A.1.1: When did MySQL 5.1 become production-ready (GA)?
A.1.2: Can MySQL 5.1 do subqueries?
A.1.3: Can MySQL 5.1 peform multi-table inserts, updates, and deletes?
A.1.4: Does MySQL 5.1 have a Query Cache? Does it work on Server, Instance or Database?
A.1.5: Does MySQL 5.1 have Sequences?
Does MySQL 5.1 have a
function with fractions of seconds?
A.1.7: Does MySQL 5.1 work with multi-core processors?
A.1.8: Is there a hot backup tool for MyISAM like InnoDB Hot Backup?
A.1.9: Have there been there any improvements in error reporting when foreign keys fail? Does MySQL now report which column and reference failed?
A.1.10: Can MySQL 5.1 perform ACID transactions?
Questions and Answers
MySQL 5.0.15 was released for production use on 19 October 2005. We are now working on MySQL 5.1, which is currently in beta.
Yes. See 「サブクエリ構文」.
A multi-table insert can be accomplished using a trigger
FOR EACH ROW clause contains
INSERT statements within a
BEGIN ... END block. See
Yes. The Query Cache operates on the server level, caching complete result sets matched with the original query string. If an exactly identical query is made (which often happens, particularly in web applications), no parsing or execution is necessary; the result is sent directly from the cache. Various tuning options are available. See 「MySQL クエリ キャッシュ」.
No. However, MySQL has an
system, which in MySQL 5.1 can also handle
inserts in a multi-master replication setup. With the
--auto-increment-offset startup options,
you can set each server to generate auto-increment values
that don't conflict with other servers. The
--auto-increment-increment value should be
greater than the number of servers, and each server should
have a unique offset.
No. This is on the MySQL roadmap as a 「rolling feature」. This means that it is not a flagship feature, but will be implemented, development time permitting. Specific customer demand may change this scheduling.
However, MySQL does parse time strings with a fractional
component. See 「
Yes. MySQL is fully multi-threaded, and will make use of multiple CPUs, provided that the operating system supports them.
This is currently under development for a future MySQL release.
The foreign key support in
seen improvements in each major version of MySQL. Foreign
key support generic to all storage engines is scheduled for
MySQL 5.2; this should resolve any inadequacies in the
current storage engine specific implementation.
Yes. All current MySQL versions support transactions. The
InnoDB storage engine offers full ACID
transactions with row-level locking, multi-versioning,
non-locking repeatable reads, and all four SQL standard
NDB storage engine supports the
READ COMMITTED transaction isolation