I implemented this feature and it reduces number of entries of StatisticsList. I decided to skip shrinking of other statistics as they are rather small in size (single entry there is int, long of float).

By default statistics history cache will be reduced if memory is used in more than 95% - this can be changed by stats-high-memory-level property of stats component which is @int@.

Reduction will take place when next entry is added to cache when there is more memory used than specified. Half of existing entries will be removed. If during next addition of item same thing will occur then half of left entries will be removed. I set minimal number of entries in this cache to 5, so there should be at least 5 last entries.

Tested and confirm it works as expected;

Daniel, can you add information about new feature and config option to the 7.2.0 documentation in master branch?

stats/stats-high-memory-level[I]=95