Do you need an internal system for collecting visitor statistics, what would you recommend?

Question

PHP

Good afternoon.
Please recommend systems for collecting site visit statistics - an analogue of Yandex.Metrica and Google Analytics.
Requirements: the system must be internal (ala library), or installed in parallel to the observed site.
The system must be running PHP, PostgreSQL and MySQL.
External statistics collection systems are not suitable. I watched Piwik, but it's completely sad with PostgreSQL support.

Answer 1

https://github.com/sri-soham/piwik/blob/master/cor...
It's not so sad... There seems to be something....

Answer 2

Have you looked at OpenStat? Or is it an exclusively fundamental question, so that the data does not go anywhere on the side?
PS.
Just recently I was thinking about writing a system for collecting internal metrics, which are difficult to track through general-purpose metrics. For example: how many clicks were made on a particular product or closing of a certain UI element, how many users won/lost in some kind of random contest, etc.
At what it is possible to fix both in the server logic and through the client part.