IV59514: ZEDC EXPRESS DECOMPRESSION NOT USED SOMETIMES ON Z/OS

APAR status

• Closed as program error.

Error description

• Error Message: On z/OS, zEDC Express (i.e., hardware)
  decompression is not used when using some Java classes like
  GZIPInputStream even though the buffer sizes specified are
  sufficiently large.
  .
  Stack Trace: N/A
  .
  

Local fix

Problem summary

• The problem is caused because the native decompression API
  inflate is called before the input buffer size is set when using
  GZipInputStream class. This causes the input buffer size to be
  set to zero (i.e., less than the default inflate threshold
  size), which makes zEDC Express code to fall back to software
  compression instead of using zEDC Express compression.
  

Problem conclusion

• This APAR will be fixed in the following Java Releases:
     7 R1 SR1       (7.1.1.0)
     7    SR7       (7.0.7.0)
  .
  The zEDC Express Exploitation code in the z/OS JDK has been
  updated to defer the decision to route the decompression to
  hardware or software until we get the non zero input buffer and
  avoid unnecessary processing.
  

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:

Fix information

• Fixed component name

  JAVA CLASS LIBS

• Fixed component ID

  620700130

Applicable component levels

• R700 PSY

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