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Table definition cache, part 2

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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
This commit is contained in:
monty@mysql.com
2005-11-23 22:45:02 +02:00
parent b167a6679b
commit e42c980967
100 changed files with 3655 additions and 2121 deletions
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10
mysql-test/r/variables.result
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@@ -376,7 +376,7 @@ set sql_quote_show_create=1;
set sql_safe_updates=1;
set sql_select_limit=1;
set sql_warnings=1;
set global table_cache=100;
set global table_open_cache=100;
set storage_engine=myisam;
set global thread_cache_size=100;
set timestamp=1, timestamp=default;
@@ -508,11 +508,11 @@ SET GLOBAL MYISAM_DATA_POINTER_SIZE= 7;
SHOW VARIABLES LIKE 'MYISAM_DATA_POINTER_SIZE';
Variable_name Value
myisam_data_pointer_size 7
SET GLOBAL table_cache=-1;
SHOW VARIABLES LIKE 'table_cache';
SET GLOBAL table_open_cache=-1;
SHOW VARIABLES LIKE 'table_open_cache';
Variable_name Value
table_cache 1
SET GLOBAL table_cache=DEFAULT;
table_open_cache 1
SET GLOBAL table_open_cache=DEFAULT;
set character_set_results=NULL;
select ifnull(@@character_set_results,"really null");
ifnull(@@character_set_results,"really null")