From 73b58ac4873eb98057cc1f57b8e6fde53aa9b29d Mon Sep 17 00:00:00 2001
From: Dmitry Shulga <dmitry.shulga@mariadb.com>
Date: Thu, 1 Aug 2024 13:07:12 +0700
Subject: [PATCH] MDEV-34649: Memory leaks on running DELETE statement in PS
 mode with positional parameters

Re-design of a way for handling the DELETE statement introduced by
the task MDEV-28883, added regression caused by missing reset of
the data member current_select->first_cond_optimization on handling
the DELETE statement that results in a memory leaks on second execution
of the same DELETE statement in PS mode.

To fix memory leaks, added set of the data member
  current_select->first_cond_optimization
to the value false on finishing execution of DELETE statement.
---
 mysql-test/main/ps_mem_leaks.result | 14 ++++++++++++++
 mysql-test/main/ps_mem_leaks.test   | 18 ++++++++++++++++++
 sql/sql_delete.cc                   |  1 +
 3 files changed, 33 insertions(+)

diff --git a/mysql-test/main/ps_mem_leaks.result b/mysql-test/main/ps_mem_leaks.result
index ebbccb71c6b..b915329ff18 100644
--- a/mysql-test/main/ps_mem_leaks.result
+++ b/mysql-test/main/ps_mem_leaks.result
@@ -148,3 +148,17 @@ CALL p1(2);
 DROP TABLE t1;
 DROP PROCEDURE p1;
 # End of 10.11 tests
+#
+# MDEV-34649: Memory leaks on running DELETE statement in PS mode with positional parameters
+#
+CREATE TABLE t1 (a INT, b VARCHAR(30)) CHARSET=utf8mb4;
+INSERT INTO t1 VALUES (1, 'one'), (0, NULL), (3, 'three'), (4, 'four');
+PREPARE stmt FROM 'DELETE FROM t1 WHERE b=?' ;
+SET @arg00=NULL;
+EXECUTE stmt USING @arg00;
+SET @arg00='one';
+EXECUTE stmt USING @arg00;
+# Clean up
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1;
+# End of 11.1
diff --git a/mysql-test/main/ps_mem_leaks.test b/mysql-test/main/ps_mem_leaks.test
index 75381e13116..e824200d0fb 100644
--- a/mysql-test/main/ps_mem_leaks.test
+++ b/mysql-test/main/ps_mem_leaks.test
@@ -167,3 +167,21 @@ DROP TABLE t1;
 DROP PROCEDURE p1;
 
 --echo # End of 10.11 tests
+
+--echo #
+--echo # MDEV-34649: Memory leaks on running DELETE statement in PS mode with positional parameters
+--echo #
+CREATE TABLE t1 (a INT, b VARCHAR(30)) CHARSET=utf8mb4;
+INSERT INTO t1 VALUES (1, 'one'), (0, NULL), (3, 'three'), (4, 'four');
+PREPARE stmt FROM 'DELETE FROM t1 WHERE b=?' ;
+SET @arg00=NULL;
+EXECUTE stmt USING @arg00;
+SET @arg00='one';
+# Without the patch, attempt to run the same prepared statement the second time
+# would result in memory leaks
+EXECUTE stmt USING @arg00;
+--echo # Clean up
+DEALLOCATE PREPARE stmt;
+DROP TABLE t1;
+
+--echo # End of 11.1
diff --git a/sql/sql_delete.cc b/sql/sql_delete.cc
index b7b3b79bbb6..b1fc89b2a28 100644
--- a/sql/sql_delete.cc
+++ b/sql/sql_delete.cc
@@ -912,6 +912,7 @@ cleanup:
   {
     thd->lex->current_select->save_leaf_tables(thd);
     thd->lex->current_select->leaf_tables_saved= true;
+    thd->lex->current_select->first_cond_optimization= false;
   }
 
   delete deltempfile;