Table definition cache, part 2

The table opening process now works the following way:
- Create common TABLE_SHARE object
- Read the .frm file and unpack it into the TABLE_SHARE object
- Create a TABLE object based on the information in the TABLE_SHARE
  object and open a handler to the table object

Other noteworthy changes:
- In TABLE_SHARE the most common strings are now LEX_STRING's
- Better error message when table is not found
- Variable table_cache is now renamed 'table_open_cache'
- New variable 'table_definition_cache' that is the number of table defintions that will be cached
- strxnmov() calls are now fixed to avoid overflows
- strxnmov() will now always add one end \0 to result
- engine objects are now created with a TABLE_SHARE object instead of a TABLE object.
- After creating a field object one must call field->init(table) before using it

- For a busy system this change will give you:
 - Less memory usage for table object
 - Faster opening of tables (if it's has been in use or is in table definition cache)
 - Allow you to cache many table definitions objects
 - Faster drop of table

1 files changed, 4 insertions, 4 deletions

diff --git a/sql/parse_file.cc b/sql/parse_file.cc
index d3e5645bafc..4633261e4ed 100644
--- a/sql/parse_file.cc
+++ b/sql/parse_file.cc
@@ -355,11 +355,11 @@ my_bool rename_in_schema_file(const char *schema, const char *old_name,
 {
   char old_path[FN_REFLEN], new_path[FN_REFLEN], arc_path[FN_REFLEN];
 
-  strxnmov(old_path, FN_REFLEN, mysql_data_home, "/", schema, "/",
+  strxnmov(old_path, FN_REFLEN-1, mysql_data_home, "/", schema, "/",
            old_name, reg_ext, NullS);
   (void) unpack_filename(old_path, old_path);
 
-  strxnmov(new_path, FN_REFLEN, mysql_data_home, "/", schema, "/",
+  strxnmov(new_path, FN_REFLEN-1, mysql_data_home, "/", schema, "/",
            new_name, reg_ext, NullS);
   (void) unpack_filename(new_path, new_path);
 
@@ -367,7 +367,7 @@ my_bool rename_in_schema_file(const char *schema, const char *old_name,
     return 1;
 
   /* check if arc_dir exists */
-  strxnmov(arc_path, FN_REFLEN, mysql_data_home, "/", schema, "/arc", NullS);
+  strxnmov(arc_path, FN_REFLEN-1, mysql_data_home, "/", schema, "/arc", NullS);
   (void) unpack_filename(arc_path, arc_path);
   
   if (revision > 0 && !access(arc_path, F_OK))
@@ -414,7 +414,7 @@ sql_parse_prepare(const LEX_STRING *file_name, MEM_ROOT *mem_root,
   char *end, *sign;
   File_parser *parser;
   File file;
-  DBUG_ENTER("sql__parse_prepare");
+  DBUG_ENTER("sql_parse_prepare");
 
   if (!my_stat(file_name->str, &stat_info, MYF(MY_WME)))
   {