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, 8 insertions, 12 deletions

diff --git a/sql/sql_help.cc b/sql/sql_help.cc
index 4ccaa6a055f..80ed12b5652 100644
--- a/sql/sql_help.cc
+++ b/sql/sql_help.cc
@@ -689,20 +689,16 @@ static bool mysqld_help_internal(THD *thd, const char *mask)
   uint mlen= strlen(mask);
   size_t i;
   MEM_ROOT *mem_root= thd->mem_root;
+  LEX_CSTRING MYSQL_HELP_TOPIC_NAME=    {STRING_WITH_LEN("help_topic") };
+  LEX_CSTRING MYSQL_HELP_CATEGORY_NAME= {STRING_WITH_LEN("help_category") };
+  LEX_CSTRING MYSQL_HELP_RELATION_NAME= {STRING_WITH_LEN("help_relation") };
+  LEX_CSTRING MYSQL_HELP_KEYWORD_NAME=  {STRING_WITH_LEN("help_keyword") };
   DBUG_ENTER("mysqld_help");
 
-  tables[0].init_one_table(C_STRING_WITH_LEN("mysql"),
-                           C_STRING_WITH_LEN("help_topic"),
-                           "help_topic", TL_READ);
-  tables[1].init_one_table(C_STRING_WITH_LEN("mysql"),
-                           C_STRING_WITH_LEN("help_category"),
-                           "help_category", TL_READ);
-  tables[2].init_one_table(C_STRING_WITH_LEN("mysql"),
-                           C_STRING_WITH_LEN("help_relation"),
-                           "help_relation", TL_READ);
-  tables[3].init_one_table(C_STRING_WITH_LEN("mysql"),
-                           C_STRING_WITH_LEN("help_keyword"),
-                           "help_keyword", TL_READ);
+  tables[0].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_TOPIC_NAME, 0, TL_READ);
+  tables[1].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_CATEGORY_NAME, 0, TL_READ);
+  tables[2].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_RELATION_NAME, 0, TL_READ);
+  tables[3].init_one_table(&MYSQL_SCHEMA_NAME, &MYSQL_HELP_KEYWORD_NAME, 0, TL_READ);
   tables[0].next_global= tables[0].next_local= 
     tables[0].next_name_resolution_table= &tables[1];
   tables[1].next_global= tables[1].next_local=