[rt-devel] REST performance drop after upgrade from 4.2.9 to 4.2.10

[Alex Vandiver]

On Tue, 31 Mar 2015 10:58:02 +0200 Christian Loos <cloos at netcologne.de>
wrote:
> Am 30.03.2015 um 19:25 schrieb Alex Vandiver:
> > I'm not aware of any intentional changes in REST between 4.2.9 and
> > 4.2.10 -- which implies that the performance drop is due to
> > second-order changes.
> > 
> > What is the content of the REST request?  If you start up a
> > single-threaded server with Devel::NYTProf on it and make the REST
> > request, where does it say the time is being spent?
> >  - Alex
> 
> I have done this:
> 
> sudo perl -d:NYTProf /opt/rt4/sbin/rt-server --server Standalone --port 8080
> wget http://localhost:8080/REST/1.0/ticket/10587/history?format=l
> nytprofhtml --open
> 
> Attached the nytprofhtml output for
> /opt/rt4/share/html/REST/1.0/Forms/ticket/history
> 
> As I'm not familiar with NYTProf I'm not sure if this is the correct
> output you want.
> If not, it would be great if you can provide details steps to profile
> the REST call.

You've profiled the right thing, but not looked at the correct output
from NYTProf.  Namely, all this says is "7.24s were spent
in /REST/1.0/show".  You'll need to drill down into there to find out
where the time is spent.

Since you're looking for a regression, I suggest you profile both
4.2.10 and 4.2.9 (using the same steps you did above) and explore both
profile outputs in parallel, looking for where the extra 2.5s is coming
from.

As a side note, 100k is pushing what should be sent to rt-devel.  If
you need to share the nytprof outputs, please put the generated HTML
trees on a webserver and provide a link.
 - Alex