From a6e010f722d72280ab7bc60bd2ce31290158019b Mon Sep 17 00:00:00 2001
From: minghong <englefly@gmail.com>
Date: Tue, 31 Oct 2023 16:52:17 +0800
Subject: [PATCH] [opt](nereids) use rowcount to compute runtime filter size if
 ndv is not available (#26022)

---
 .../doris/nereids/processor/post/RuntimeFilterGenerator.java   | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterGenerator.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterGenerator.java
index e4ee9d9217..776aa5396f 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterGenerator.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterGenerator.java
@@ -345,7 +345,8 @@ public class RuntimeFilterGenerator extends PlanPostProcessor {
         }
         ExpressionEstimation estimator = new ExpressionEstimation();
         ColumnStatistic buildColStats = compare.right().accept(estimator, right.getStats());
-        return buildColStats.isUnKnown ? -1 : Math.max(1, (long) buildColStats.ndv);
+        return buildColStats.isUnKnown
+                ? Math.max(1, (long) right.getStats().getRowCount()) : Math.max(1, (long) buildColStats.ndv);
     }
 
     public static Slot checkTargetChild(Expression leftChild) {