Changed database, tablename and alias to be LEX_CSTRING

This was done in, among other things:
- thd->db and thd->db_length
- TABLE_LIST tablename, db, alias and schema_name
- Audit plugin database name
- lex->db
- All db and table names in Alter_table_ctx
- st_select_lex db

Other things:
- Changed a lot of functions to take const LEX_CSTRING* as argument
  for db, table_name and alias. See init_one_table() as an example.
- Changed some function arguments from LEX_CSTRING to const LEX_CSTRING
- Changed some lists from LEX_STRING to LEX_CSTRING
- threads_mysql.result changed because process list_db wasn't always
  correctly updated
- New append_identifier() function that takes LEX_CSTRING* as arguments
- Added new element tmp_buff to Alter_table_ctx to separate temp name
  handling from temporary space
- Ensure we store the length after my_casedn_str() of table/db names
- Removed not used version of rename_table_in_stat_tables()
- Changed Natural_join_column::table_name and db_name() to never return
  NULL (used for print)
- thd->get_db() now returns db as a printable string (thd->db.str or "")

1 files changed, 2 insertions, 1 deletions

diff --git a/storage/oqgraph/ha_oqgraph.cc b/storage/oqgraph/ha_oqgraph.cc
index a4d1aa85948..be5ac309421 100644
--- a/storage/oqgraph/ha_oqgraph.cc
+++ b/storage/oqgraph/ha_oqgraph.cc
@@ -622,7 +622,8 @@ int ha_oqgraph::open(const char *name, int mode, uint test_if_locked)
     DBUG_RETURN(-1);
   }
 
-  if (enum open_frm_error err= open_table_from_share(thd, share, "",
+  if (enum open_frm_error err= open_table_from_share(thd, share,
+                                                     &empty_clex_str,
                             (uint) (HA_OPEN_KEYFILE | HA_TRY_READ_ONLY),
                             EXTRA_RECORD,
                             thd->open_options, edges, FALSE))