2563769 - sp_iqcheckdb with verify mode got unresponsive even when no user connections.

• Symptom 1:
  sp_iqcheckdb with verify mode got unresponsive even when no user connections.
• Symptom 2:
  checkpoint process as part of backup could trigger deadlock situation resulting in server hang state
  ValidateBackup              
  IQ Checkpoint position: 0   
  Chk                         
  ChkDone [NumTxnCP: 11]      
  IQ Checkpoint block: 6710946
  PrepareForBackup 
• Thread in stacktrace during the hang:
           __lll_lock_wait
           _L_lock_812
           pthread_mutex_lock
           hos_dualmutex::LockAndPromote
           s_blockmap::RegisterPhysicalBlockId
           s_blockmap::AllocOrReallocPhysicalBlocks
           s_buf::Write

SAP IQ 16.1

KBA , BC-SYB-IQ , Sybase IQ , Problem