IT20075: RSS PRIMARY SERVER CAN HANG/LOCK UP WITH RSS_SEND/RSS_RECV THREADS SPINNING ON THE BACKLOGWAITLOCK SPIN LOCK

APAR status

• Closed as program error.

Error description

• This is the same problem as APAR IC78772.  The primary can hang
  running constantly on the cpu vps trying to acquire a spin lock.
  Both RSS_Send and RSS_recv threads can hang. The RSS_Send will
  wait on spin lock in getPagesFromCache() and RSS_Recv in
  cloneSourceRecvThread(). The thread holding the backlogWaitLock
  spin lock will have a stack like:
  
  yield_processor_mvp()
  mt_lock_wait()
  mt_lock()
  cloneCacheLogPageInt()
  cloneCacheInt()
  cloneCacheLogPage()
  logwrite()
  log_put()
  logm_write()
  logputx()
  rscommit()
  iscommit()
  sqiscommit()
  sqcommit()
  aud_sqcommit()
  sql_commit()
  sq_commit()
  sqmain()
  listen_verify()
  spawn_thread()
  th_init_initgls()
  startup()
  
  The defect occurs with 1 or 2 CPU VPs.  Since the threads are
  running constantly in the CPU VPs, the sqlexec thread cannot
  continue even if the mutex is already free.
  

Local fix

• Configure 3 or more CPU VPs.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All users                                                    *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Update to IBM Informix Server 12.10.xC9                      *
  ****************************************************************
  

Problem conclusion

• Problem Fixed In IBM Informix Server 12.10.xC9
  

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

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels

• RA10 PSN

     UP

• RA10 PSY

     UP

• RB10 PSN

     UP

• RB10 PSY

     UP

• RB50 PSN

     UP

• RB50 PSY

     UP

• RB70 PSN

     UP

• RB70 PSY

     UP

• RC10 PSN

     UP

• RC10 PSY

     UP