optimize er left join global (#2334)

* optimize er left join global

* optimize er left join global

* fix checkstyle

(cherry picked from commit 2f6b3bf)

Author: PanternBao

dble_checkstyle_suppression.xml

@@ -23,5 +23,5 @@
     <suppress checks=".*" files="BTraceCostTime.java"/>
     <suppress checks="CyclomaticComplexity" files="CreateTableParserImp.java"/>
     <suppress checks="CyclomaticComplexity" files="XMLSchemaLoader.java"/>
-
+    <suppress checks="CyclomaticComplexity" files="GlobalTableProcessor.java"/>
 </suppressions>

src/main/java/com/actiontech/dble/plan/optimizer/ERJoinChooser.java

@@ -77,7 +77,7 @@ public JoinNode optimize() {
      * left join's ER is different from inner join's
      * ex:t1,t2 ,if t1 left join t2 on
      * t1.id=t2.id can be pushed
-     * < we cna't change left join's structure>
+     * < we can't change left join's structure>
      *
      * @return
      */
@@ -107,6 +107,7 @@ private ERTable getLeftOutJoinChildER(JoinNode joinNode, PlanNode child, Item on
             return null;
         else if (!PlanUtil.isERNode(child) && child.type() != PlanNode.PlanNodeType.TABLE)
             return null;
+
         if (onItem == null || !onItem.type().equals(Item.ItemType.FIELD_ITEM))
             return null;
         Pair<TableNode, ItemField> joinColumnInfo = PlanUtil.findColumnInTableLeaf((ItemField) onItem, joinNode);
@@ -130,7 +131,7 @@ else if (!PlanUtil.isERNode(child) && child.type() != PlanNode.PlanNodeType.TABL
     /* ------------------- left join optimizer end -------------------- */
 
     /**
-     * inner join's ER, rebuild inner joi's unit
+     * inner join's ER, rebuild inner join's unit
      *
      * @return
      */
@@ -390,7 +391,8 @@ private void initInnerJoinUnits(JoinNode node) {
     private boolean isUnit(PlanNode node) {
         if (isGlobalTree(node))
             return true;
-        else return node.type() != PlanNode.PlanNodeType.JOIN || node.isWithSubQuery() || !((JoinNode) node).isInnerJoin();
+        else
+            return node.type() != PlanNode.PlanNodeType.JOIN || node.isWithSubQuery() || !((JoinNode) node).isInnerJoin();
     }
 
     /**

src/main/java/com/actiontech/dble/plan/optimizer/GlobalTableProcessor.java

@@ -47,8 +47,7 @@ private static boolean initGlobalStatus(PlanNode tn) {
         if (PlanUtil.isERNode(tn)) {
             // treat er join as an un global table
             tn.setUnGlobalTableCount(1);
-            Set<String> newSet = new HashSet<>();
-            newSet.addAll(tn.getReferedTableNodes().get(0).getNoshardNode());
+            Set<String> newSet = new HashSet<>(tn.getReferedTableNodes().get(0).getNoshardNode());
             tn.setNoshardNode(newSet);
         } else {
             int unGlobalCount = calcUnGlobalCount(tn);
@@ -76,7 +75,9 @@ private static boolean initGlobalStatus(PlanNode tn) {
                     if (left.getUnGlobalTableCount() == 0) { // left node is global,left join will not push down
                         tn.setNoshardNode(null);
                         status = false;
-                    } else if (left.type() == PlanNode.PlanNodeType.TABLE || PlanUtil.isERNode(left)) {
+                    } else if (left.type() == PlanNode.PlanNodeType.TABLE ||
+                            PlanUtil.isERNode(left) ||
+                            left.getNoshardNode() != null && left.getNoshardNode().size() > 0) {
                         if (!isGlobalTableBigEnough(jn)) {
                             tn.setNoshardNode(null);
                             status = false;