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2936708 - Thread usage increases through the introduction of AIO feature post upgrading to IQ 16.1 SP04 - SAP IQ


  • SAP IQ 16.1 SP04 introduces a new feature for Asynchronous I/O (AIO) that changes the internal threading model of IQ.

  • Post upgrading to SAP IQ 16.1 SP04 customers may notice that the thread usage in the IQ process increases.

  • Some queries may fail with "not enough server threads available for this query" "SQL Anywhere Error -1010011"  messages seen in the iqmsg file. 

  • Post upgrading to SAP IQ 16.1 SP04 customers may also notice  in the std err file  (or console log) that the figure  for the -iqmt setting has increased significantly without the customer having made any manual chages to the startup switch in their .cfg configuration file.  

  • Customers may also start to notice messages like "Using AIO based prefetch manager” in the console log at startup.
  • IQ Sysmon debug monitoring data shows a significant increase in thread usage.



SAP IQ 16.1 SP04 upwards on any platform


SAP IQ 16.1


sybase, crash, abort, SP_04, IQ161, IQ 16-1, upgrade, iqmt, -iqmt, iqnumbercpus, - iqnumbercpus, threads, Max_Threads_Per_Connection, Max_Threads_Per_Team, sp_iqsysmon, insufficient threads, -1010011, "thread starvation",  "out of thread", "-1010011", async,  feature , 'I/O' , input, output, 'file-system', mpx , KBA , BC-SYB-IQ , Sybase IQ , Product Enhancement

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