GitLab

The problem was an ab-use of last_rkey_length.
Formerly we saved the packed key length (of the search key)
in this element. But in certain cases it got replaced by 
the (packed) result key length.
Now we use a new element of MI_INFO to save the packed key 
length of the search key.


myisam/mi_dbug.c:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Fixed the recognition of NULL values in _mi_print_key().
myisam/mi_rkey.c:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Saved the packed key length in a new element of MI_INFO.
myisam/mi_search.c:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Added a comment and trace prints.
myisam/myisamdef.h:
  Bug#9112 - Merge table with composite index producing invalid results with some queries
  Added a new element to store the packed key length
  for...