From aad8043d44ef7b9aa860905d99f197616cc2a92a Mon Sep 17 00:00:00 2001
From: morrySnow <101034200+morrySnow@users.noreply.github.com>
Date: Sat, 8 Jul 2023 21:47:17 +0800
Subject: [PATCH] [opt](Nereids) enable parallel scan for local phase agg
 (#21642)

after we forbid some cases off agg candidate plans,
all local phase agg require DistributionSpecAny for child.
So, we could enable parallel scan for it
---
 .../nereids/glue/translator/PhysicalPlanTranslator.java      | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java
index 9844179633..fb01db5c41 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/glue/translator/PhysicalPlanTranslator.java
@@ -699,8 +699,11 @@ public class PhysicalPlanTranslator extends DefaultPlanVisitor<PlanFragment, Pla
         // TODO: nereids forbid all parallel scan under aggregate temporary, because nereids could generate
         //  so complex aggregate plan than legacy planner, and should add forbid parallel scan hint when
         //  generate physical aggregate plan.
+        //  There is one exception, we use some precondition in optimizer, input to buffer always require any for input,
+        //  so when agg mode is INPUT_TO_BUFFER, we do not forbid parallel scan
         if (leftMostNode instanceof OlapScanNode
-                && inputPlanFragment.getDataPartition().getType() != TPartitionType.RANDOM) {
+                && inputPlanFragment.getDataPartition().getType() != TPartitionType.RANDOM
+                && aggregate.getAggregateParam().aggMode != AggMode.INPUT_TO_BUFFER) {
             inputPlanFragment.setHasColocatePlanNode(true);
         }
         setPlanRoot(inputPlanFragment, aggregationNode, aggregate);