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NASCAR9 · Posted: Mon Oct 19, 2009 12:23 pm Post subject: zIIP Processing

I'm looking for real world experiences with zIIP engines. We currently have one in house and I'm trying to exploit it. This leads me to my questions.

1. Does it make sense to offload very fast stored procedures that execute 1000's of times to the zIIP? This would free the main CPU for other things.

2. Do you only offload longer running (4 seconds or more) stored procedures to the zIIP?

3. Other suggestions.
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NASCAR9

kolusu · Posted: Mon Oct 19, 2009 12:47 pm Post subject:

NASCAR9,

AFAIK, A stored procedure arrives as an enclave via the DDF address space and switches to TCB mode when it runs in the stored procedure address space. The Stored procedure is processed by the DBM1 address space like any other SQL statement and will remain in enclave mode. Since it runs as an enclave, it becomes zIIP eligible. The percentage of work eligibility is dependent on the amount of SQL in the stored procedure.

Kolusu

vmbigot · Posted: Mon Oct 19, 2009 1:29 pm Post subject:

Kolusu,

Pardon me for jumping in on this thread. NASCAR9 and I work in the same shop, so I have a vested interest in anything that he does. You stated that the amount of SQL in the native stored procedure determines how much is zIIP eligible. Is stored procedure logic (if-then-else) eligible or is it just the SQL that is eligible?

vmbigot
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kolusu · Posted: Tue Oct 20, 2009 11:39 am Post subject:

vmbigot,

Honestly I am not sure but from what I read is that only SQL's/Call statement processing/Result processing/Commit processing are eligible for zIIP.

Remember that WLM managed stored procedures are NOT eligible for zIIP

Remote Native SQL procedures which run enclave SRB, are zIIP eligible

Kolusu

vmbigot · Posted: Tue Oct 20, 2009 12:20 pm Post subject:

Kolusu,

I read the same thing and am gratified that I had read it correctly. My suspicion is that the DBM1 address space executes the logic in a native stored procedure as a TCB and the SQL as an enclave SRB. I wonder if it would be better (i.e. more efficient) to run a stored procedure that has heavy logic and little SQL as a WLM managed stored procedure instead of native? This would free up the DBM1 address space to do real SQL (and zIIP eligible) work. What's your take on this? Or then again, maybe I am over analyzing this and should let the operating system do it's job.

vmbigot
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Inside every older man is a young boy asking this question. What the heck happened?!?

NASCAR9 · Posted: Wed Oct 21, 2009 1:53 pm Post subject:

Thanks for your responses Kolusu and vmbigot!

Doesn't anyone else use a zIIP engine? Question

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NASCAR9