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IMC Serial Queries Run in Parallel on RAC (Doc ID 2373556.1)

Last updated on APRIL 03, 2020

Applies to:

Oracle Database - Enterprise Edition - Version and later
Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.


Problem Summary
Query runs in parallel when it should be running in serial.

Problem Description

No parallel hint in query

No dop set on table or indexes

Instance = 1 on table and indexes

The table is in memory

This is RAC

Query will run in parallel

PX trace file shows:


kkopqSetForceParallelProperties: Hint:no >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Query: compute:yes forced:no forceDop:0
2018-03-02 13:31:57.521*:PX_Messaging:kxfp.c@19689:kxfpActiveInstList(begin):
Get instance list for state:open
2018-03-02 13:31:57.521*:PX_Messaging:kxfp.c@19819:kxfpActiveInstList(end):
groupName:[] #instances=2 <<<<<<<<<<<<<<<<
kxfplist status:2 #insts:2
2018-03-02 13:31:57.521*:PX_Messaging:kxfp.c@20626:kxfpiinfo():
inst [cpus:mxslv:bc(MB) :pga_target(MB):type]
1 [32 :1280 :5984 :5120 :HUB]
2 [32 :1280 :6400 :5120 :HUB]
instance_id:1, cpu_count:32 #pg:1
instance_id:2, cpu_count:32 #pg:1
total cpu_count:64 #pg:2
kkopqInMemRacDOPAffinity: #nodes=2 - CapDOP=128 - Rounded from 1 to 2 - Capped?=no
Global Manual Dop: 2 - Rounded?: yes <<<<<<<<<<<<<<<<<<<<<<<<
kkopqSetDopReason: Reason why we chose this DOP is: table property. <<<<<<<<<<<<<<<<<table has dop=1 but this is a 2 node RAC system.
table property forces parallelism with dop=2


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