diff --git a/aw-query/src/functions.rs b/aw-query/src/functions.rs
index 53e7d9bb..c060b9a6 100644
--- a/aw-query/src/functions.rs
+++ b/aw-query/src/functions.rs
@@ -506,7 +506,7 @@ mod qfunctions {
         let events: Vec<Event> = (&args[0]).try_into()?;
         let filter_events: Vec<Event> = (&args[1]).try_into()?;
 
-        let mut filtered_events = aw_transform::filter_period_intersect(&events, &filter_events);
+        let mut filtered_events = aw_transform::filter_period_intersect(events, filter_events);
         let mut filtered_tagged_events = Vec::new();
         for event in filtered_events.drain(..) {
             filtered_tagged_events.push(DataType::Event(event));
diff --git a/aw-transform/benches/bench.rs b/aw-transform/benches/bench.rs
index 443f7ba3..0631e67c 100644
--- a/aw-transform/benches/bench.rs
+++ b/aw-transform/benches/bench.rs
@@ -45,7 +45,7 @@ fn bench_filter_period_intersect(c: &mut Criterion) {
     c.bench_function("1000 events", |b| {
         b.iter(|| {
             let events1 = create_events(1000);
-            filter_period_intersect(&events1, &events2);
+            filter_period_intersect(events1, events2.clone());
         })
     });
 }
diff --git a/aw-transform/src/filter_period.rs b/aw-transform/src/filter_period.rs
index 15781da2..cd8f4366 100644
--- a/aw-transform/src/filter_period.rs
+++ b/aw-transform/src/filter_period.rs
@@ -32,7 +32,6 @@ pub fn filter_period_intersect(events: Vec<Event>, filter_events: Vec<Event>) ->
     let mut cur_filter_event = filter_events_iter.next().unwrap();
 
     loop {
-        // TODO: what about duration = 0?
         let event_endtime = cur_event.calculate_endtime();
         let filter_endtime = cur_filter_event.calculate_endtime();
         if cur_event.duration == Duration::seconds(0) || event_endtime <= cur_filter_event.timestamp {