From e9b64c4f793e069b5754eae1e7d9d3ed00201c73 Mon Sep 17 00:00:00 2001
From: "zhongjian.xzj" <zhongjian.xzj@zhongjianxzjdeMacBook-Pro.local>
Date: Wed, 11 Sep 2024 21:24:38 +0800
Subject: [PATCH] [opt](nereids) refine expression estimation

---
 .../java/org/apache/doris/nereids/stats/FilterEstimation.java  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java
index a65a07fea30bdfc..a03c8d1ce7e9e9b 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java
@@ -332,7 +332,8 @@ private Statistics estimateEqualTo(ComparisonPredicate cp, ColumnStatistic stats
             } else {
                 double val = statsForRight.maxValue;
                 if (val > statsForLeft.maxValue || val < statsForLeft.minValue) {
-                    selectivity = 0.0;
+                    // do a lower bound protection to avoid using 0 directly
+                    selectivity = RANGE_SELECTIVITY_THRESHOLD;
                 } else if (ndv >= 1.0) {
                     selectivity = StatsMathUtil.minNonNaN(1.0, 1.0 / ndv);
                 } else {