Unused point slices are not added back to the pool by the matrix selector

[roganartu]

A recent change to promql/engine.go moved the call to putPointSlice from the evaluator finalizers in the matrixSelector method to elsewhere:

dd6781a#diff-83539908220a826e39b7ba3a4f27d5d6L862

However, now only the used point slices are returned to the pool:

prometheus/promql/engine.go

Line 732 in dd6781a

putPointSlice(s.Points)

I may be missing something here, but afaict unused (ie: empty) point slices should be returned to the pool immediately, since no reference to them is held after the current iteration in matrixSelector anyway.

[juliusv]

@brian-brazil

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.