MDEV-6193: Problems with multi-table updates that JOIN against read-only table

All underlying tables should share the same lock type.

mysql-test/r/multi_update.result

@@ -797,6 +797,8 @@ DROP TABLE t1,t2;
 #
 # MDEV-6139: UPDATE w/ join against MRG_MyISAM table with read-only
 # sub-table fails
+# MDEV-6193: Problems with multi-table updates that JOIN against
+# read-only table
 #
 CREATE TABLE t1 (
 id int(10) unsigned,
@@ -812,5 +814,13 @@ b int(11)
 ) ENGINE=MRG_MyISAM UNION=(t3);
 FLUSH TABLES;
 update t1 join t2 using (id) set t1.a=t2.b;
+create view v2 as select * from t2;
+update t1 join v2 using (id) set t1.a=0;
+create view v1 as select * from t3;
+update t1 join v1 using (id) set t1.a=0;
+update t1 join INFORMATION_SCHEMA.CHARACTER_SETS on (id=MAXLEN) set t1.a=0;
+create view v3 as select t2.id, t3.b from t2 join t3 using(id);
+update t1 join v3 using (id) set t1.a=0;
+drop view v1, v2, v3;
 drop table t2, t3, t1;
 end of 5.5 tests

mysql-test/t/multi_update.test

@@ -811,6 +811,8 @@ DROP TABLE t1,t2;
 --echo #
 --echo # MDEV-6139: UPDATE w/ join against MRG_MyISAM table with read-only
 --echo # sub-table fails
+--echo # MDEV-6193: Problems with multi-table updates that JOIN against
+--echo # read-only table
 --echo #
 
 CREATE TABLE t1 (
@@ -837,7 +839,14 @@ let $MYSQLD_DATADIR= `select @@datadir`;
 --enable_result_log
 
 update t1 join t2 using (id) set t1.a=t2.b;
-
+create view v2 as select * from t2;
+update t1 join v2 using (id) set t1.a=0;
+create view v1 as select * from t3;
+update t1 join v1 using (id) set t1.a=0;
+update t1 join INFORMATION_SCHEMA.CHARACTER_SETS on (id=MAXLEN) set t1.a=0;
+create view v3 as select t2.id, t3.b from t2 join t3 using(id);
+update t1 join v3 using (id) set t1.a=0;
+drop view v1, v2, v3;
 drop table t2, t3, t1;
 
 --echo end of 5.5 tests

sql/sql_update.cc

@@ -1300,11 +1300,11 @@ int mysql_multi_update_prepare(THD *thd)
         be write-locked (for example, trigger to be invoked might try
         to update this table).
       */
+      if (using_lock_tables)
         tl->lock_type= read_lock_type_for_table(thd, lex, tl);
+      else
+        tl->set_lock_type(thd, read_lock_type_for_table(thd, lex, tl));
       tl->updating= 0;
-      /* Update TABLE::lock_type accordingly. */
-      if (!tl->placeholder() && !using_lock_tables)
-        tl->table->file->set_lock_type(tl->lock_type);
     }
   }
   for (tl= table_list; tl; tl= tl->next_local)

sql/table.cc

@@ -6811,6 +6811,27 @@ bool TABLE_LIST::change_refs_to_fields()
 }
 
 
+void TABLE_LIST::set_lock_type(THD *thd, enum thr_lock_type lock)
+{
+  if (check_stack_overrun(thd, STACK_MIN_SIZE, (uchar *)&lock))
+    return;
+  /* we call it only when table is opened and it is "leaf" table*/
+  DBUG_ASSERT(table);
+  lock_type= lock;
+  /* table->file->get_table() can be 0 for derived tables */
+  if (table->file && table->file->get_table())
+    table->file->set_lock_type(lock);
+  if (is_merged_derived())
+  {
+    for (TABLE_LIST *table= get_single_select()->get_table_list();
+         table;
+         table= table->next_local)
+    {
+      table->set_lock_type(thd, lock);
+    }
+  }
+}
+
 uint TABLE_SHARE::actual_n_key_parts(THD *thd)
 {
   return use_ext_keys &&

sql/table.h

@@ -2151,6 +2151,7 @@ struct TABLE_LIST
     }
     return false;
   } 
+  void set_lock_type(THD* thd, enum thr_lock_type lock);
 
 private:
   bool prep_check_option(THD *thd, uint8 check_opt_type);