From 7ad278eefb6f462635d1f97b8a3bfb43e54457e4 Mon Sep 17 00:00:00 2001
From: "wangtao.2077" <wangtao.2077@bytedance.com>
Date: Tue, 26 Dec 2023 13:31:45 +0800
Subject: [PATCH] fix AddDefaultDatabaseVisitor bad performance

---
 src/Interpreters/AddDefaultDatabaseVisitor.h  |  7 ---
 .../02953_slow_create_view.reference          |  0
 .../0_stateless/02953_slow_create_view.sql    | 44 +++++++++++++++++++
 3 files changed, 44 insertions(+), 7 deletions(-)
 create mode 100644 tests/queries/0_stateless/02953_slow_create_view.reference
 create mode 100644 tests/queries/0_stateless/02953_slow_create_view.sql

diff --git a/src/Interpreters/AddDefaultDatabaseVisitor.h b/src/Interpreters/AddDefaultDatabaseVisitor.h
index 08d159b42ca..27639c4b813 100644
--- a/src/Interpreters/AddDefaultDatabaseVisitor.h
+++ b/src/Interpreters/AddDefaultDatabaseVisitor.h
@@ -148,8 +148,6 @@ private:
     {
         if (table_expression.database_and_table_name)
             tryVisit<ASTTableIdentifier>(table_expression.database_and_table_name);
-        else if (table_expression.subquery)
-            tryVisit<ASTSubquery>(table_expression.subquery);
     }
 
     void visit(const ASTTableIdentifier & identifier, ASTPtr & ast) const
@@ -167,11 +165,6 @@ private:
         ast = qualified_identifier;
     }
 
-    void visit(ASTSubquery & subquery, ASTPtr &) const
-    {
-        tryVisit<ASTSelectWithUnionQuery>(subquery.children[0]);
-    }
-
     void visit(ASTFunction & function, ASTPtr &) const
     {
         bool is_operator_in = functionIsInOrGlobalInOperator(function.name);
diff --git a/tests/queries/0_stateless/02953_slow_create_view.reference b/tests/queries/0_stateless/02953_slow_create_view.reference
new file mode 100644
index 00000000000..e69de29bb2d
diff --git a/tests/queries/0_stateless/02953_slow_create_view.sql b/tests/queries/0_stateless/02953_slow_create_view.sql
new file mode 100644
index 00000000000..7824bd97b92
--- /dev/null
+++ b/tests/queries/0_stateless/02953_slow_create_view.sql
@@ -0,0 +1,44 @@
+drop view if exists slow_view1;
+
+create view slow_view1 as
+with c1 as (select 1 as a),
+    c2 as (select a from c1),
+    c3 as (select a from c2),
+    c4 as (select a from c3),
+    c5 as (select a from c4),
+    c6 as (select a from c5),
+    c7 as (select a from c6),
+    c8 as (select a from c7),
+    c9 as (select a from c8),
+    c10 as (select a from c9),
+    c11 as (select a from c10),
+    c12 as (select a from c11),
+    c13 as (select a from c12),
+    c14 as (select a from c13),
+    c15 as (select a from c14),
+    c16 as (select a from c15),
+    c17 as (select a from c16),
+    c18 as (select a from c17),
+    c19 as (select a from c18),
+    c20 as (select a from c19),
+    c21 as (select a from c20),
+    c22 as (select a from c21),
+    c23 as (select a from c22),
+    c24 as (select a from c23),
+    c25 as (select a from c24),
+    c26 as (select a from c25),
+    c27 as (select a from c26),
+    c28 as (select a from c27),
+    c29 as (select a from c28),
+    c30 as (select a from c29),
+    c31 as (select a from c30),
+    c32 as (select a from c31),
+    c33 as (select a from c32),
+    c34 as (select a from c33),
+    c35 as (select a from c34),
+    c36 as (select a from c35),
+    c37 as (select a from c36),
+    c38 as (select a from c37),
+    c39 as (select a from c38),
+    c40 as (select a from c39)
+select a from c21;