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My Oracle "imp" processes sleep quite frequently

 
Ravi S. Banda
Regular Advisor

My Oracle "imp" processes sleep quite frequently

I kicked off about 10+ oracle "imp" processes in parallel. Each import process imports one HUGE table at a time. There are no dependencies among them.
I understand processes go to sleep and are swapped out from the run-queue when they are waiting for resources. I also understand that no CPU usage is consumed when out of the run-queue and sleeping.
But, what is the problem?
Sar -Mu 5 5 shows:
14:35:54 cpu %usr %sys %wio %idle
Average 0 34 11 15 40
Average 1 31 12 11 45
Average 2 33 12 9 46
Average 3 32 12 9 47
Average 4 34 12 10 45
Average 5 33 13 10 44
Average 6 36 11 9 45
Average 7 39 12 6 43
Average system 34 12 10 44

sar -d 5 5 shows:
14:37:28 device %busy avque r+w/s blks/s avwait avserv
Average c0t6d0 0.64 0.50 1 18 0.00 7.05
Average c20t0d0 77.11 0.55 721 22052 0.01 1.51

Obviously, c20t0d0 (SAN disk) is showing the maximum activity. But the SAN disk has been created as a LUN from a disk pool / group of multiple disks physically on the EVA5000 disk array. I don't understand. Please help!
4 REPLIES 4
Zdenek Spacek
New Member

Re: My Oracle "imp" processes sleep quite frequently

That's absolutely normal

No CPU cycles are burnt when waiting for I/O to complete. Since you are importing large tables, most of the time your process waits (in sleep mode) for your san to finish reading or writing.
Sandman!
Honored Contributor

Re: My Oracle "imp" processes sleep quite frequently

Even though it most likely is disk I/O but it would help in narrowing down the source of sleeps and waits with the use of glance.
Bill Hassell
Honored Contributor

Re: My Oracle "imp" processes sleep quite frequently

There's nothing to fix. The programs are doing what they were designed to do. What were you expecting?


Bill Hassell, sysadmin
Ravi S. Banda
Regular Advisor

Re: My Oracle "imp" processes sleep quite frequently

Thank you, all. points will be assigned.
-- Ravi.