From e1876e7f78f6011a5759e4a2a549c057f21efcc9 Mon Sep 17 00:00:00 2001
From: Dmitry Shulga <dmitry.shulga@mariadb.com>
Date: Wed, 27 Mar 2024 20:44:05 +0700
Subject: [PATCH] MDEV-33768: Memory leak found in the test main.constraints
 run with --ps-protocol against a server built with the option
 -DWITH_PROTECT_STATEMENT_MEMROOT

The discovered memory leak was introduced by the commit
  762bf7a03b6214f091a66ca8683df341112d7d4a
    (MDEV-22602 Disable UPDATE CASCADE for SQL constraints)

The reason why a memory leaked on running the test main.constraints
is that a statement arena was used for allocation a memory
for storing a constraint name. A constraint name is an entity having
temporary nature by its design so runtime arena should be used for its
allocation.
---
 mysql-test/main/constraints.result | 13 +++++++++++++
 mysql-test/main/constraints.test   | 15 +++++++++++++++
 sql/sql_table.cc                   |  3 ++-
 3 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/mysql-test/main/constraints.result b/mysql-test/main/constraints.result
index 105ea7cf1f4..77a25f5ad46 100644
--- a/mysql-test/main/constraints.result
+++ b/mysql-test/main/constraints.result
@@ -235,3 +235,16 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1 COLLATE=latin1_swedish_ci
 drop procedure sp;
 drop table t1;
+#
+# MDEV-33768: Memory leak found in the test main.constraints run with --ps-protocol against a server built with the option -DWITH_PROTECT_STATEMENT_MEMROOT
+# This test case was added by reviewer's request.
+#
+PREPARE stmt FROM 'CREATE TABLE t1 (a INT)';
+EXECUTE stmt;
+DROP TABLE t1;
+EXECUTE stmt;
+EXECUTE stmt;
+ERROR 42S01: Table 't1' already exists
+# Clean up
+DROP TABLE t1;
+DEALLOCATE PREPARE stmt;
diff --git a/mysql-test/main/constraints.test b/mysql-test/main/constraints.test
index 5c673f9be81..83f3394d6f6 100644
--- a/mysql-test/main/constraints.test
+++ b/mysql-test/main/constraints.test
@@ -189,3 +189,18 @@ call sp;
 show create table t1;
 drop procedure sp;
 drop table t1;
+
+--echo #
+--echo # MDEV-33768: Memory leak found in the test main.constraints run with --ps-protocol against a server built with the option -DWITH_PROTECT_STATEMENT_MEMROOT
+--echo # This test case was added by reviewer's request.
+--echo #
+PREPARE stmt FROM 'CREATE TABLE t1 (a INT)';
+EXECUTE stmt;
+DROP TABLE t1;
+EXECUTE stmt;
+--error ER_TABLE_EXISTS_ERROR
+EXECUTE stmt;
+
+--echo # Clean up
+DROP TABLE t1;
+DEALLOCATE PREPARE stmt;
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 839438dfc30..dc1a7060643 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -5861,7 +5861,8 @@ static bool make_unique_constraint_name(THD *thd, LEX_CSTRING *name,
     if (!check)                                 // Found unique name
     {
       name->length= (size_t) (real_end - buff);
-      name->str= strmake_root(thd->stmt_arena->mem_root, buff, name->length);
+      name->str= thd->strmake(buff, name->length);
+
       return (name->str == NULL);
     }
   }