From 755757e57c3dc2029a0cd5a09f1b89ca73d493aa Mon Sep 17 00:00:00 2001
From: minghong <englefly@gmail.com>
Date: Sun, 12 May 2024 18:09:13 +0800
Subject: [PATCH] check pushDownContext validation after
 withNewProbeExpression() (#34704) (#34737)

when the runtime filter target to a constant, the PushDownContext.finalTarget is null.
in this case, do not pushdown runtime filter.
example:
select * from (select 1 as x from T1) T2 join T3 on T2.x=T3.x
when push down RF(T3.x->T2.x) inside "select 1 as x from T1", the column x is a constant, and the pushDown stopped.

(cherry picked from commit 7f06cf0a0125d84c41e1edbb71366e293f70239d)
---
 .../post/RuntimeFilterPushDownVisitor.java    | 19 +++++++++++++++----
 1 file changed, 15 insertions(+), 4 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterPushDownVisitor.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterPushDownVisitor.java
index f268d1ab8b..7cadbde176 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterPushDownVisitor.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/processor/post/RuntimeFilterPushDownVisitor.java
@@ -103,9 +103,14 @@ public class RuntimeFilterPushDownVisitor extends PlanVisitor<Boolean, PushDownC
             this.exprOrder = exprOrder;
             this.isNot = isNot;
             Expression expr = getSingleNumericSlotOrExpressionCoveredByCast(probeExpr);
+            /* finalTarget can be null if it is not a column from base table.
+            for example:
+            select * from T1 join (select 9 as x) T2 on T1.x=T2.x,
+            where the final target of T2.x is a constant
+            */
             if (expr instanceof Slot) {
                 probeSlot = (Slot) expr;
-                finalTarget = rfContext.getAliasTransferPair((Slot) probeSlot);
+                finalTarget = rfContext.getAliasTransferPair(probeSlot);
             } else {
                 finalTarget = null;
                 probeSlot = null;
@@ -289,6 +294,9 @@ public class RuntimeFilterPushDownVisitor extends PlanVisitor<Boolean, PushDownC
         }
         for (Expression prob : probExprList) {
             PushDownContext ctxForChild = prob.equals(ctx.probeExpr) ? ctx : ctx.withNewProbeExpression(prob);
+            if (!ctxForChild.isValid()) {
+                continue;
+            }
             if (ctx.rfContext.isRelationUseByPlan(leftNode, ctxForChild.finalTarget.first)) {
                 pushed |= leftNode.accept(this, ctxForChild);
             }
@@ -363,8 +371,11 @@ public class RuntimeFilterPushDownVisitor extends PlanVisitor<Boolean, PushDownC
                 }
             }
         }
-
-        return project.child().accept(this, ctxProjectProbeExpr);
+        if (!ctxProjectProbeExpr.isValid()) {
+            return false;
+        } else {
+            return project.child().accept(this, ctxProjectProbeExpr);
+        }
     }
 
     @Override
@@ -401,7 +412,7 @@ public class RuntimeFilterPushDownVisitor extends PlanVisitor<Boolean, PushDownC
                  *   +--->select 0, 0
                  * push down context for "select 0, 0" is invalid
                  */
-                pushedDown |= setOperation.child(i).accept(this, ctx.withNewProbeExpression(newProbeExpr));
+                pushedDown |= setOperation.child(i).accept(this, childPushDownContext);
             }
         }
         return pushedDown;