I have been running piwik for two years now we are pretty happy with it but I recently noticed something was wrong with our segments data. We have a few dozens of segments and it appears that pages count, visit counts, etc. are wrong. For example, we have that segment that used to hit around 90k visits a month and since july the numers are now as low as 200 visits.
I know those numbers are wrong because if I look at the number of visits or pageviews for one url inside the segment and compare it with the same url on the default “all the visits” segment, it appears that the page gets more visits on the “all visits” segment than the total of the visits for the whole segment.
I know you’ll tell me maybe most of the view for that page is made in a different context than the segment you set up. Actually it might be true for a tiny percentage of the visits, but I doublechecked by analysing my piwik’s server apache’s logs and when piwik says there was only 200 pagesviews in my segment during last month, I can find more than 1000 calls to piwik.php coming from that page with the proper segment data every day of the past month.
I also set up a Google Analytics account and set up the same segment and the data is conform with what we were expecting. For example, for that big segment, we got 88K visits in september according to GA and…234 according piwik.
Whatever happened (did I change something in my tracking code, configuration, did an upgrade break something?) it must have happened either at the end of june or first week of july since since then all the segments lost their coherence.
What I don’t really understand is why I still have a few visits in my segments. If something went wrong with my tracker code or whatever, I would have rather expected the segments to be empty instead of still getting a few hits. Why those hits are still accounted when 99.99% are just lost… weird.
Do anyone have an idea of what could have gone wrong?