2898849 - Query slower on 16.1 SP04 than on 16.1 SP02 - SAP IQ

Symptom

A query could run slower on SAP IQ 16.1 SP04 than on SAP IQ 16.1 SP02
On both versions, same IQ start up parameters are used
On both versions, the query tree is the same
On both versions, there are similar row counts and data distribution in the tables
The main difference is, on SAP IQ 16.1 SP04, in the query plan, "Max. Active Parallel Threads" is always 1

On 16.1 SP02

From the query plan, CPU is high ~100%

#10 Root

Generated Result Rows	1,817
Estimated Result Rows	67,477
Est. Temp Space Used (Mb)	110.0
Act. Temp Space Used (Mb)	239.0
Threads used for executing local invariant predicates	1
Elapsed time	0:00:51

#5 Order By Node

Max. Possible Parallel Arms	4
Max. Active Parallel Threads	3

#6 Order By Node

Max. Possible Parallel Arms	4
Max. Active Parallel Threads	4

On 16.1 SP04

From the query plan, CPU is low ~25%

#10 Root

Generated Result Rows	1,784
Estimated Result Rows	67,477
Est. Temp Space Used (Mb)	112.0
Act. Temp Space Used (Mb)	74.5
Threads used for executing local invariant predicates	1
Elapsed time	0:02:16

#5 Order By Node

Max. Possible Parallel Arms	4
Max. Active Parallel Threads	1

#6 Order By Node

Max. Possible Parallel Arms	4
Max. Active Parallel Threads	1

Environment

SAP IQ 16.1 SP 04

Product

SAP IQ 16.1

Keywords

CR821185; CR#821185; 821185; thread; threads; "Max. Active Parallel Threads"; Active; Parallel; "Max. Possible Parallel Arms"; Possible ; Parallel ; Arms; Max; -iqmt; iqmt; performance; slow , KBA , BC-SYB-IQ , Sybase IQ , Bug Filed

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