Parallelism I/O wait

[Roshan]

Oracle Database 12.2.0
RHEL 7.4
Storage: Huawei Oceanstore 6800 V3
8 cores CPU Intel (Intel(R) Xeon(R) CPU E5-2697 v2 @ 2.70GHz)
32 GB RAM

Hi Erman,

I am executing the query below from a remote server

SELECT SUM("A1"."VOLIN"+"A1"."VOLOUT"),"A1"."POSTPRE","A1"."MSISDN",SYSDATE@!-2,SYSDATE@!-92,SYSDATE@!-2 FROM "MOBILE_DATA" "A1" WHERE "A1"."TIME_TRUNC">=SYSDATE@!-92 AND "A1"."TIME_TRUNC"<=SYSDATE@!-2 AND SYSDATE@!-2>=SYSDATE@!-92 GROUP BY "A1"."POSTPRE","A1"."MSISDN"

The table MOBILE_DATA is located on a server on Oceanstore storage with ASM configured(please see above specs). Parallelism with DOP 32 has been enabled on the table to make it faster.

I see that I/O is high despite ASm is configured. Why is this so?

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Thanks,

Roshan

[ErmanArslansOracleBlog]

ASM is a volume manager.
You do parallel IO and it is normal to have a load on your storage.
You do a big Full Table Scan in parallel.
I didn't understand what you are asking to me here?

Bytheway, your AWR doesn't include any data for Tablespace and Datafile IO sections..

[Roshan]

OK. I wanted to confirm that the high user I/O is normal due to the Full Table scan in parallel. Query is much faster with parallelization