Fix query push down and add subquery handling

src/sql/resolver/dml/ob_dml_stmt.cpp

@@ -3084,6 +3084,23 @@ bool ObDMLStmt::has_link_table() const
   return bret;
 }
 
+int ObDMLStmt::get_table_rel_ids(const TableItem &target,
+                                 ObSqlBitSet<> &table_set) const
+{
+  int ret = OB_SUCCESS;
+  if (target.is_joined_table()) {
+    const JoinedTable &cur_table = static_cast<const JoinedTable &>(target);
+    for (int64_t i = 0; OB_SUCC(ret) && i < cur_table.single_table_ids_.count(); ++i) {
+      if (OB_FAIL(table_set.add_member(get_table_bit_index(cur_table.single_table_ids_.at(i))))) {
+        LOG_WARN("failed to add member", K(ret), K(cur_table.single_table_ids_.at(i)));
+      }
+    }
+  } else if (OB_FAIL(table_set.add_member(get_table_bit_index(target.table_id_)))) {
+    LOG_WARN("failed to add member", K(ret), K(target.table_id_));
+  }
+  return ret;
+}
+
 int ObDMLStmt::get_relation_exprs(ObIArray<ObRawExpr*>& rel_array, int32_t ignore_scope /* = 0*/) const
 {
   int ret = OB_SUCCESS;

src/sql/resolver/dml/ob_dml_stmt.h

@@ -887,6 +887,7 @@ public:
   virtual int clear_sharable_expr_reference();
   virtual int get_from_subquery_stmts(common::ObIArray<ObSelectStmt*>& child_stmts) const;
   int is_referred_by_partitioning_expr(const ObRawExpr* expr, bool& is_referred);
+  int get_table_rel_ids(const TableItem &target, ObSqlBitSet<> &table_set) const;
   int64_t get_table_size() const
   {
     return table_items_.count();

src/sql/rewrite/ob_transform_query_push_down.cpp

@@ -342,6 +342,10 @@ int ObTransformQueryPushDown::check_select_item_push_down(ObSelectStmt* select_s
   if (OB_ISNULL(select_stmt) || OB_ISNULL(view_stmt)) {
     ret = OB_INVALID_ARGUMENT;
     LOG_WARN("stmt is NULL", K(select_stmt), K(view_stmt), K(ret));
+  } else if (OB_FAIL(check_select_item_subquery(*select_stmt, *view_stmt, check_status))) {
+    LOG_WARN("failed to check select item has subquery", K(ret));
+  } else if (!check_status) {
+    can_be = false;  
   } else if (view_stmt->is_contains_assignment() || select_stmt->is_contains_assignment()) {
     can_be = false;
   } else if (OB_FAIL(is_select_item_same(select_stmt, view_stmt, check_status, select_offset, const_select_items))) {
@@ -358,6 +362,58 @@ int ObTransformQueryPushDown::check_select_item_push_down(ObSelectStmt* select_s
   return ret;
 }
 
+int ObTransformQueryPushDown::check_select_item_subquery(ObSelectStmt &select_stmt,
+                                                         ObSelectStmt &view,
+                                                         bool &can_be)
+{
+  int ret = OB_SUCCESS;
+  can_be = true;
+  ObSEArray<ObRawExpr*, 4> column_exprs_from_subquery;
+  ObRawExpr *expr = NULL;
+  TableItem *table = NULL;
+  ObSqlBitSet<> table_set;
+  if (OB_UNLIKELY(1 != select_stmt.get_table_items().count())
+      || OB_ISNULL(table = select_stmt.get_table_item(0))) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("unexpect select stmt", K(ret), K(select_stmt.get_from_item_size()), K(table));
+  }
+  for (int64_t i = 0; OB_SUCC(ret) && i < view.get_select_item_size(); ++i) {
+    if (OB_ISNULL(expr = view.get_select_item(i).expr_)) {
+      ret = OB_ERR_UNEXPECTED;
+      LOG_WARN("unexpect null expr", K(ret));
+    } else if (!expr->has_flag(CNT_SUB_QUERY)) {
+      /* do nothing */
+    } else if (OB_ISNULL(expr = select_stmt.get_column_expr_by_id(table->table_id_,
+                                                                  i + OB_APP_MIN_COLUMN_ID))) {
+      /* do nothing */
+    } else if (OB_FAIL(column_exprs_from_subquery.push_back(expr))) {
+      LOG_WARN("failed to push back column expr", K(ret));
+    }
+  }
+  if (OB_FAIL(ret)) {
+  } else if (column_exprs_from_subquery.empty()) {
+    /* do nothing */
+  } else if (OB_FAIL(select_stmt.get_table_rel_ids(*table, table_set))) {
+    LOG_WARN("failed to get rel ids", K(ret));
+  } else {
+    ObIArray<ObQueryRefRawExpr*> &subquery_exprs = select_stmt.get_subquery_exprs();
+    ObSEArray<ObDMLStmt *, 4> ignore_stmts;
+    ObSEArray<ObRawExpr*, 4> column_exprs;
+    for (int64_t i = 0; OB_SUCC(ret) && can_be && i < subquery_exprs.count(); ++i) {
+      column_exprs.reuse();
+      if(OB_FAIL(ObTransformUtils::extract_column_exprs(subquery_exprs.at(i),
+                                                        select_stmt.get_current_level(),
+                                                        table_set, ignore_stmts,
+                                                        column_exprs))) {
+        LOG_WARN("extract column exprs failed", K(ret));
+      } else if (ObOptimizerUtil::overlap(column_exprs, column_exprs_from_subquery)) {
+        can_be = false;
+      }
+    }
+  }
+  return ret;
+}
+
 int ObTransformQueryPushDown::check_where_condition_push_down(
     ObSelectStmt* select_stmt, ObSelectStmt* view_stmt, bool& transform_having, bool& can_be)
 {

src/sql/rewrite/ob_transform_query_push_down.h

@@ -56,7 +56,9 @@ private:
   int check_select_item_push_down(ObSelectStmt* select_stmt, ObSelectStmt* view_stmt,
       common::ObIArray<int64_t>& select_offset, common::ObIArray<SelectItem>& const_select_items, bool& can_be);
 
-  int check_select_item_has_subquery(ObSelectStmt& view, bool& has);
+  int check_select_item_subquery(ObSelectStmt &select_stmt,
+                                 ObSelectStmt &view,
+                                 bool &can_be);
 
   int adjust_stmt_hints(ObSelectStmt* select_stmt, ObSelectStmt* view_stmt);
 

src/sql/rewrite/ob_transform_utils.cpp

@@ -4594,6 +4594,7 @@ int ObTransformUtils::extract_column_exprs(ObDMLStmt* stmt, const int64_t stmt_l
 {
   int ret = OB_SUCCESS;
   ObSEArray<ObRawExpr*, 16> relation_exprs;
+  ObSEArray<ObSelectStmt*, 16> child_stmts;
   bool is_stack_overflow = false;
   if (OB_ISNULL(stmt)) {
     ret = OB_ERR_UNEXPECTED;
@@ -4609,7 +4610,19 @@ int ObTransformUtils::extract_column_exprs(ObDMLStmt* stmt, const int64_t stmt_l
     LOG_WARN("failed to get relation exprs", K(ret));
   } else if (OB_FAIL(SMART_CALL(extract_column_exprs(relation_exprs, stmt_level, table_set, ignore_stmts, columns)))) {
     LOG_WARN("failed to extract column exprs", K(ret));
-  } else { /*do nothing*/
+  } else if (OB_FAIL(stmt->get_from_subquery_stmts(child_stmts))) {
+    LOG_WARN("get child stmt failed", K(ret));  
+  } else {
+    for (int64_t i = 0; OB_SUCC(ret) && i < child_stmts.count(); ++i) {
+      ObSelectStmt* child_stmt = child_stmts.at(i);
+      if (OB_ISNULL(child_stmt)) {
+        ret = OB_ERR_UNEXPECTED;
+        LOG_WARN("invalid stmt", K(ret));
+      } else if (OB_FAIL(SMART_CALL(extract_column_exprs(child_stmt, stmt_level, table_set,
+                                                          ignore_stmts, columns)))) {
+        LOG_WARN("failed to extract column exprs", K(ret));
+      }
+    }
   }
   return ret;
 }
@@ -6545,7 +6558,7 @@ int ObTransformUtils::convert_select_expr_to_column_expr(const common::ObIArray<
       ret = OB_ERR_UNEXPECTED;
       LOG_WARN("failed to find select expr inner stmt", K(ret));
     } else if (OB_ISNULL(col = outer_stmt.get_column_expr_by_id(table_id, column_id))) {
-      LOG_WARN("failed to get column expr by id", K(ret));
+      //do nothing
     } else if (OB_FAIL(column_exprs.push_back(col))) {
       LOG_WARN("failed to push back column expr", K(ret));
     }