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Why is DT showing our webservers as having a very long execute time?

jkinny
Guide

I recently installed the webserver agent on some of our Apache webservers. Some transactions that in the past would only take ~2 seconds are now showing as >60s, with all of the execute time happening in the webserver, after the appserver has finished its work. I've attached screenshots below. The application owner and webserver owner are saying that there is no way that is showing the true time. My question(s), have I set something up incorrectly? Is there a bug in DT? OR how can I can look in DT to show them that something in the webserver is indeed taking that long?

8 REPLIES 8

pahofmann
Leader

The time you are looking at is exec total, this is the total time in this web request, so as it is the root node of the PurePath this is the total time of this purepath including all other calls and executions.

So this time is not only in the web server. have a look at the API Breakdown or Transaction Flow at the bottom of the PurePath Dashboard to get a better grasp on where the time is spend in this PurePath.

So in the above screenshot I collapsed the pure path once it hits the appserver since there was not much going on past there. If you take a look at the exec total for the appserver tier execution (there's only the 1 twisty there) it is only ~1.9s. I actually opened up the API Breakdown like you suggested and saw this:

Could you make another screenshot of the PurePath Tree where the "elapsed time" column is visible? It may be that the time in the webserver is in native modules in the web server.

Sure, it's a pretty long tree, so here's the very bottom of the appserver thread above. Keep in mind that this all stems from 1 appserver execution so I don't think we're missing a bunch of appserver executions that all add up to 70s.

To me it almost seems like the webserver timer keeps going, even though the appserver has finished what it's doing in the first 2 seconds.

Actually the top of the PurePath would be of interest here. As I said, it could be time spend in a native module of the web server, you would see that in the diference of elapsed time when the call is passed to the app server.

As of 6.5 there is no way to get insights into the native modules, so the time would not be listed in the API breakdown or PurePath tree. With appmon version 7 there is now a sensor pack for apache/nginx modules.

Sorry about there, here's the top and I've made a mark where it should switch over. Also that is interesting about appmon7, I may have to try that out since other than time, I don't have much insight into the webserver:

Yes that is fine, so not a problem with a native module.

Any relevant infos in the web request details (right click -> Details)? Maybe you could add a export of the PurePath?

Nothing weird to me other than that it seems to be a spider of some kind: