From 4fb42a22e87392d032cd9c42039350204b5ed999 Mon Sep 17 00:00:00 2001
From: 2149 <260391947@qq.com>
Date: Thu, 17 Aug 2023 10:43:35 +0000
Subject: [PATCH] Fix subquery coalesce bug

---
 .../ob_transform_subquery_coalesce.cpp        | 53 ++++++++++++++++++-
 .../rewrite/ob_transform_subquery_coalesce.h  |  5 ++
 2 files changed, 57 insertions(+), 1 deletion(-)

diff --git a/src/sql/rewrite/ob_transform_subquery_coalesce.cpp b/src/sql/rewrite/ob_transform_subquery_coalesce.cpp
index cc751f7366..8e686363cc 100644
--- a/src/sql/rewrite/ob_transform_subquery_coalesce.cpp
+++ b/src/sql/rewrite/ob_transform_subquery_coalesce.cpp
@@ -91,7 +91,7 @@ int ObTransformSubqueryCoalesce::transform_one_stmt(common::ObIArray<ObParentDML
       } else if (OB_ISNULL(trans_stmt)) {
         // do nothing
       } else if (OB_FAIL(accept_transform(parent_stmts, stmt, trans_stmt, false, false, is_happened))) {
-        LOG_WARN("failed to accept transform", K(ret));
+        LOG_WARN("failed to accept transform", K(ret), KPC(trans_stmt));
       } else if (!is_happened) {
         // do nothing
       } else if (OB_FAIL(append(ctx_->equal_param_constraints_, cost_based_equal_infos))) {
@@ -401,6 +401,7 @@ int ObTransformSubqueryCoalesce::coalesce_same_any_all_exprs(ObDMLStmt *stmt,
   is_happened = false;
   bool force_trans = false;
   bool force_no_trans = false;
+  bool is_select_same = false;
   if (OB_ISNULL(stmt) || OB_ISNULL(ctx_)) {
     ret = OB_ERR_UNEXPECTED;
     LOG_WARN("params have null", K(ret), K(stmt), K(ctx_));
@@ -441,6 +442,13 @@ int ObTransformSubqueryCoalesce::coalesce_same_any_all_exprs(ObDMLStmt *stmt,
           LOG_WARN("failed to check stmt containment", K(ret));
         } else if (!map_info.is_select_item_equal_) {
           OPT_TRACE("stmts have different select items, can not coalesce");
+        } else if (OB_FAIL(check_select_items_same(first_query_ref->get_ref_stmt(),
+                                           second_query_ref->get_ref_stmt(),
+                                           map_info,
+                                           is_select_same))) {
+          LOG_WARN("check select items failed", K(ret));
+        } else if (!is_select_same) {
+          OPT_TRACE("The order of select items in two stmts is different, can not coalesce");
         } else if (relation == QUERY_LEFT_SUBSET || relation == QUERY_EQUAL) {
           remove_index = (type == T_ANY ? j : i);
           OPT_TRACE("right query contain left query, will coalesce suqbeury");
@@ -746,6 +754,7 @@ int ObTransformSubqueryCoalesce::compare_any_all_subqueries(ObDMLStmt *stmt,
   ObQueryRefRawExpr* first_query_ref = get_any_all_query_expr(param.any_expr_);
   ObRawExpr* second_left_expr = get_any_all_left_hand_expr(param.all_expr_);
   ObQueryRefRawExpr* second_query_ref = get_any_all_query_expr(param.all_expr_);
+  bool is_select_same = false;
   OPT_TRACE("try to coalesce any/all subquery:");
   OPT_TRACE("any expr:", param.any_expr_);
   OPT_TRACE("all expr:", param.all_expr_);
@@ -774,6 +783,15 @@ int ObTransformSubqueryCoalesce::compare_any_all_subqueries(ObDMLStmt *stmt,
                                                             param.map_info_,
                                                             relation))) {
     LOG_WARN("failed to check stmt containment", K(ret));
+  } else if (!param.map_info_.is_select_item_equal_) {
+    OPT_TRACE("stmts have different select items, can not coalesce");
+  } else if (OB_FAIL(check_select_items_same(first_query_ref->get_ref_stmt(),
+                                      second_query_ref->get_ref_stmt(),
+                                      param.map_info_,
+                                      is_select_same))) {
+    LOG_WARN("check select items failed", K(ret));
+  } else if (!is_select_same) {
+    OPT_TRACE("The order of select items in two stmts is different, can not coalesce");
   } else if (relation == QueryRelation::QUERY_RIGHT_SUBSET ||
              relation == QueryRelation::QUERY_EQUAL) {
     has_false_conds = true;
@@ -2635,3 +2653,36 @@ int ObTransformSubqueryCoalesce::sort_coalesce_stmts(Ob2DArray<CoalesceStmts *>
   }
   return ret;
 }
+
+int ObTransformSubqueryCoalesce::check_select_items_same(const ObDMLStmt *first,
+                                                         const ObDMLStmt *second,
+                                                         ObStmtMapInfo &map_info,
+                                                         bool &is_same)
+{
+  int ret = OB_SUCCESS;
+  is_same = true;
+  if (OB_ISNULL(first) || OB_ISNULL(second)) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("unexpected null", K(ret), KP(first), KP(second));
+  } else if (first->is_select_stmt() && second->is_select_stmt()) {
+    const ObSelectStmt *first_sel = static_cast<const ObSelectStmt *>(first);
+    const ObSelectStmt *second_sel = static_cast<const ObSelectStmt *>(second);
+    ObStmtCompareContext context(first, second, map_info, &first->get_query_ctx()->calculable_items_);
+    if (first_sel->get_select_item_size() != second_sel->get_select_item_size()) {
+      is_same = false;
+    }
+    for (int64_t i = 0; OB_SUCC(ret) && is_same && i < first_sel->get_select_item_size(); ++i) {
+      ObRawExpr *first_expr = first_sel->get_select_item(i).expr_;
+      ObRawExpr *second_expr = second_sel->get_select_item(i).expr_;
+      if (OB_ISNULL(first_expr) || OB_ISNULL(second_expr)) {
+        ret = OB_ERR_UNEXPECTED;
+        LOG_WARN("unexpected null", K(ret), KP(first_expr), KP(second_expr));
+      } else if (!first_expr->same_as(*second_expr, &context)) {
+        is_same = false;
+      }
+    }
+  } else {
+    //do nothing
+  }
+  return ret;
+}
diff --git a/src/sql/rewrite/ob_transform_subquery_coalesce.h b/src/sql/rewrite/ob_transform_subquery_coalesce.h
index ce9fd434eb..fab9573817 100644
--- a/src/sql/rewrite/ob_transform_subquery_coalesce.h
+++ b/src/sql/rewrite/ob_transform_subquery_coalesce.h
@@ -237,6 +237,11 @@ private:
 
   int sort_coalesce_stmts(Ob2DArray<CoalesceStmts *> &coalesce_stmts);
 
+  int check_select_items_same(const ObDMLStmt *first,
+                              const ObDMLStmt *second,
+                              ObStmtMapInfo &map_info,
+                              bool &is_same);
+
 private:
 
   ObQueryRefRawExpr * get_exists_query_expr(ObRawExpr *expr);