Re: Web Service slow on first call of the day

Michael,

"Choke point" is the right "catch phrase" in this case. No bottle-neck. The
environment just takes time to initialize after a shut-down. Odds are that
the Java environment is taking the most time to initialize, though the SQL
environment may be a factor. I'd suggest automating the first request to
your web service by using an HTTPAPI when you bring up your subsystems.

.



On Mon, Mar 9, 2015 at 9:38 AM, Koester, Michael <mkoester@xxxxxxxxxxxxx>
wrote:

It's possible, Dana.
Perhaps to test that I can just call the program the web service would run
and then execute the first web service call of the day after that. That
might blaze the trail for the web service to follow.
The SQL is not all that complex, but there are a fair number of Select
Into statements and a few INSERT statements (activity logging) that occur.
If I do that, and see no significant improvement for that first web service
call, that would suggest that there might be an obstacle in the
communications (HTTP server) department.
If I can at least understand what the choke-point is, I can see what might
be done to "prime" the right pump.
Thanks.

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Mitchell, Dana
Sent: Monday, March 09, 2015 10:51 AM
To: Midrange Systems Technical Discussion
Subject: RE: Web Service slow on first call of the day

Michael,

We experienced (and actually still are) something like this. The
application in question is an ODBC call to very large complex SQL
commands. After applying maintenance, coming up to current cumulative
and group levels, we experienced a drastic increase in CPU usage for
these queries. According to IBM, the increased time is spent in Plan
Selection, in our case using multiple minutes of CPU time. Then once
through the selection, the queries run in sub second response time like
they did before the maintenance was applied.

Does this sound like your scenario at all?

Dana

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Koester, Michael
Sent: Monday, March 09, 2015 7:59 AM
To: midrange-l@xxxxxxxxxxxx
Subject: Web Service slow on first call of the day

(cross-posting to WEB-400)
I have developed a web service with the Integrated Web Services facility
(IWS) that is almost production ready, but I'm noticing that the very
first call of the day takes 30-45 seconds to return a response. A
subsequent calls provide sub-second responses, and that continues
throughout the day. I'm normally pretty patient, but this will be used

to

provide data to a customer-facing web site, and if I was the first
customer of the day to the web site, I'd give up if it hung for more than
10 seconds -- by 30 seconds I'd be off doing other things for sure.

My questions are:
1. What are the likely causes for the delay-on-first-call behavior?
2. What might I do to either eliminate the problem, or perhaps simulate a
call on web server start-up, so that the first customer gets an

acceptable

response time?



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