Object cache monitoring what does it monitor?

In our monitoring data we notice a trend where the object cache seems to be increasing since a date last week. What exactly does the object cache monitor and what are the consequences of it being (too) high? EDIT: Thanks Achiel for your explanation, The mendix version we use is 4.5.0. And now that you mention it i do believe that in some versions of Mx 4 the non-persitant objects were not cleared from cache untill they were specifically deleted.
1 answers

It measures the amount of objects (non persistent entities) that are currently 'held' in the runtime. In other words, the objects that are linked to sessions. These obviously use memory, so having too many will result in OOMs.

We heavily recommend upgrading to at least 4.8.6 if you're having object cache issues.