MySQL 5.5 milestone 2 released


MySQL has released its second milestone of the new series, inaugurated this year with MySQL 5.4.

The new installment, MySQL 5.5-m2, has several new features, of which the most notables ones are semi-synchronous replication, exception handling through in stored routines through SIGNAL and RESIGNAL, and partitioning enhancements.

A quick overview of partitioning and semi-synchronous replication is available in this blog. Hours after the release, Roland Bouman published a very charming example of how useful the new SIGNAL feature can be.

The new release, available in the usual MySQL download pages, comes with an enhanced user manual.

This release shows that MySQL is moving forward in the path of its new development cycle, leaving behind its previous inflexible model that was stalling innovation and contribution. With this agile cycle, mature features are added more dynamically, while the ones in need of more development are sent to the next milestone, without side effects.


You know, these MySQL releases have gotten really confusing. Just recently, there was a huge banner on to download 5.4 for "stability and performance", which turned out to be beta if you clicked on it, with 5.1 being the (recommended) GA release.

Now 5.4 and the giant banners have basically vanished from the site, replaced by some understated news of the 5.5 beta (calling it "m2" as if there was an "m1" there in the past). In the download section, 5.1 is still the recommended GA release.

Is MySQL going on permanent beta or something? Did 5.4 ever stabilize? All my weak search skills can find are the announcement of the new "drop unstable features from branches" development plans, and talking about Azalea.

Posted by sapphirecat on December 18, 2009 at 03:59 AM PST #

Version 5.1 is still the recommended GA release.
Version 5.4 has evolved into 5.5.
MySQL is not a permanent beta. This is the new release model.
Please read Kaj's blog, already mentioned in the text, for more information.

Posted by Giuseppe Maxia on December 19, 2009 at 05:05 AM PST #

Ditto for sapphirecat's comments. Where is the explanation of what happened to 5.4? I was under the impression that 5.4 would be first be released towards the end of 2009.

5.4 looked to be a nice interim release with primarily bug fixes and performance enhancements that could ship on-time.

Now it's "evolved" into 5.5, grown new features and will be released mid-2010?


Wonder now if I'll check back in mid-2010 and see a new "evolved" 5.6 scheduled for 2011? ugh.

Posted by WTFever on December 21, 2009 at 12:52 AM PST #

Giuseppe has given the short answer and I strongly suggest reading Kaj's blog.

Antony, it's called Milestone 2 because 5.4 was Milestone 1 on the way to the next GA.

Thanks for your comments about our communication - we can always improve it. But in trying to be open about our development process, you get to hear more than you probably want about what we're doing when plans change.

That all said, I suggest you and others are probably more interested in what's in Milestone 2. I'd encourage you to download it and try it.

Posted by Jeffrey Pugh on December 21, 2009 at 02:55 AM PST #

Post a Comment:
Comments are closed for this entry.