From 4f0873c04b6236039a7326c782b0a10f6dda7fd3 Mon Sep 17 00:00:00 2001
From: "gluh@mysql.com/mgluh.(none)" <>
Date: Fri, 22 Feb 2008 12:30:17 +0400
Subject: [PATCH] Bug#23588 SHOW COLUMNS on a temporary table causes locking
 issues skip lock_type update for temporary tables

---
 mysql-test/r/tablelock.result |  9 +++++++++
 mysql-test/t/tablelock.test   | 13 +++++++++++++
 sql/sql_base.cc               |  8 ++++++--
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/mysql-test/r/tablelock.result b/mysql-test/r/tablelock.result
index 2ffd8f928a9..6923ad40916 100644
--- a/mysql-test/r/tablelock.result
+++ b/mysql-test/r/tablelock.result
@@ -46,3 +46,12 @@ CREATE TABLE t2 (a int);
 lock tables t1 write,t1 as b write, t2 write, t2 as c read;
 drop table t2,t1;
 unlock tables;
+create temporary table t1(f1 int);
+lock tables t1 write;
+insert into t1 values (1);
+show columns from t1;
+Field	Type	Null	Key	Default	Extra
+f1	int(11)	YES		NULL	
+insert into t1 values(2);
+drop table t1;
+unlock tables;
diff --git a/mysql-test/t/tablelock.test b/mysql-test/t/tablelock.test
index 95533903b45..5ac93f09ac1 100644
--- a/mysql-test/t/tablelock.test
+++ b/mysql-test/t/tablelock.test
@@ -49,3 +49,16 @@ drop table t2,t1;
 unlock tables;
 
 # End of 4.1 tests
+
+#
+# Bug#23588 SHOW COLUMNS on a temporary table causes locking issues
+#
+create temporary table t1(f1 int);
+lock tables t1 write;
+insert into t1 values (1);
+show columns from t1;
+insert into t1 values(2);
+drop table t1;
+unlock tables;
+
+# End of 5.0 tests
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 8190b3eeacd..c9f20b3d71b 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -2852,8 +2852,12 @@ int open_tables(THD *thd, TABLE_LIST **start, uint *counter, uint flags)
     }
 
     if (tables->lock_type != TL_UNLOCK && ! thd->locked_tables)
-      tables->table->reginfo.lock_type= tables->lock_type == TL_WRITE_DEFAULT ?
-        thd->update_lock_default : tables->lock_type;
+    {
+      if (tables->lock_type == TL_WRITE_DEFAULT)
+        tables->table->reginfo.lock_type= thd->update_lock_default;
+      else if (tables->table->s->tmp_table == NO_TMP_TABLE)
+        tables->table->reginfo.lock_type= tables->lock_type;
+    }
     tables->table->grant= tables->grant;
 
 process_view_routines: