Are histogram memory sizes bounded practically?

[thvasilo]

By keeping the number of bins constant we ensure that the size of the histograms in memory is bounded, theoretically.

I did some investigation by inserting 100k values into a few histograms and got their average size in memory using sizeof.

I've included the results below, which show a small positive trend as we continue adding values,
after all the bins (using 100 here) have been populated.

Is this expected behavior? Is there a way to impose a hard limit on the size of the histograms in memory?