Merge

innobase/include/srv0srv.h:
  Auto merged
innobase/srv/srv0srv.c:
  Auto merged
myisam/mi_create.c:
  Auto merged
myisam/mi_open.c:
  Auto merged
myisam/myisamdef.h:
  Auto merged
sql/ha_innodb.cc:
  Auto merged
mysql-test/r/myisam.result:
  SCCS merged
mysql-test/t/myisam.test:
  SCCS merged
sql/ha_innodb.h:
  SCCS merged

1 files changed, 15 insertions, 0 deletions

diff --git a/myisam/mi_create.c b/myisam/mi_create.c
index 1f6ed87182c..3e144cfcbfb 100644
--- a/myisam/mi_create.c
+++ b/myisam/mi_create.c
@@ -558,6 +558,21 @@ int mi_create(const char *name,uint keys,MI_KEYDEF *keydefs,
     create_flag=MY_DELETE_OLD;
   }
 
+  /*
+    If a MRG_MyISAM table is in use, the mapped MyISAM tables are open,
+    but no entry is made in the table cache for them.
+    A TRUNCATE command checks for the table in the cache only and could
+    be fooled to believe, the table is not open.
+    Pull the emergency brake in this situation. (Bug #8306)
+  */
+  if (test_if_reopen(filename))
+  {
+    my_printf_error(0, "MyISAM table '%s' is in use "
+                    "(most likely by a MERGE table). Try FLUSH TABLES.",
+                    MYF(0), name + dirname_length(name));
+    goto err;
+  }
+
   if ((file= my_create_with_symlink(linkname_ptr,
 				    filename,
 				    0, O_RDWR | O_TRUNC,