Backport of revid:ingo.struewing@sun.com-20091223200354-r2uzbdkj2v6yv111

   Bug#47633 - assert in ha_myisammrg::info during OPTIMIZE
 
   The server crashed on an attempt to optimize a MERGE table with
   non-existent child table.
 
   mysql_admin_table() relied on the table to be successfully open
   if a table object had been allocated.
 
   Changed code to check return value of the open function before
   calling a handler:: function on it.

1 files changed, 15 insertions, 0 deletions

diff --git a/storage/myisam/mi_check.c b/storage/myisam/mi_check.c
index 0bcc022a0dc..25267bfb9ea 100644
--- a/storage/myisam/mi_check.c
+++ b/storage/myisam/mi_check.c
@@ -1736,6 +1736,21 @@ err:
     {
       mysql_file_close(new_file, MYF(0));
       info->dfile=new_file= -1;
+      /*
+        On Windows, the old data file cannot be deleted if it is either
+        open, or memory mapped. Closing the file won't remove the memory
+        map implicilty on Windows. We closed the data file, but we keep
+        the MyISAM table open. A memory map will be closed on the final
+        mi_close() only. So we need to unmap explicitly here. After
+        renaming the new file under the hook, we couldn't use the map of
+        the old file any more anyway.
+      */
+      if (info->s->file_map)
+      {
+        (void) my_munmap((char*) info->s->file_map,
+                         (size_t) info->s->mmaped_length);
+        info->s->file_map= NULL;
+      }
       if (change_to_newfile(share->data_file_name,MI_NAME_DEXT,
 			    DATA_TMP_EXT, share->base.raid_chunks,
 			    (param->testflag & T_BACKUP_DATA ?