From 1ba473ac4645bb9c6c0aa369ed77f7603afcdce9 Mon Sep 17 00:00:00 2001
From: wenyh <44251917+wenyh1@users.noreply.github.com>
Date: Mon, 14 Mar 2022 16:39:32 +0800
Subject: [PATCH] [inner-1674] fix: nestloop scenarios's bug (#3172)

---
 .../nio/handler/builder/HandlerBuilder.java    | 18 ++++++++++++++----
 .../dble/server/handler/ExplainHandler.java    | 17 ++++++++++++++++-
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/actiontech/dble/backend/mysql/nio/handler/builder/HandlerBuilder.java b/src/main/java/com/actiontech/dble/backend/mysql/nio/handler/builder/HandlerBuilder.java
index d0f5b23d3..beaa3f2da 100644
--- a/src/main/java/com/actiontech/dble/backend/mysql/nio/handler/builder/HandlerBuilder.java
+++ b/src/main/java/com/actiontech/dble/backend/mysql/nio/handler/builder/HandlerBuilder.java
@@ -7,9 +7,7 @@ package com.actiontech.dble.backend.mysql.nio.handler.builder;
 
 import com.actiontech.dble.backend.mysql.nio.handler.builder.sqlvisitor.GlobalVisitor;
 import com.actiontech.dble.backend.mysql.nio.handler.query.DMLResponseHandler;
-import com.actiontech.dble.backend.mysql.nio.handler.query.impl.BaseSelectHandler;
-import com.actiontech.dble.backend.mysql.nio.handler.query.impl.MultiNodeEasyMergeHandler;
-import com.actiontech.dble.backend.mysql.nio.handler.query.impl.MultiNodeMergeHandler;
+import com.actiontech.dble.backend.mysql.nio.handler.query.impl.*;
 import com.actiontech.dble.plan.node.*;
 import com.actiontech.dble.route.RouteResultsetNode;
 import com.actiontech.dble.route.util.RouterUtil;
@@ -111,10 +109,22 @@ public class HandlerBuilder {
         return null;
     }
 
+    public boolean canAsWholeToSingle(List<DMLResponseHandler> merges) {
+        if (merges.size() != 1)
+            return false;
+        DMLResponseHandler next = merges.get(0).getNextHandler();
+        while (next != null) {
+            if (next instanceof TempTableHandler || next instanceof DelayTableHandler)
+                return false;
+            next = next.getNextHandler();
+        }
+        return true;
+    }
+
     // check whether the SQL can be directly sent to a single node
     private RouteResultsetNode getTryRouteSingleNode(BaseHandlerBuilder builder, boolean isHaveHintPlan2Inner) {
         RouteResultsetNode routeNode = null;
-        if (builder.getEndHandler().getMerges().size() == 1 && builder.getSubQueryBuilderList().size() == 0) {
+        if (canAsWholeToSingle(builder.getEndHandler().getMerges()) && builder.getSubQueryBuilderList().size() == 0) {
             RouteResultsetNode[] routes = ((MultiNodeMergeHandler) (builder.getEndHandler().getMerges().get(0))).getRoute();
             if (routes.length == 1) {
                 routeNode = routes[0];
diff --git a/src/main/java/com/actiontech/dble/server/handler/ExplainHandler.java b/src/main/java/com/actiontech/dble/server/handler/ExplainHandler.java
index f8ab8a4c4..fc5be1f6e 100644
--- a/src/main/java/com/actiontech/dble/server/handler/ExplainHandler.java
+++ b/src/main/java/com/actiontech/dble/server/handler/ExplainHandler.java
@@ -10,7 +10,10 @@ import com.actiontech.dble.backend.mysql.PacketUtil;
 import com.actiontech.dble.backend.mysql.nio.handler.builder.BaseHandlerBuilder;
 import com.actiontech.dble.backend.mysql.nio.handler.builder.HandlerBuilder;
 import com.actiontech.dble.backend.mysql.nio.handler.builder.sqlvisitor.GlobalVisitor;
+import com.actiontech.dble.backend.mysql.nio.handler.query.DMLResponseHandler;
+import com.actiontech.dble.backend.mysql.nio.handler.query.impl.DelayTableHandler;
 import com.actiontech.dble.backend.mysql.nio.handler.query.impl.MultiNodeMergeHandler;
+import com.actiontech.dble.backend.mysql.nio.handler.query.impl.TempTableHandler;
 import com.actiontech.dble.config.ErrorCode;
 import com.actiontech.dble.config.Fields;
 import com.actiontech.dble.config.model.sharding.SchemaConfig;
@@ -202,10 +205,22 @@ public final class ExplainHandler {
         return false;
     }
 
+    public static boolean canAsWholeToSingle(List<DMLResponseHandler> merges) {
+        if (merges.size() != 1)
+            return false;
+        DMLResponseHandler next = merges.get(0).getNextHandler();
+        while (next != null) {
+            if (next instanceof TempTableHandler || next instanceof DelayTableHandler)
+                return false;
+            next = next.getNextHandler();
+        }
+        return true;
+    }
+
     // check whether the SQL can be directly sent to a single node
     private static RouteResultsetNode getTryRouteSingleNode(BaseHandlerBuilder builder, RouteResultset rrs) {
         RouteResultsetNode routeNode = null;
-        if (builder.getEndHandler().getMerges().size() == 1 && builder.getSubQueryBuilderList().size() == 0) {
+        if (canAsWholeToSingle(builder.getEndHandler().getMerges()) && builder.getSubQueryBuilderList().size() == 0) {
             RouteResultsetNode[] routes = ((MultiNodeMergeHandler) (builder.getEndHandler().getMerges().get(0))).getRoute();
             if (routes.length == 1) {
                 routeNode = routes[0];