I have combined instance of piwik with both js tracked sites and log imported sites.
I have set window_look_back_for_visitor = 2678400 so I can track log imported returning visitors, no problem with this it works fine and doesn't cause any performance problem even for such long period.
However it breaks js tracked sites see attached screenshot
using 1.11.1 - is this something to be fixed in 1.12? I cannot run this on production right now.
In fa36f400879eee408a79b6a45443fbec0a48b14a: Adding failing test case showing the bug (visit over several days, creates too many visits) refs #3957
In 9e16d35862ae79c9b006a43193fccdb67e60d89a: This fixture says "14 visits" which is the bug: it should say only "10" visits Refs #3957
In 4f2628fca49047af472f9725b2589392ec3292a7: Fixes #3957 thanks for the report and nice find! The bug was the missing ORDER clause.
Also fixing the "look ahead code" to lookahead at most the visit standard length