RE: Web Service slow on first call of the day

["Koester, Michael" <mkoester@xxxxxxxxxxxxx>]

Oops, (I meant that latest reply to go to the folks on the WEB-400 list where I have this cross-posted).

But I was about to offer the same thanks to Nathin and Nadir on this list.

-- Michael

> -----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?