From aa67d02543b1af583c997ffd9b5bd7e3c1c6191d Mon Sep 17 00:00:00 2001
From: PHILO-HE <feilong.he@intel.com>
Date: Tue, 10 Dec 2024 15:28:02 +0800
Subject: [PATCH] Opt following logic

---
 velox/exec/WindowPartition.cpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/velox/exec/WindowPartition.cpp b/velox/exec/WindowPartition.cpp
index 2c75661c75d0..19f33812ed54 100644
--- a/velox/exec/WindowPartition.cpp
+++ b/velox/exec/WindowPartition.cpp
@@ -437,7 +437,21 @@ void WindowPartition::updateKRangeFrameBounds(
       } else {
         // start = lastFoundIndex == -1 ? currentRow
         //                              : std::min(lastFoundIndex, numRows - 1);
-        start = currentRow;
+        if (i == 0) {
+          start = currentRow;
+        } else {
+          auto compareResult = data_->compare(
+              partition_[currentRow - 1],
+              partition_[currentRow],
+              mappedFrameColumn,
+              mappedFrameColumn,
+              flags);
+          if (compareResult <= 0) {
+            start = lastFoundIndex == -1 ? currentRow : lastFoundIndex;
+          } else {
+            start = currentRow;
+          }
+        }
         end = partition_.size();
       }
       rawFrameBounds[i] = searchFrameValue(