refine comment

Signed-off-by: Richard Chien <stdrc@outlook.com>
risingwavelabs · Apr 19, 2023 · 773aa63 · 773aa63
1 parent 94c7559
commit 773aa63
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/src/stream/src/executor/over_window/state/buffer.rs b/src/stream/src/executor/over_window/state/buffer.rs
@@ -33,6 +33,12 @@ pub(super) struct WindowBuffer<K: Ord, V> {
 
 const LEFT_IDX: usize = 0;
 
+/// Two simple properties of a window frame:
+/// 1. If the following half of the window is saturated, the current window is ready.
+/// 2. If the preceding half of the window is saturated, the first several entries can be removed
+/// when sliding.
+///
+/// Note: A window frame can be pure preceding, pure following, or across the _current row_.
 pub(super) struct CurrWindow<'a, K> {
     pub key: Option<&'a K>,
     pub preceding_saturated: bool,