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There’s a new release with a lot of goodies — speed, efficiency, user-friendliness, and new features. In particular some of Percona’s clients have sponsored features for things they need such as the ability to more frequently verify that slaves are in sync with their masters. If you need features, please ask Percona [...]

Scenario: Someone wants to know which of the over 50 MySQL users have certain privileges.

There are many ways to solve this problem. Some of these scenarios are tedious and repetitious, others take no time at all.

The issue, of course, lies in what the “certain” privileges are. If it is “who has the SUPER privilege?” then a simple

SELECT user,host FROM mysql.user WHERE Super_priv='Y';

is sufficient. If it is “who has write access to the foo database”, you might write:

SELECT user,host FROM db WHERE Db='foo' AND Select_priv='Y';

but that only shows who explicitly has read permissions on that database; it does not include those who have global read permissions. The full query would be:
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Slave delay can be a nightmare. I battle it every day and know plenty of people who curse the serialization problem of replication. For those who are not familiar with it, replication on MySQL slaves runs commands in series – one by one, while the master may run them in parallel. This fact usually causes bottlenecks. Consider these 2 examples:

• Between 1 and 100 UPDATE queries are constantly running on the master in parallel. If the slave IO is only fast enough to handle 50 of them without lagging, as soon as 51 start running, the slaves starts to lag.
• A more common problem is when one query takes an hour to run (let's say, it's an UPDATE with a big WHERE clause that doesn't use an index). In this case, the query runs on the master for an hour, which isn't a big problem because it doesn't block other queries. However, when the query moves over to the slaves, all of them start to lag because it plugs up the single …

Over in Maatkit-land, Daniel Nichter and I practice test-first programming, AKA test-driven development. That is, we write tests for each new feature or to catch regressions on each bug we fix. And — this is crucial — we write the tests before we write the code.* The tests should initially fail, which is a validation that the new code actually works and the tests actually verify this. If we don’t first write a failing testcase, then our code lacks a very important guarantee: “if you break this code, then the test case will tell you so.” (A test that doesn’t fail when the code fails isn’t worth writing.)

Most of the time when I do this, I write a test, it fails because I haven’t written any code yet, and I then go do some kind of …

The Maatkit toolkit is a real blessing for the MySQL DBA. And while its documentation is pretty good, in some cases it’s necessary to read carefully a second and third time to make sure you are not missing an important piece of information. In this article I will comment on mk-table-chksum and mk-table-sync. My comments are mostly aimed at those DBAs who are considering using these utilities with medium or larger-sized databases.

–replicate

This option allows you to store the checksum results on the master, in a table that will get replicated to the slaves. Although it might seem like overhead for a simple check, it really simplifies your life, especially when used in combination with …

Dear LazyWeb, I want to use my Ubuntu laptop (on amd64 BTW) to build an RPM of Maatkit that will work on all RPM-based distros. Is it possible? Or are there enough differences between the RPM-based distros that I can’t do it? Mind you, the finished RPM ought to just have some man pages and Perl scripts, so I don’t think it will be platform- or distro-specific. But I am just not an expert on it.

The second question is, what do I need to put into my Makefile to do this? My ‘make all’ currently builds a .zip, a .tar.gz, and a .deb package — what needs to change to make that include .rpm?

Someone who is willing to help create .spec files, etc, etc will be immediately given commit rights to Maatkit’s SVN repository!

Debian, packaging, …

Download Maatkit

Maatkit version 2152 is ready for download. This release is also known as the “is this project really alive?” release. We thought we should delay until MySQL released a new Community Server version. Just kidding — it has nothing to do with that.

This release is also very significant in that it’s the first one that has large code contributions by someone other than myself. As you may know, Percona (my employer) has hired the very talented Daniel Nichter, author of mysqlreport and other goodies, to help with Maatkit. So far it is a match made in heaven, and Daniel did …

Few days back, Baron re-introduced MySQL's command line pager command and described some cool tricks with maatkit's mk-visual-explain (one of my favorite tools). Soon after reading it, I wished if it was possible to describe regex based (on query) paging.

I have written a small hack, christened mysmartpager, that can actually do regex based paging for you.

The idea is simple, write a relay that will redirect the output based on to the desired pager. The problem was complex, there was no direct way of getting to know the original query. There are a couple of indirect ways of doing so, but of course with hurdles:

• Run mysql client with --xml option: This will print the output of each command in xml and the command itself is included in the xml. The downside was not many pagers (including …

Percona is looking to hire someone to develop Maatkit, among other things.

If I weren’t having so much fun being the consulting team lead, I’d be doing it myself. (In fact, I’m still hacking on it a lot. Got some pretty fun stuff done this weekend.) I don’t know what the rest of the world thinks, but I think Maatkit is a damn enjoyable project to work on. Hopefully someone else will have the same kind of mindset and want to get paid for it, unlike poor working-on-the-weekends me.

I’m not stepping away from the project. It’s just grown a lot, and there is room and money to grow it much more. This is actually the best compliment to the project: that it is worth hiring someone to keep improving it. Lots of people are using it, and there’s a lot …

Download Maatkit

Before I tell you what’s new, let me tell you how cool I think it would be if Maatkit were voted Sourceforge.net project of the year. Just something to think about :-) I suggest the “Best Tool or Utility for SysAdmins” category. You can actually click the Back button and nominate it for several categories. Not that anyone would do that, of course.

Also, if anyone wants to jump in and help out with bug fixes and new features, please, by all means. Maatkit is a true open-source project as well as being Free Software. If you can follow coding conventions and understand Perl, I’m a very benevolent dictator and would gladly grant commit rights. As it turns out, since I’ve joined Percona I’m interested in a whole different set of things, …