CHKOBJDMG -- Check Object Damage

CHKOBJDMG CHECK OBJECT DAMAGE TAALIBF
The Check Object Damage command checks all of the objects in one or all libraries for damage. The check occurs by saving each object to a save file in QTEMP. A typical command is entered as: CHKOBJDMG LIB(xxxxx) A report is output to the spooled file OBJDMG. Exceptions are noted: If the object is already marked as damaged, an exception line is printed. If the object cannot be successfully saved, an exception is printed. The most typical error found will be that the object is locked and cannot be saved. To determine the actual cause that the object could not be saved, the job log must be reviewed. The CPD3761 message indicates the locked condition. If damage is detected by the save command, the object will now be marked as damaged. Another execution of CHKOBJDMG will show the object as damaged in the printed listing. A diagnostic in the job log will note the damage condition. Successfully executing the CHKOBJDMG command does not ensure that any undetected damage exists. See the Restrictions section. The objects are saved one at a time to a save file in QTEMP. There must be enough room in the save file to hold the largest object you will be checking. If you have large data base objects, you may not have enough room to save them to the save file. If so, specify CHKPF(NO) to avoid checking these objects. The checking that occurs by CHKOBJDMG only ensures that all of the pages of an object exist to be saved. This is a sanity test and does not ensure that the bytes will perform a valid function. Data base files take up the most amount of storage on a typical system and can have damage within the data portion of the object. The CHKOBJDMG command will detect certain damage, but it will not detect damage in the data portion of the object. To do a better validation of data base files, you should consider the use of the VALDBF tool (includes the VALMNYDBF command). VALMNYDBF will cause all physical members in a file, a library or all user libraries to be processed. The processing includes reading all of the records, checking for valid numeric data (if there are any externally described numeric fields) and checking fields based on any DDS validity checking specifications (e.g. RANGE). If you suspect damage on your system, a reasonable test would be to use CHKOBJDMG with CHKPF(NO) and VALMNYDBF for all user libraries. Note that both of these functions are very long running. If you suspect damage in a library, both commands could be used against a specific library. Libraries and objects not saved ------------------------------- The following libraries cannot be specified. If LIB(ALL) is specified, they are bypassed. QSYS QDOCx QSPL The following object types cannot be saved by SAVOBJ. If found in a library, they are bypassed: DOC FLR PRDLOD PRDDFN Command parameters CMD ------------------ LIB The library to be checked. ALL may be specified to check all libraries. See the discussion of libraries and objects not saved. You must have USE authority to the TAADSPADP authorization list to specify ALL. CHKPF A YES/NO value for whether data base files should be checked by saving them. YES does not ensure that the file contains valid data. See the VALDBF TAA tool to check the file. If YES is specified, you must have sufficient storage space on your system to save the largest file in the library. Restrictions ------------ Checking for damage by performing a save does not check for all potential damage conditions. It performs a sanity check that all objects can be saved. It is possible for the system to save undetected damage. For example: * If a program object has been damaged so that the instruction stream cannot be executed (e.g. invalid machine operations), this will not be detected unless the instructions are executed. If a data base object contains data that is incorrect based on the DDS description of the data (e.g. numeric fields do not contain valid digits), the error will not be detected until the field is used in a numeric operation. The TAA command VALMNYDBF will find this type of error. In front of every data base record is a byte used by the system to determine if the record has been deleted. If this byte contains an invalid bit combination, the damage condition will not be reported until the record is read by a data management function. The save function picks up blocks of data and does not check the leading byte. The VALMNYDBF command will find this type of damage. ** Logical file objects are checked for damage, but not the access paths. Logical file access paths are only saved with the based on physical file if specifically requested on the save command (they are not saved in the tool). See also the discussion of libraries and objects not saved. Prerequisites ------------- The following TAA Tools must be on your system: DSPOBJDA DSPOBJD with adopt (part of DSPADP tool) EDTVAR Edit variable RTVSPCAUT Retrieve special authority RTVSYSVAL3 Retrieve system value 3 SNDCOMPMSG Send completion message SNDESCMSG Send escape message SNDSTSMSG Send status message Implementation -------------- None, the tool is ready to use. Objects used by the tool ------------------------ Object Type Attribute Src member Src file ------ ---- --------- ---------- ---------- CHKOBJDMG CMD TAALIBF QATTCMD TAALIBFC PGM CLP TAALIBFC QATTCL

CHKOBJDMG       CHECK OBJECT DAMAGE                    TAALIBF


The Check  Object Damage command  checks all of  the objects in  one or
all libraries for damage.

The check occurs by saving each object to a save file in QTEMP.

A typical command is entered as:

        CHKOBJDMG   LIB(xxxxx)

A report is output to the spooled file OBJDMG.  Exceptions are noted:

  **   If the  object is already  marked as damaged,  an exception line
       is printed.

  **   If  the  object cannot  be successfully  saved, an  exception is
       printed.  The most typical  error found will be that  the object
       is locked  and cannot be saved.   To determine  the actual cause
       that  the  object  could  not be  saved,  the  job  log  must be
       reviewed.  The CPD3761  message indicates the locked  condition.

       If damage is  detected by the save command, the  object will now
       be  marked  as damaged.    Another execution  of  CHKOBJDMG will
       show  the  object  as  damaged  in  the  printed  listing.     A
       diagnostic in the job log will note the damage condition.

Successfully executing the  CHKOBJDMG command does not ensure  that any
undetected damage exists.  See the Restrictions section.

The objects  are saved one  at a time to  a save file in  QTEMP.  There
must  be enough room  in the save  file to hold  the largest object you
will be checking.   If you  have large data  base objects, you  may not
have  enough room  to  save them  to the  save  file.   If  so, specify
CHKPF(*NO) to avoid checking these objects.

The  checking that  occurs by  CHKOBJDMG only ensures  that all  of the
pages of an object exist to be  saved.  This is a sanity test and  does
not ensure that the bytes will perform a valid function.

Data  base files  take  up the  most  amount of  storage  on a  typical
system  and can  have damage  within  the data  portion of  the object.
The CHKOBJDMG  command will  detect  certain damage,  but it  will  not
detect damage  in  the data  portion of  the object.   To  do a  better
validation  of data  base files,  you should  consider  the use  of the
VALDBF tool (includes the VALMNYDBF command).

VALMNYDBF  will cause all physical members in  a file, a library or all
user libraries to  be processed.   The processing includes reading  all
of  the records,  checking for  valid numeric  data (if  there  are any
externally  described numeric fields) and checking  fields based on any
DDS validity checking specifications (e.g.  RANGE).

If you suspect  damage on your  system, a reasonable  test would be  to
use CHKOBJDMG  with CHKPF(*NO)  and VALMNYDBF  for all  user libraries.
Note  that both  of  these functions  are very  long running.    If you
suspect damage in  a library,  both commands  could be  used against  a
specific library.

Libraries and objects not saved
-------------------------------

The  following  libraries  cannot  be  specified.     If  LIB(*ALL)  is
specified, they are bypassed.

       QSYS
       QDOCx
       QSPL

The following  object types cannot be  saved by SAVOBJ.  If  found in a
library, they are bypassed:

      *DOC
      *FLR
      *PRDLOD
      *PRDDFN

Command parameters                                    *CMD
------------------

   LIB           The  library to be checked.   *ALL may be specified to
                 check  all   libraries.     See   the  discussion   of
                 libraries and  objects not saved.  You  must have *USE
                 authority  to  the  TAADSPADP  authorization  list  to
                 specify *ALL.

   CHKPF         A *YES/*NO value  for whether  data base files  should
                 be  checked by  saving  them.   *YES  does not  ensure
                 that  the file  contains valid data.   See  the VALDBF
                 TAA tool to check the file.

                 If  *YES  is  specified,  you  must  have   sufficient
                 storage  space on  your  system  to save  the  largest
                 file in the library.

Restrictions
------------

Checking  for  damage by  performing  a  save does  not  check for  all
potential  damage  conditions.   It performs  a  sanity check  that all
objects can be saved.

It  is  possible for  the  system  to  save  undetected  damage.    For
example:

  **   If a  program object  has been damaged  so that  the instruction
       stream  cannot be executed  (e.g.   invalid machine operations),
       this  will  not   be  detected   unless  the  instructions   are
       executed.

  **   If a data  base object contains data that is  incorrect based on
       the  DDS description of  the data (e.g.   numeric fields  do not
       contain valid  digits), the  error will  not be  detected  until
       the field  is  used in  a numeric  operation.   The TAA  command
       VALMNYDBF will find this type of error.

  **   In  front of  every  data  base record  is  a byte  used  by the
       system  to determine  if the record  has been deleted.   If this
       byte contains an  invalid bit combination, the  damage condition
       will  not  be  reported until  the  record  is  read by  a  data
       management  function.   The  save  function picks  up  blocks of
       data and  does  not  check  the leading  byte.    The  VALMNYDBF
       command will find this type of damage.

  **   Logical  file  objects  are  checked for  damage,  but  not  the
       access  paths.  Logical  file access  paths are only  saved with
       the based  on physical  file if  specifically requested  on  the
       save command (they are not saved in the tool).

See also the discussion of libraries and objects not saved.

Prerequisites
-------------

The following TAA Tools must be on your system:

     DSPOBJDA     DSPOBJD with adopt (part of DSPADP tool)
     EDTVAR       Edit variable
     RTVSPCAUT    Retrieve special authority
     RTVSYSVAL3   Retrieve system value 3
     SNDCOMPMSG   Send completion message
     SNDESCMSG    Send escape message
     SNDSTSMSG    Send status message

Implementation
--------------

None, the tool is ready to use.

Objects used by the tool
------------------------

   Object        Type        Attribute      Src member    Src file
   ------        ----        ---------      ----------    ----------

   CHKOBJDMG     *CMD                       TAALIBF       QATTCMD
   TAALIBFC      *PGM           CLP         TAALIBFC      QATTCL

Added to TAA Productivity tools April 1, 1995

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