Not too long ago I attended a talk about a database called Datomic. My overall impressions of Datomic were pretty negative, but this blog post isn’t about that. This is about one of the things the speaker referenced a lot: immutability and its benefits. I hope to illustrate, if only sketchily, why a lot of sophisticated databases are actually leaps and bounds beyond the simplistic design of such immutable databases. This is in direct contradiction to what proponents of Datomic-like systems would have you believe; they’d tell you that their immutable database implementations are advanced. Reality is not so clear-cut.

Datomic and Immutability

The Datomic-in-a-nutshell is that it (apparently) uses an append-only B-tree to record data, and never updates any data after it’s written. I say “apparently” because the speaker didn’t know what an append-only B-tree was, but his detailed description matched AOBTs …

MySQL... We've blogged about MySQL before. Many times. We've shown bad ideas implemented in MySQL here: MySQL Bad Idea #384MySQL Bad Idea #573 But this beats everything. Check out this Stack Overflow question. It reads: "Why Oracle does not support 'group by 1,2,3'?". At first, I thought this user might have been confused because SQL … Continue reading MySQL Bad Idea #666 →

The MySQL Utilities Team is pleased to announce the latest GA release of MySQL Utilities. This release includes a number of improvements for usability, stability, and a few enhancements. We have also included a performance upgrade for exporting, importing, and copying databases.

Improvements
The following highlights a few of the more significant improvements.

* mysqldbexport, mysqldbimport, and mysqldbcopy have multiprocessing support that allows for much improved performance
* mysqlfrm can now generate a .frm file with storage engine substitution
* Mac OS X packages added!
* mysqlserverinfo now includes the log files (error, general, slow)
* mysqlprocgrep can now search and kill processes by id
* mysqlmetagrep can now search the body of routines with the new --body option
* all utilities report license type with --version and --help
* all utilities have the new …

I clicked around for a few moments but didn’t immediately see a license mentioned for the MariaDB knowledgebase. As far as I know, the MySQL documentation is not licensed in a way that would allow copying or derivative works, but at least some of the MariaDB Knowledge Base seems to be pretty similar to the corresponding MySQL documentation. See for example LOAD DATA LOCAL INFILE: MariaDB, MySQL.

Oracle’s MySQL documentation has a licensing notice that states:

You may create a printed copy of this documentation solely for your own personal use. Conversion to other formats is allowed as long as the actual content is not altered or edited in any way. You shall not publish or …

Enough negativity sometimes gets slung around that it’s easy to forget how much good is going on. I want to give a public thumbs-up to the great job the MySQL community team, especially Morgan Tocker, is doing. I don’t remember ever having so much good interaction with this team, not even in the “good old days”:

• Advance notice of things they’re thinking about doing (deprecating, changing, adding, etc)
• Heads-up via private emails about news and upcoming things of interest (new features, upcoming announcements that aren’t public yet, etc)
• Solicitation of opinion on proposals that are being floated internally (do you use this feature, would it hurt you if we removed this option, do you care about this legacy behavior we’re thinking about sanitizing)

I don’t know who or what has made this change happen, but it’s really welcome. I know Oracle is a giant company with all …

Here’s a trip down memory lane. I was just cleaning out some stuff and I found some notes I took from a hilarious MySQL seminar a few years back. I won’t say when or where, to protect the guilty.[1]

I found it so absurd that I had to write down what I was witnessing. Enough time has passed that we can probably all laugh about this now. Times and people have changed.

The seminar was a sales pitch in disguise, of course. The speakers were singing Powerpoint Karaoke to slides real tech people had written. Every now and then, when they advanced a slide, they must have had a panicked moment. “I don’t remember this slide at all!” they must have been thinking. So they’d mumble something really funny and trying-too-hard-to-be-casual about “oh, yeah, [insert topic here] but you all already know this, I won’t bore you with the details [advance slide hastily].” It’s strange how transparent that is to the audience.

…

I just tried out EXPLAIN UPDATE in MySQL 5.6 and found unexpected results. This query has no usable index:

EXPLAIN UPDATE ... WHERE col1 = 9 AND col2 = 'something'\G
*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: foo
         type: index
possible_keys: NULL
          key: PRIMARY
      key_len: 55
          ref: NULL
         rows: 51
        Extra: Using where

The EXPLAIN output makes it seem like a perfectly fine query, but it’s a full table scan. If I do the old trick of rewriting it to a SELECT I see that:

*************************** 1. row ***************************
           id: 1
  select_type: SIMPLE
        table: foo
         type: ALL
possible_keys: NULL
          key: NULL
      key_len: NULL
          ref: NULL
         rows: 51
        Extra: Using where

Should I file this as a bug? It seems like one to me.

Somebody asked how to create a SYNONYM in MySQL, which is interesting because MySQL doesn’t support synonyms. I thought the prior entry explained how to do it, but here’s a new post. However, you can create a view in one database that relies on a table in another database.

The following SQL statements create two databases and grant appropriate privileges to the student as the root superuser:

/* Create two databases. */
CREATE DATABASE seussdb;
CREATE DATABASE appdb;
 
/* Grant privileges to a student user. */
GRANT ALL ON seussdb.* TO student;
GRANT ALL ON appdb.* TO student;

Log out from the root superuser and reconnect as the student user. Then, the following code connects to the seuss …

There is a new release of the Connector/Arduino on Launchpad! See https://launchpad.net/mysql-arduino. The new version supports a number of refinements and a few new features. These include:

• Improved support for processing result sets
• Conditional compilation to omit result set handling features to save program space
• Support for the Arduino WiFi shield
• New version() method to check version of the connector
• Simplified download (no more patching SHA1!)

So What is It?
If you have never heard of Connector/Arduino, it is simply a library designed to allow the Arduino platform to connect to and issue queries to a MySQL Database server.

Simply add an Ethernet shield to your Arduino and use the library to connect your Arduino to a MySQL database server. Yes, no more web-based hand waving or third party systems! Cool.

New …

Due to the growing popularity of Connector/Arduino, the moderator of MySQL Forums has created a forum for us to meet up and discuss the connector. Yippie!

http://forums.mysql.com/list.php?175

While the forum has been started very recently, I expect it will grow quickly as people discover the connector for the first time and experienced users find new and interesting ways to use it. I hope to moderate the new forum periodically to answer questions and respond to posts. See you there!

Note: you need an account to write to the forum. Click on "register" in the upper right hand corner of the forum page to create an account if you do not already have one.