PM76256: INCORRECT DATA RETURNED ACCESSING A P12 FILE WITH MANY BLOCKS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• File is a very large striped dataset with over 2 million blocks
  (1 record per block). When using P12 to access this file
  random data is returned instead of the data in the requested
  record.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of the APL2 "Files as Variables"       *
  *                 facility, Processor 12, on z/OS.             *
  ****************************************************************
  * PROBLEM DESCRIPTION: After opening a very large file         *
  *                      with many blocks using Processor 12,    *
  *                      subsequent accesses of records          *
  *                      in the file return bad data.            *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The problem was experienced with a file that had close to 3
  million records, and a blocksize equivalent to its record size.
  
  For performance reasons, APL2 attempts to maintain a table of
  record information for each block in the file. With almost 3
  million blocks, APL2 was unable to obtain enough storage to
  create a complete table for all blocks in the file.
  
  There was a logic error in the code for handling incomplete
  block tables, which caused the code for locating a record
  outside the range of the block table to be used when the index
  was actually within the range of the block table.
  

Problem conclusion

• The logic has been changed to branch to the correct location
  for finding records within the range of the block table.
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UK83540

Modules/Macros

•    AP2TFNSD
  

Fix information

• Fixed component name

  APL2

• Fixed component ID

  566889901

Applicable component levels

• R222 PSY UK83540

     UP12/11/16 P F211

Fix is available

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