3420669 - SAP IQ - slower performance with an "update" statement when higher "-iqmt" applied

• Found an "update" statement runs slower when higher "-iqmt" applied.

--problematic "update" statement
UPDATE #table01 t1
SET col1 = 100*t2.col7
FROM #table02 t2,
WHERE t2.col4 = t1.col4
AND t2.col2 = t1.col3
AND t2.col3 = (select max(col3) from #table02 where col4=t2.col4 and col3 <= t1.col5
AND col2 = t2.col2 and col6 = t2.col6 );

• Following is the performance result of the update SQL with SP05.09 on customer's env ( 16 physical cores ) per several "-iqmt" tried.

(1) -iqmt   200 / Elapsed Time 0:00:21.856386
(2) -iqmt   983 / Elapsed Time 0:00:55.809667 ==> default "-iqmt" calculated automatically
(3) -iqmt 1024 / Elapsed Time 0:00:55.637338
(4) -iqmt 2048 / Elapsed Time 0:01:57.132944
(5) -iqmt 3072 / Elapsed Time 0:04:16.061877
(6) -iqmt 4096 / Elapsed Time 0:06:05.639133

• SAP IQ 16.1 SP03.07
• SAP IQ 16.1 SP05.09 

number of thread, "-iqmt", , KBA , BC-SYB-IQ , Sybase IQ , BW-SYS-DB-IQ , BW on HANA with Sybase IQ Near-line Storage , Problem