Huge discrepancy on reports between 2.12.1 and 2.16.0

Hi all, I’ve been migrating my Piwik instance to a new better spec-ed server. In doing so, I took the opportunity to also upgrade the Piwik from 2.12.1 to 2.16.0 (the latest when I did my setup few weeks ago).

On the first day of switch over, I noticed huge differences in the report. The new version of Piwik (2.16.0) shows much higher stats in general compared to the older one (2.12.1). So much so I need to reverted back to the old version while I am trying to figure out what happened and which one is correct.

To rule out that it is a tracking issue, I set up a test Piwik instances for the two versions, import IIS log for the same day using python import script, and I can confirm that the report generated is very much different. The older version (2.12.1) shows 1,708 visits and the new version (2.16.0) shows 68,504 visits.

Regardless which one is more accurate, what possible technical explanations for this discrepancy. Both two version installed on the same server, imported from the same IIS log file.

If someone could possibly tell me how I could investigate this. Thank you.

Just want to clarify just in case it wasn’t clear in my post above that the stats from live tracking and IIS log import are consistent for the same version of Piwik.

Hi there, maybe an idea: check that both Piwik servers have the same config/config.ini.php in case you have customised some settings which could impact your reports.

Thanks for your response @matthieu

There are some differences but I can’t see how that affecting the stats that much. I attached the diff between two. The left column is the old version and right column is for the newer version.

Let me know if you need anything else.

Hi all, just want to bump this issue … if anyone could offer some feedback as I am really stuck here. Thanks.

I just installed version 2.16.1 and use the same configuration as the one I have for version 2.12.1 and the result is consistent, ie. I have the same result for 2.16.0 and 2.16.1 and that result is greatly different with 2.12.1

If someone could please help. Thanks.

In your reports from 2.12 VS 2.16 where do you notice most differences, is it located in particular page URLs, or maybe particular user configurations? Or do you think the data is tracked less overall?

Do you see any error in your server error log?

Hi @matthieu sorry for late response, I didn’t realise that you responded. The huge difference that I straight away noticed is the number of visits. I don’t see any specific error log.

If you have a small IIS log for test, I don’t mind to run it on both instances and see the difference. And I would like to know which one is closer to your stats. Thanks.