MySQL 5.0.1 Alpha 发布

王朝mysql·作者佚名  2006-01-09
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昨天,MySQL 5.0.1 Alpha 发布,包含很多新特性,详情请看 Changelog 。

下载:http://dev.mysql.com/downloads/mysql/5.0.1-snapshot.html

News from the ChangeLog:

Functionality added or changed:

* Added support of read only and updateable VIEWs based on single

table or other updateable VIEWs.

* Implemented a new ``greedy search'' optimizer that can

significantly reduce the time spent on optimizing the query in

some many-table joins. (You are affected if not only some

particular SELECT is slow, but even using EXPLAIN for it takes a

noticeable amount of time.) Two new system variables,

optimizer_search_depth and optimizer_prune_level, can be used to

fine-tune optimizer behavior.

* Warning: Incompatible change! C API change: mysql_shutdown() now

requires a second argument. This is a source-level incompatibility

that affects how you compile client programs; it does not affect

the ability of compiled clients to communicate with older servers.

See section "mysql_shutdown()" in the manual.

* A stored procedure is no longer "global" - i.e. it now belongs to a

specific database:

* When a database is dropped, all routines belonging to that

database are also dropped.

* Procedure names may be qualified, e.g. `db.p()'

* When executed from another database an implicit "use db" is

in effect.

* Explicit "use db" is no longer allowed in a stored procedure.

* Fixed SHOW TABLES output field name and values according to

standard. Field name changed from Type to table_type, values are

BASE TABLE, VIEW and ERROR. (Bug #4603)

* Added sql_updatable_view_key system variable.

* Added --replicate-same-server-id server option.

* Added Last_query_cost status variable that reports optimizer cost

for last compiled query.

* Added option --to-last-log to mysqlbinlog, for use in conjunction

with --read-from-remote-server.

* Added --innodb-safe-binlog server option, which adds consistency

guarantees between the content of InnoDB tables and the binary

log. See section "The Binary Log" in the manual.

* OPTIMIZE TABLE for InnoDB tables is now mapped to ALTER TABLE

instead of ANALYZE TABLE.

* sync_frm is now a settable global variable (not only a startup

option).

* For replication of MEMORY (HEAP) tables: Made the master

automatically write a DELETE FROM statement to its binary log when

a MEMORY table is opened for the first time since master's

startup. This is for the case where the slave has replicated a

non-empty MEMORY table, then the master is shut down and

restarted: the table is now empty on master; the DELETE FROM

empties it on slave too. Note that even with this fix, between the

master's restart and the first use of the table on master, the

slave still has out-of-date data in the table. But if you use the

--init-file option to populate the MEMORY table on the master at

startup, it ensures that the failing time interval is zero. (Bug

#2477)

* When a session having open temporary tables terminates, the

statement automatically written to the binary log is now DROP

TEMPORARY TABLE IF EXISTS instead of DROP TEMPORARY TABLE, for

more robustness.

* The MySQL server now returns an error if SET SQL_LOG_BIN is issued

by a user without the SUPER privilege (in previous versions it

just silently ignored the statement in this case).

* Changed that when the MySQL server has binary logging disabled

(that is, no log-bin option was used) then no transaction binlog

cache is allocated for connections (this should save

binlog_cache_size bytes of memory (32 kilobytes by default) for

every connection).

* Added the sync_binlog=N global variable and startup option, which

makes the MySQL server synchronize its binary log to disk

(fdatasync()) after every Nth write to the binary log.

* Changed the slave SQL thread to print less useless error messages

(no more message duplication; no more message when an error is

skipped (because of slave-skip-errors).

* DROP DATABASE IF EXISTS, DROP TABLE IF EXISTS, single-table DELETE

and single-table UPDATE are now written to the binary log even if

they changed nothing on the master (for example, even if the

DELETE matched no row). The old behavior sometimes caused bad

surprises in replication setups.

* Replication and mysqlbinlog now have better support for the case

that the session character set and collation variables are changed

within a given session. See section "Replication Features and Known

Problems" in the manual.

 
 
 
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