IJ04647: AVOID OPENING THE SHARED CACHE MEMORY CONTROL FILE TO RETRIEVE TOTAL CACHE SIZE FOR NON-PERSISTENT CACHE

APAR status

• Closed as program error.

Error description

• Error Message: The following tracepoints will be generated
  frequently (if enabled):
  03:38:20.627963973  0x000000000c20c500 j9shr.1060          Entry
       >CC allocate: Entering with type=1, len=4, len2=0,
  separateBufferSize=808
  03:38:20.627965776  0x000000000c20c500 j9prt.56            Entry
       >j9shmem_stat entered, name =
  C290M4F1A64_memory_liberty-IZUSVR_G35
  03:38:20.627966626  0x000000000c20c500 j9prt.699           Entry
       >ControlFileFDWithWriteLock (Start)
  03:38:20.628153531  0x000000000c20c500 omrport.256
  03:38:20.628980460  0x000000000c20c500 j9prt.701           Exit
       <ControlFileFDWithWriteLock (Success)
  .
  Stack Trace: The following stacktrace corresponds to the
  frequent file accesses:
  omrfile_open()
  j9shmem_stat()
  SH_OSCachesysv::getTotalSize()
  SH_CompositeCacheImpl::getTotalSize()
  SH_CompositeCacheImpl::getUsedBytes()
  SH_CompositeCacheImpl::allocate()
  .
  In products using the jvm that switch/change the current userid
  that the jvm is running with during the course of execution,
  this may cause file access permission-related messages for a
  non-persistent shared cache memory control file to be issued by
  the security management component of the operating system.
  For e.g., on z/OS, the following message may be generated (this
  may be generated in spite of the -Xshareclasses:groupaccess
  subparameter  not being specified) :
  23.38.20 STC00063  ICH408I USER(U2 ) GROUP(G1)
  NAME(####################)  405
      405
  /pathtocache/javasharedresources/C290M4F4051A64_memory__XYZU1_G3
  5
      405               CL(FSOBJ   )
  FID(E9D4C6F0F4F2172500000000054E1360)
      405               INSUFFICIENT AUTHORITY TO OPEN
      405               ACCESS INTENT(RW-)  ACCESS ALLOWED(GROUP
     R--)
      405               EFFECTIVE UID(0000009001)  EFFECTIVE
  GID(0000009003)
  Note that the shared cache memory control filename in the second
  line of the above message may vary depending on the
  -Xshareclasses:name subparameter.
  

Local fix

Problem summary

• The jvm was frequently opening the shared cache memory control
  file to retrieve total cache size for non-persistent cache.
  

Problem conclusion

• The jvm was changed to avoid frequent accesses to the shared
  cache memory control file to retrieve total cache size for
  non-persistent cache.
  .
  This APAR will be fixed in the following Java Releases:
     8    SR5 FP11  (8.0.5.11)
  .
  Contact your IBM Product's Service Team for these Service
  Refreshes and Fix Packs.
  For those running stand-alone, information about the available
  Service Refreshes and Fix Packs can be found at:
             https://www.ibm.com/developerworks/java/jdk/
  

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

  J9 COMMON CODE

• Fixed component ID

  620700127

Applicable component levels

• R270 PSY

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