Checking performance with Add Sense Chrome extension

One of the uses for the Add Sense Chrome extension is to check performance in your Qlik Sense app or mashup. To help you with this the info boxes show you a few numbers, collected as you use the extension. When you select to show the boxes, it will start collecting statistics, and you will se something like this:

Initial display with no values calculated

In this post I am using one of Qliks demo apps (you find it here, try it yourself!), so I don’t really expect to find any performance problems.

The Chrome extension will find all both objects defined in the app and session objects, but only ones that are shown on the page. For all such objects it will start collecting statistics:

  • number of recalculations made
  • latest calculation time in milliseconds
  • maximum calculation time

In the top left corner you will see the handle, that’s a number that the QIX Engine assigns to objects as they are opened. If you want to see the actual messages sent for a specific object in the web socket log you need this number. Since the handles are assigned in sequence, you will also get a grip of how many objects you are using in your solution.

Now to try this lets make some selection. Open the selection tool and click on show in the extension menu (yes the extension works in the selection tool too).Make some selections and you will see something like this (excuse me, it’s in swedish):

Selection tool with the Chrome extension enabled

Confirm your selections and close the selection tool. When you come back to the sheet probably only the app infobox will be visible. When Qlik Sense removes the objects from the page, the infoboxes disappear too. But the extension will continue to collect statistics, so click on show again in the extension menu, and you will se something like this:

Calculations have been made

Note that objects have only been recalculated once. That’s because the client only recalculate objects that are visible on the screen. The text object on the left should not be recalculated at all, since it was not affected by our selections.

So that’s what you need to do in a real situation:

  1. enable timing for objects on the screen with the show command
  2. make your selections, the extension wil register recalculations
  3. if objects have been off screen, reenable the infoboxes with the show command
  4. analyze the figures. Look for long calculation times or too many recalculations

Once you have started the timing, the only way to stop it is by refreshing the page, using the show command will not stop the monitoring.

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