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Parallel Query Runs in Serial ON RAC when Using Default SERVICE_NAME (Doc ID 2603641.1)

Last updated on JULY 15, 2021

Applies to:

Oracle Database - Enterprise Edition - Version and later
Information in this document applies to any platform.


NOTE: In the images and/or the document content below, the user information and environment data used represents fictitious data from the Oracle sample or bulit-in schema(s), Public Documentation delivered with an Oracle database product or other training material.  Any similarity to actual environments, actual persons, living or dead, is purely coincidental and not intended in any manner.


The following query runs in serial when connecting to the database using SERVICE_NAME. Runs in parallel if connecting to the database using SID.

select /*+ parallel(8) full(t) */ count(1)  from  <table> t;


PX trace file shows:


No active instances, disable parallelism >>>>>>
2019-10-09 16:16:27.679712*:PX_Messaging:kxfp.c@18551:kxfpActiveInstList(begin):
Get instance list for state:open
2019-10-09 16:16:27.679712*:PX_Messaging:kxfp.c@18679:kxfpActiveInstList(end):
groupName:[<>] #instances=0
kxfplist status:2 #insts:0
 total cpu_count:28 #pg:2
2019-10-09 16:16:27.679712*:PX_Granule:kxfr.c@8553:kxfrDefaultDOP():
deg:28 tpc:1 #cpus:28 cap:-1 service:IODSC3RO pig: ser:0 locl:0
kkfdPaPrm: pq Default DOP is computed (28)
kkfdiPaPrm: dop:8 serial(serial - DOP = 1 (PX not allowed): parallel_max_servers == 0 on all instances: current process is slave or: current process is background process or: single process or: PX not installed or: running in serializable mode




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