAGE X'02'

    VERIFY OFFSET 50 DATA X'0A00'

    REPLACE OFFSET 50 DATA X'0D11'

    DUMP OFFSET 50 LENGTH 4

Example 4:

Reporting whether catalog and directory DBDs differ. The following control statement specifies that REPAIR is to compare the DBD for DTSG10 in the catalog with the DBD for DTSG10 in the directory.

REPAIR DBD TEST DATABASE DTSG10

Example 5:

Reporting differences between catalog and directory DBDs. The following control statement specifies that the REPAIR utility is to report information about the inconsistencies between the catalog and directory DBDs for DTSG10. Run this job after you run a REPAIR job with the TEST option (as shown in example 4), and the condition code is not 0. In this example, SYSREC is the output data set, as indicated by the OUTDDN option.

REPAIR DBD DIAGNOSE DATABASE DSN8D2AP OUTDDN SYSREC

Example 6:

Repairing a table space with an orphan row. After running DSN1CHKR on table space SYSDBASE, assume that you receive the following message:

DSN1812I ORPHAN ID = 20 ID ENTRY = 0190 FOUND IN

         PAGE = 0000000024

From a DSN1PRNT of page X'0000000024' and X'0000002541', you identify that RID X'0000002420' has a forward pointer of X'0000002521'.

Repair the table space by taking the following actions:

1. Submit the following control statement, which specifies that REPAIR is to set the orphan's backward pointer to zeros:

      REPAIR OBJECT LOG YES

       LOCATE TABLESPACE DSNDB06.SYSDBASE RID X'0000002420'

        VERIFY OFFSET X'0A' DATA X'0000002422'

        REPLACE OFFSET X'0A' DATA X'0000000000'

Setting the pointer to zeros prevents the next step from updating link pointers while deleting the orphan. Updating the link pointers can cause DB2 to abnormally terminate if the orphan's pointers are incorrect.

2. Submit the following control statement, which deletes the orphan:

      REPAIR OBJECT LOG YES

       LOCATE TABLESPACE DSNDB06.SYSDBASE RID X'00002420'

        VERIFY OFFSET X'06' DATA X'00002521'

        DELETE

Example 7:

Updating version information. The control statement specifies that REPAIR is to update the version information in the catalog and directory for table spaces STEST1, STEST2, and STEST3.

REPAIR VERSIONS example control statement

//STEP1    EXEC DSNUPROC,UID='JUKQU3AS.REPAIR',TIME=1440,        

//         UTPROC='',                                            

//         SYSTEM='SSTR',DB2LEV=DB2A                             

//SYSIN    DD *                                                       

 REPAIR VERSIONS TABLESPACE DTSG10.STEST1                   

  REPAIR VERSIONS TABLESPACE DTSG10.STEST1 2                   

  REPAIR VERSIONS TABLESPACE DTSG10.STEST1 3  

So arm the knowledge of REPAIR Utility and set for the adventure.

Cheers..

Prakash C Singh.

IBM Certified DB2 DBA

How to display the key corresponding to RID Value

Hi,

When you run CHECK DATA utility to verify the violating the RI constraints, you may come across the following error message:

DSNUKERK - ROW (RID=X'0000000202') HAS NO PARENT FOR TSG10.TES3.CTES3A

Here the hexadecimal value X'0000000202' is the Row Identifier of the key of the child table which violates the RI constraint CTES3A.

If someone tell you to find out the record corresponding key to the RID value, then you can follow this approach.

There is one stand alone utility DSN1PRNT by the help of which you can print the VSAM file data.

RID value is always associated with the index of the table.

Hence by searching the RID value in underlying index dataset( for example DSN2.DSNDBD.DTSG10.X1TES300.I0001.A001)  of violating child table, we can get hold of the key.

Here is the sample JCL: Note: always search hexadecimal value in two double quotes.


//TSG10P JOB ,
// CLASS=L,MSGCLASS=O,NOTIFY=TSG10,MSGLEVEL=(1,1)
//****************************************************************
//*
//* JCL TO PRINT HEXADECIMAL DUMP OF DB2 IMAGE COPY
//*
//****************************************************************
//*
//STEP1    EXEC PGM=DSN1PRNT,
//         PARM='FORMAT,VALUE(''0000000202'')'
//SYSUT1   DD DSN=DSN2.DSNDBD.DTSG10.X1TES300.I0001.A001,DISP=SHR
//SYSPRINT DD SYSOUT=*
//*

The subset of the output looks like below:
===
UNIQUE KEYS FOLLOW:
KEY ENTRY:  IPKMAP(XI)='0038'X
KEY:
8001
RID:
0000000201
KEY ENTRY:  IPKMAP(XI)='003F'X
KEY:
8002
RID:
4000000202
KEY ENTRY:  IPKMAP(XI)='0046'X
KEY:
8005
RID:
4000000203

DSN1994I DSN1PRNT COMPLETED SUCCESSFULLY,  00000005 PAGES PROCESSED

Note:

1) To find out the violating rows you can create the exception table and track those and at the same time you can bring the table to RW mode from Check pending status.

2) Or you can use the REPAIR utility for DUMP/DELETE the violating rows By LOCATE TABLESPACE command.

So do not be afraid of seeing the RID hex values, just play with it by the available utilities


Cheers...
Prakash C Singh
IBM Certified DB2 DBA

Get ready for DB2 X

Hey...now-a-days SPEED is the new buzz around the world.

So DB2 for z/OS leads the race in RDBMS category with announcement of beta version of DB2 10 or DB2 X on 9th, February 2010.



Here are some major points in DB2 X for z/OS

1) This version gives you the best CPU reductions for transactions and batches (i.e. saving more money)

2) Second major benefit is Scalability (Enhanced query parallelism)

3) More on demand enhancement improves availability (more online changes for Data definitions, utilities and Subsystem)


4) DBAs will be happy to find improved database performance, scalability, and availability

5) Reduced memory management,  so growth is much simpler (10 times more users by avoiding memory constraints)

6) To support regulatory compliance, DBA to get more flexible security (More granularity)





7) Warehousing continues to evolve, with key trends matching System z and DB2 for z/OS strengths of performance, scalability, reliability, stability, availability, resilience, and security (On the fly Data compression)

8) SQL, pureXML, and web services extend usability and application portability for this platform

9) More concurrency for Catalog, Utilities and SQL

10) Improved productivity for Database admin, System admin and application programmers




Cheers...
Prakash C Singh
IBM Certified Database Administrator

Modelling your production system

Hello Blog readers,


Most of the times it is a real challenge to refresh data from production environment to test env with limited time and resources. But it is very important to know the future access path to be produced in production env while testing in development environment. This is basically needed to know the future performance problem associated due to access path chosen by the Optimizer.


Here is the extract of the DB2 administration guide which will guide you how to generate the exact access path in test system with respect to production system.

SELECT DISTINCT 'UPDATE SYSIBM.SYSTABLESPACE SET NACTIVEF='
CONCAT STRIP(CHAR(NACTIVEF))
CONCAT',NACTIVE='CONCAT STRIP(CHAR(NACTIVE))
CONCAT ' WHERE NAME=''' CONCAT TS.NAME
CONCAT ''' AND DBNAME ='''CONCAT TS.DBNAME CONCAT''';'
FROM SYSIBM.SYSTABLESPACE TS, SYSIBM.SYSTABLES TBL
WHERE TS.NAME = TSNAME
AND TBL.CREATOR IN (table creator_list)
AND TBL.NAME IN (table_list)
AND (NACTIVEF >=0 OR NACTIVE >=0);

==
SELECT 'UPDATE SYSIBM.SYSTABLES SET CARDF='
CONCAT STRIP(CHAR(CARDF))
CONCAT',NPAGES='CONCAT STRIP(CHAR(NPAGES))
CONCAT',PCTROWCOMP='CONCAT STRIP(CHAR(PCTROWCOMP))
CONCAT ' WHERE NAME='''CONCAT NAME
CONCAT ''' AND CREATOR ='''CONCAT CREATOR CONCAT''';'
FROM SYSIBM.SYSTABLES WHERE
CREATOR IN (creator_list)
AND NAME IN (table_list)
AND CARDF >= 0;
==
SELECT 'UPDATE SYSIBM.SYSINDEXES SET FIRSTKEYCARDF='
CONCAT STRIP(CHAR(FIRSTKEYCARDF))
CONCAT ',FULLKEYCARDF='CONCAT STRIP(CHAR(FULLKEYCARDF))
CONCAT',NLEAF='CONCAT STRIP(CHAR(NLEAF))
CONCAT',NLEVELS='CONCAT STRIP(CHAR(NLEVELS))
CONCAT',CLUSTERRATIO='CONCAT STRIP(CHAR(CLUSTERRATIO))
CONCAT',CLUSTERRATIOF='CONCAT STRIP(CHAR(CLUSTERRATIOF))
CONCAT' WHERE NAME='''CONCAT NAME
CONCAT ''' AND CREATOR ='''CONCAT CREATOR CONCAT''';'
FROM SYSIBM.SYSINDEXES
WHERE TBCREATOR IN (creator_list)
AND TBNAME IN (table_list)
AND FULLKEYCARDF >= 0;
==
SELECT 'UPDATE SYSIBM.SYSCOLUMNS SET COLCARDF='
CONCAT STRIP(CHAR(COLCARDF))
CONCAT',HIGH2KEY= X''' CONCAT HEX(HIGH2KEY)
CONCAT''',LOW2KEY= X''' CONCAT HEX(LOW2KEY)
CONCAT''' WHERE TBNAME=''' CONCAT TBNAME CONCAT ''' AND COLNO='
CONCAT STRIP(CHAR(COLNO))
CONCAT ' AND TBCREATOR =''' CONCAT TBCREATOR CONCAT''';'
FROM SYSIBM.SYSCOLUMNS
WHERE TBCREATOR IN (creator_list)
AND TBNAME IN (table_list)
AND COLCARDF >= 0;

SYSTABSTATS and SYSCOLDIST require deletes and inserts.
Delete statistics from SYSTABSTATS on the test subsystem for the specified tables
by using the following statement:
DELETE FROM (TEST_SUBSYSTEM).SYSTABSTATS
WHERE OWNER IN (creator_list)
AND NAME IN (table_list);

Use INSERT statements to repopulate SYSTABSTATS with production statistics that
are generated from the following statement:

SELECT 'INSERT INTO SYSIBM.SYSTABSTATS'
CONCAT '(CARD,NPAGES,PCTPAGES,NACTIVE,PCTROWCOMP'
CONCAT ',STATSTIME,IBMREQD,DBNAME,TSNAME,PARTITION'
CONCAT ',OWNER,NAME,CARDF) VALUES('
CONCAT STRIP(CHAR(CARD)) CONCAT ' ,'
CONCAT STRIP(CHAR(NPAGES)) CONCAT ' ,'
CONCAT STRIP(CHAR(PCTPAGES)) CONCAT ' ,'
CONCAT STRIP(CHAR(NACTIVE)) CONCAT ' ,'
CONCAT STRIP(CHAR(PCTROWCOMP)) CONCAT ' ,'
CONCAT '''' CONCAT CHAR(STATSTIME) CONCAT ''' ,'
CONCAT '''' CONCAT IBMREQD CONCAT ''' ,'
CONCAT '''' CONCAT STRIP(DBNAME) CONCAT ''' ,'
CONCAT '''' CONCAT STRIP(TSNAME) CONCAT ''' ,'
CONCAT STRIP(CHAR(PARTITION)) CONCAT ' ,'
CONCAT '''' CONCAT STRIP(OWNER) CONCAT ''' ,'
CONCAT '''' CONCAT STRIP(NAME) CONCAT ''' ,'
CONCAT STRIP(CHAR(CARDF)) CONCAT ');'
FROM SYSIBM.SYSTABSTATS
WHERE OWNER IN (creator_list)
AND NAME IN (table_list);

==
Delete statistics from SYSCOLDIST on the test subsystem for the specified tables
by using the following statement:
DELETE FROM (TEST_SUBSYSTEM).SYSCOLDIST
WHERE TBOWNER IN (creator_list)
AND TBNAME IN (table_list);

Use INSERT statements to repopulate SYSCOLDIST with production statistics that
are generated from the following statement:

SELECT 'INSERT INTO SYSIBM.SYSCOLDIST '
CONCAT '(FREQUENCY,STATSTIME,IBMREQD,TBOWNER'
CONCAT ',TBNAME,NAME,COLVALUE,TYPE,CARDF,COLGROUPCOLNO'
CONCAT ',NUMCOLUMNS,FREQUENCYF) VALUES( '
CONCAT STRIP(CHAR(FREQUENCY)) CONCAT ' ,'
CONCAT '''' CONCAT CHAR(STATSTIME) CONCAT ''' ,'
CONCAT '''' CONCAT IBMREQD CONCAT ''' ,'
CONCAT '''' CONCAT STRIP(TBOWNER) CONCAT ''' ,'
CONCAT '''' CONCAT STRIP(TBNAME) CONCAT ''','
CONCAT '''' CONCAT STRIP(NAME) CONCAT ''' ,'
CONCAT 'X''' CONCAT STRIP(HEX(COLVALUE)) CONCAT ''' ,'
CONCAT '''' CONCAT TYPE CONCAT ''' ,'
CONCAT STRIP(CHAR(CARDF)) CONCAT ' ,'
CONCAT 'X'''CONCAT STRIP(HEX(COLGROUPCOLNO)) CONCAT ''' ,'
CONCAT CHAR(NUMCOLUMNS) CONCAT ' ,'
CONCAT STRIP(CHAR(FREQUENCYF)) CONCAT ');'
FROM SYSIBM.SYSCOLDIST
WHERE TBOWNER IN (creator_list)
AND TBNAME IN (table_list);


Note about SPUFI:

• If you use SPUFI to execute the preceding SQL statements, you might need to increase the default maximum character column width to avoid truncation.
• Asterisks (*) appear in the examples to avoid having the semicolon interpreted as the end of the SQL statement. Edit the result to change the asterisk to a semicolon.

Access path differences from test to production: When you bind applications on the
test system with production statistics, access paths should be similar but still may
be different to what you see when the same query is bound on your production
system.

The access paths from test to production could be different for the following possible reasons:

• The processor models are different.
• The number of processors are different. (Differences in the number of processors can affect the degree of parallelism that is obtained.)
• The buffer pool sizes are different.
• The RID pool sizes are different.
• Data in SYSIBM.SYSCOLDIST is mismatched. (This mismatch occurs only if some of the previously mentioned steps mentioned are not followed exactly).
• The service levels are different.
• The values of optimization subsystem parameters, such as STARJOIN, NPGTHRSH, and PARAMDEG (MAX DEGREE on installation panel DSNTIP8) are different.
• v The use of techniques such as optimization hints and volatile tables are different.

Tools to help: If your production system is accessible from your test system, you
can use DB2 PM EXPLAIN on your test system to request EXPLAIN information
from your production system. This request can reduce the need to simulate a
production system by updating the catalog.

You can also use the DB2 Visual Explain feature to display the current
PLAN_TABLE output or the graphed access paths for statements within any
particular subsystem from your workstation environment. For example, if you have
your test system on one subsystem and your production system on another
subsystem, you can visually compare the PLAN_TABLE outputs or access paths
simultaneously with some window or view manipulation. You can then access the
catalog statistics for certain referenced objects of an access path from either of the
displayed PLAN_TABLEs or access path graphs.

Cheers...
Prakash C. Singh
IBM Certified DB2 DBA

Fileaid for DB2 Setup Error - FDBA623 CAF error 00F30034

Hi,

There are certain times after installation of Fileaid for DB2, users get this kind of error.

"FDBA623 CAF error 00F30034 - Plan name unauthorized."

Normally as part of installation/upgrade of Fileaid for DB2, DBA does the bind of the new plan.

As a security measure, DB2 does not allow the users to allow the access to the plan unless Execute privilege is granted to it explicitly.

Hence if the DBA forgets to grant Execute privilege, the uses will get the message like "FDBA623 CAF error 00F30034 - Plan name unauthorized." when one tries to connect to fileaid for DB2.

As a best practice for DBA, it is recommended that as soon as the bind finishes, he should give the require privileges to the users.

In this Example Granting Execute privilege for plan FDPN610 and FDOM610 to Public could have avoided the error message mentioned in subject line.

Cheers..
Prakash C Singh
IBM Certified DB2 DBA

Display current threads when you get DB2 Not Operational message

Hi Friends,

Here is one typical problem you usually get when you tried to Stop DB2 subsystem. You just fired the command to stop the DB2 subsystem, but DB2 is not coming down.

After having a thought...you may assume there are certain active dedicated threads from a started task (DB2 related application or any job). The interesting fact is when you try to DISPLAY Threads through DB2 Panels to execute DB2 commands, it  will give you a Message like DB2 Not Operational for the Subsystem.

Here is the trick:
If you know the Character for DB2 subsystem (You can get it from Zparms), you can fire the Display command from console.

For example in spool you can type

/+DIS THD(*)

Here '+' is the character for the Subsystem.

Now you can close the started task or kill the job to proceed further.

Regards,

Prakash Singh

IBM Certified DB2 DBA

Tape backup File not found for DSN1COPY job

Hi,

Here is one of the common problems that many of you might have faced.

Problem: One of your development guys ask to restore the table to a old backup image. Now you got the tape file name from the SYSIBM.SYSCOPY, but when you put this file name in 3.4, you are not able to find the file. This is just a JCL problem rather than a Database problem.

Solution:

You can still use this file (like in job for DSN1COPY), if it is not overwritten by any other job. You cannot find this file as this might have uncatalogued by the policy you have in your system. You can use this file by providing additional information in JCL DD statement.

The additional information are:
1) Unit info
2) VOLUME Serial Number
3) File sequence number i.e LEBEL parameter

Now get your job done!!!

Cheers!!
Prakash C Singh
IBM Certified Database Administrator