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, 3 insertions, 3 deletions

diff --git a/sql/ha_heap.h b/sql/ha_heap.h
index 9b93936b573..909b36f975b 100644
--- a/sql/ha_heap.h
+++ b/sql/ha_heap.h
@@ -31,7 +31,7 @@ class ha_heap: public handler
   uint    records_changed;
   bool    key_stats_ok;
 public:
-  ha_heap(TABLE *table);
+  ha_heap(TABLE_SHARE *table);
   ~ha_heap() {}
   const char *table_type() const
   {
@@ -40,7 +40,7 @@ public:
   }
   const char *index_type(uint inx)
   {
-    return ((table->key_info[inx].algorithm == HA_KEY_ALG_BTREE) ?
+    return ((table_share->key_info[inx].algorithm == HA_KEY_ALG_BTREE) ?
             "BTREE" : "HASH");
   }
   /* Rows also use a fixed-size format */
@@ -54,7 +54,7 @@ public:
   }
   ulong index_flags(uint inx, uint part, bool all_parts) const
   {
-    return ((table->key_info[inx].algorithm == HA_KEY_ALG_BTREE) ?
+    return ((table_share->key_info[inx].algorithm == HA_KEY_ALG_BTREE) ?
 	    HA_READ_NEXT | HA_READ_PREV | HA_READ_ORDER | HA_READ_RANGE :
 	    HA_ONLY_WHOLE_INDEX);
   }