What does ClientCancel mean in the HTTPERR log

In our IIS log files, I noticed on occasion there are pageviews missing. Further investigating this issue I took a look at the %systemroot%\System32\LogFiles\HTTPERR log files. Here I found that the pageviews missing have a 'ClientCancel' message. Below a brief example:

#Software: Microsoft HTTP API 2.0
#Version: 1.0
#Date: 2021-02-21 05:07:18
#Fields: date time c-ip c-port s-ip s-port cs-version cs-method cs-uri streamid sc-status s-siteid s-reason s-queuename
2021-02-21 11:32:07 **.***.**.** 22251 ***.***.***.*** 443 - - - - - - ClientCancel -

Strangely in google analytics, this pageview is tracked. Does this mean in the case of ClientCancel the page can already be partially sent to the client and partially rendered by the client's browser?

I am not quite sure what to make of this any help will be appreciated!

Solution 1:

I think you pretty much sum it up. Processing was stopped due to client side cancelling.

OTOH google analytics tracks - well, that depends where you implemented it, but possibly on the top of the page, so a page that gets stopped halfway through may be tracked as page view.

There is not a lot you can do about it. Just eat a certain percentages as normal loss. Measuring client/server operations are tricky, and sometimes the view of different measurements are different in the details.