more comments

Signed-off-by: Krasi Georgiev <[email protected]>

pkg/query/iter.go

@@ -582,6 +582,7 @@ func (it *dedupSeriesIterator) Next() bool {
 	// Advance both iterators to at least the next highest timestamp plus the potential penalty.
 	if it.aok {
 		it.aok = it.a.Seek(it.lastT + 1 + it.penA)
+		// When A is exhausted the seek for B below should be without any penalty
 		if !it.aok {
 			it.penB = 0
 		}
@@ -615,7 +616,7 @@ func (it *dedupSeriesIterator) Next() bool {
 	it.useA = ta <= tb
 
 	// For the series we didn't pick, add a penalty aligned to the resolution step.
-	// This ensures that we don't miss a sample for the requested step when switching iterators and
+	// This ensures that we don't miss a sample for the requested resolution when switching iterators and
 	// also not pick too many samples for the current resolution.
 	// Promql has a default look back delta of 5min so if the penalty causes the duration
 	// between 2 samples to be greater then the default look back it causes data gaps.