The latest from the MySQL community

Welcome readers to the seventy-sixth edition of Log Buffer, the weekly review of database blogs. As I mentioned in LB#75, this is Yule Log Buffer, a special edition for the busy holiday season. In lieu of a full edition, I’m throwing this one open to you, gentle readers, by asking for your [...]

PING mysqlnd.team (MySQL) - 56(84) bytes of data
64 bytes from mysqlnd.team - icmp_seq=1 ttl=3weeks time=1month

Yes, there are delays. But not for the reason that we are having any problems. We have been borrowed out to other teams recently. A short status report.

PONG from mysqlnd.team

Andrey could not resist and has continued researching on parallel and background query operation. Georg was not too happy about this. Not that Georg does not support the idea, no, but Andrey had some other urgent assignments. Well, Andrey sometimes works in sort of waves: do little for some time, hack like crazy on other days. Again, Miha Nedok from http://www.izklop.com/, our alpha-beta-everything-tester number one, has given Andrey’s code studies a test drive and he did not regret it. However, I haven’t tested anything myself. I cannot …

My first Podcast, yeah!

Early the a week I recorded a short introduction to CouchDB for PHP Abstract.

If you like to quote, or copy or anything (after all this is under a Creative Commons license), here’s the transcript:

CouchDB

CouchDB is a new database system that breaks with a lot of traditions. Prepare to be confused or even offended. While a lot is different from traditional data management systems, the core concepts should be familiar to you.

Try to forget, just for a moment, all you know about SQL, relations, replication and all simple and advanced techniques you use to solve your problems when it comes to data storage. Instead, remember the days when you were a beginning PHP developer (if you are a beginner, perfect). …

I have been talking about many theories in the past and in my last post, I decided to start doing something instead of just talking about it.
So here we go..

Adding a Business Rule

We need to start adding some logic-rules to the database. There are two ways you can do this:

1. To create a View with IFs and other functions - this will process the data every time to give you the results

2. To save the result of the logic to the database table using a trigger - this might save some of the repeating processes but will take up more space and might slow things down during new inserts.

Both of these, you can do in your application right now. You can make a complicated …

Just when I thought I?d be in for a quiet last day in the office before Christmas? IBM has announced that it is to acquire in-memory database specialist Solid Information Technology in a move that sees it competing directly up against the TimesTen functionality that Oracle acquired in June 2005.

The aqcuisition also has implications for MySQL given Solid’s development of the SolidDB for MySQL engine, an optional replacement for InnoDB (also of course acquired by Oracle).

While MySQL is in the firing line, it does not appear to be the intended …

MySQL CEO Marten Mickos has spoken before about how he is more interested in learning from the successes of Ikea, Ryanair and Virgin Mobile than he is the established proprietary software vendors. Even so, it was surprising to see that Red Hat has looked outside the software industry for its new president and CEO.

Jim Whitehurst was most recently chief operating officer at Delta, where he had responsibility for operations, sales …

The user has session data in memcached. It is set to expire after X period of time.

How do you update the database to know when the expiration happened?

Poll for the data.

When you create the session data add a "session_active" field to the account. If you create a session for the user set this to "on", otherwise default it to off.

Now insert the data into memcached and set an expire on it. Each time you fetch the data, touch it to last a bit longer.

How do you turn off the enum "session_active" in MySQL?

Write an Event in 5.1 and probe Memcached via UDF to find out if the data still exists. If it does not, update the field. Just select each row that showed an active session and check it.

I got asked this in IRC and had to think about the logic of this. I am not sure I would design a need into knowing if a session variable still existed or not, …

A

I'm a big fan of OpenID. However, pretty much all of my past uses of it have been experiments, demonstrations, or because I sought out OpenID enabled sites.

A couple of days ago, I finally used it "for real".

A client of MySQL's uses a system called projectpath.com. And when I first went to it, I saw that it is OpenID enabled!

It's kind of a pity that MySQL.com isn't an OpenID provider for it's staff, like Sun.com does, so that I could have used something like "http://openid.mysql.com/mark.atwood" for it. Instead I just used my personal OpenID of "http://mark.atwood.name/".

I’ve written before about how to figure out which connection is holding the InnoDB locks for which other connections are waiting. In other words, how to figure out who’s blocking you from getting work done when you get InnoDB lock timeouts or other InnoDB lock contention. The short and sweet: turn on the InnoDB lock monitor and use innotop to look at the locks held and waited-for. The InnoDB lock monitor has a few major disadvantages, though: