How should I get the values from a Folsom "slide" histogram?

Question

I'm trying out Folsom for metrics generation in Erlang.

I've created a histogram (slide), how can I get the values out of it? I'm using

(test@SebMaynardSL2)1> folsom:start().
(test@SebMaynardSL2)2> MyMetric = "mymetric",
(test@SebMaynardSL2)3> folsom_metrics:new_histogram(MyMetric, slide). 

And tried putting some values in it:

(test@SebMaynardSL2)4> [ folsom_metrics:notify({MyMetric, V}) || V <- lists:seq(1, 10) ].

But getting the values out (with folsom_metrics:get_metric_value/1) seems to be return the results in rather a strange order:

(test@SebMaynardSL2)5> folsom_metrics:get_metric_value(MyMetric).
[4,5,8,9,3,10,2,7,6,1]

If I wait a while (60 seconds, the default slide window time) and do it again, I don't necessarily end up with a metric value in the same order.

How should I get the values out of Folsom to use for (say) graph generation? I did consider putting {now(), V} instead of just V in my notify, and then sorting the returned result set by the first tuple value, but it seems odd that the results are coming back (or rather, are getting written) in a weird order, and Folsom is keeping track of the time of events anyway (to make it "slide").

This is using Folsom 0.7.4, with Erlang R16B

Thanks!

Answer 1

Rather oddly, after a fresh clone and checking out tag 0.7.4 again, running the commands from the question gives the results in the correct order:

(test@SebMaynardSL2)5> folsom_metrics:get_metric_value(MyMetric).
[1,2,3,4,5,6,7,8,9,10]

Perhaps this wasn't an issue after all. No idea why it was generating such oddities the other day.