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| Тема |
 MySQL 4.0 released - Alpha |
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| Автор |
salle (Един такъв) |
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| Публикувано | 16.10.01 11:38 |
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Upgrading From Version 3.23 to Version 4.0
You can use your old data files without any modification with Version 4.0. If you want to move your data from a MySQL 4.0 server to an older server, you have to use mysqldump.
Old clients should work with a Version 4.0 server without any problems.
The following lists tell what you have to watch out for when upgrading to version 4.0;
* `safe_mysqld' is renamed to `mysqld_safe'.
* The old C API functions mysql_drop_db, mysql_create_db and mysql_connect are not supported anymore, unless one compiles MySQL with USE_OLD_FUNCTIONS. Instead of doing this, one should change the client to use the new 4.0 API.
* In the MYSQL_FIELD structure, length and max_length has changed from unsigned int to unsigned long. This should not cause any other problems than some warnings if you use these to printf() type function.
* You should use TRUNCATE TABLE when you want to delete all rows from a table and you don't care of how many rows where deleted. (Because TRUNCATE TABLE is faster than DELETE FROM table_name).
* You will get an error if you have an active LOCK TABLES or transaction when trying to execute TRUNCATE TABLE or DROP DATABASE.
* You should use integers to store values in BIGINT columns (instead of using strings as you did in MySQL 3.23). Using strings will still work, but using integers is more efficient.
* Format of SHOW OPEN TABLE has changed.
* Multithreaded clients should use mysql_thread_init() and mysql_thread_end(). See section 8.4.8 How to Make a Threaded Client.
Changes in release 4.0.0
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* Added documentation for `libmysqld', the embedded MySQL server
library. Also added example programs (a `mysql' client and
`mysqltest' test program) which use `libmysqld'.
* Removed all Gemini hooks from MySQL.
* Removed `my_thread_init()' and `my_thread_end()' from mysql_com.h,
and added `mysql_thread_init()' and `mysql_thread_end()' to
mysql.h.
* Secure connections (with SSL).
* Unsigned `BIGINT' constants now work. `MIN()' and `MAX()' now
handles signed and unsigned `BIGINT' numbers correctly.
* New character set `latin_de' which provides correct German sorting.
* `TRUNCATE TABLE' and `DELETE FROM table_name' are now separate
functions. One bonus is that `DELETE FROM table_name' now returns
the number of deleted rows.
* `DROP DATABASE' now executes a `DROP TABLE' on all tables in the
database, which fixes a problem with InnoDB tables.
* Added support for `UNION'.
* A new `HANDLER' interface to `MyISAM' tables.
* Added support for `INSERT' on `MERGE' tables. Patch from Benjamin
Pflugmann.
* Changed `WEEK(#,0)' to match the calender in the USA.
* `COUNT(DISTINCT)' is about 30% faster.
* Speed up all internal list handling.
* Speed up `IS NULL()' and some other internal primitives.
* Creating full text indexes are now much faster.
* Tree-like cache to speed up bulk inserts and
`myisam_bulk_insert_tree_size' variable.
* Searching on packed (`CHAR'/`VARCHAR') keys are now much faster.
* Optimized queries of type: `SELECT DISTINCT * from table_name
ORDER by key_part1 LIMIT #'
* `SHOW CREATE TABLE' now shows all table attributes.
* `ORDER BY ... DESC' can now use keys.
* `LOAD DATA FROM MASTER' "auto-magically" sets up a slave.
* Renamed `safe_mysqld' to `mysqld_safe'.
* Added support for symbolic links to `MyISAM' tables. Symlink
handling is now enabled by default for Windows.
* `LOAD DATA FROM MASTER' "auto-magically" sets up a slave.
* Added `SQL_CALC_FOUND_ROWS' and `FOUND_ROWS()'. This makes it
possible to know how many rows a query would have returned without
a `LIMIT' clause.
* Changed output format of `SHOW OPEN TABLES'.
* Allow `SELECT expression LIMIT ...'.
* Added `IDENTITY' as a synonym for `AUTO_INCREMENT' (like Sybase).
* Added `ORDER BY' syntax to `UPDATE' and `DELETE'.
* `SHOW INDEXES' is now a synonym for `SHOW INDEX'.
* Added `ALTER TABLE table_name DISABLE KEYS' and `ALTER TABLE
table_name ENABLE KEYS' commands.
* Allow one to use `IN' instead of `FROM' in `SHOW' commands.
* Allow ANSI SQL syntax `X'hexadecimal-number''
* Cleaned up global lock handling for `FLUSH TABLES WITH READ LOCK'
* Fixed problem with `DATETIME = constant' in `WHERE' optimization.
* Added options `--master-data' and `--no-autocommit' to `mysqldump'
(Thanks to Brian Aker for this).
* Added script `mysql_explain_log.sh' to distribution. (Thanks to
mobile.de).
Linux is like a wigwam - No Windows, No Gates, Apache inside
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