RE: Web Service slow on first call of the day

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Koester, Michael
Sent: Monday, March 09, 2015 12:16 PM
To: Midrange Systems Technical Discussion
Subject: RE: Web Service slow on first call of the day

Jon, Jim, Henrik, and Brian,
Thanks for your input. I'm hearing from the IWS people that getting the
web service ready to rock is likely where the big impact is. I'll be
looking at adding a "wake-up" web service call to the start-up stack, and
see how much improvement I get with that.
-- Michael

-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of
Nathan Andelin
Sent: Monday, March 09, 2015 11:57 AM
To: Midrange Systems Technical Discussion
Subject: 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?