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, 5 insertions, 5 deletions

diff --git a/sql/events.cc b/sql/events.cc
index 3ad546217a7..2fbb16861f6 100644
--- a/sql/events.cc
+++ b/sql/events.cc
@@ -826,12 +826,12 @@ Events::fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */)
   */
   if (thd->lex->sql_command == SQLCOM_SHOW_EVENTS)
   {
-    DBUG_ASSERT(thd->lex->select_lex.db);
-    if (!is_infoschema_db(thd->lex->select_lex.db) && // There is no events in I_S
-        check_access(thd, EVENT_ACL, thd->lex->select_lex.db,
+    DBUG_ASSERT(thd->lex->select_lex.db.str);
+    if (!is_infoschema_db(&thd->lex->select_lex.db) && // There is no events in I_S
+        check_access(thd, EVENT_ACL, thd->lex->select_lex.db.str,
                      NULL, NULL, 0, 0))
       DBUG_RETURN(1);
-    db= normalize_db_name(thd->lex->select_lex.db, db_tmp, sizeof(db_tmp));
+    db= normalize_db_name(thd->lex->select_lex.db.str, db_tmp, sizeof(db_tmp));
   }
   ret= db_repository->fill_schema_events(thd, tables, db);
 
@@ -1252,7 +1252,7 @@ int wsrep_create_event_query(THD *thd, uchar** buf, size_t* buf_len)
   if (create_query_string(thd, &log_query))
   {
     WSREP_WARN("events create string failed: schema: %s, query: %s",
-               (thd->db ? thd->db : "(null)"), thd->query());
+               thd->get_db(), thd->query());
     return 1;
   }
   return wsrep_to_buf_helper(thd, log_query.ptr(), log_query.length(), buf, buf_len);