LabelSet.String sorts incorrectly

[bboreham]

This code:

common/model/labelset.go

Lines 135 to 138 in 1d8c672

	lstrs = append(lstrs, fmt.Sprintf("%s=%q", l, v))
	}
	sort.Strings(lstrs)

will sort foo2="bar" before foo="bar".

The usual sort order of Prometheus labels is alphabetical by names, which would put foo before foo2.

[wasim-nihal]

@bboreham , I would like to work in this issue. Can you please assign this to me?

[bboreham]

Sure, thanks for your interest. It would be good to have a small benchmark, to check that your changes run at about the same speed.