Thank you! But I am thinking, could I be able to obtain easily the duration of each meeting using this setup? This is what I would ultimately need (to construct the empirical cdf, social network, etc.)
It's not like you're ingesting gobs and gobs of data in real time :)
There are four types of meeting: mouse 1 entered -> mouse 2 entered -> mouse 2 left -> mouse 1 left; mouse 1 entered -> mouse 2 entered -> mouse 1 left -> mouse 2 left; mouse 2 entered -> mouse 1 entered -> mouse 1 left -> mouse 2 left; mouse 2 entered -> mouse 1 entered -> mouse 2 left -> mouse 1 left.
Then the meeting record contains the times the two were together and the duration of this.
The dumb approach is very slow. Would it be a good idea to read all stay results in Scala (or whatever) and try to do the searching in memory, completely eliminating th db? But then the comparisons would be more expensive...