The more I go through others SQL, there are some common mistakes that I see developers making over and over again, so I thought why not start a series of tips that can help developers optimize their queries and avoid common pitfalls. So this post is a part of that series of tips, and this is the first tip "Avoid using a wild card character at the start of a LIKE pattern".

Here's what's new for the trendy developer this week:

Java's future on Apple: Slightly less in doubt

Last week, it looked like Apple was all "You're not welcome here, Java." In the changeable world that is Jobsland, this week Apple was offering to marry the language, reiterating their support for Java in OS X, and indicating that they would be supplying code and resources to the OpenJDK project.

As I've noted before, this makes sense for Apple, because it gets them out of the JVM business, and makes Oracle the one-stop shopping solution for all your JDK and JRE needs. It also means that the Mac can be added as a regression-tested target for a new version of Java, hopefully avoiding the kind of Java versioning snafus that rendered IBM's SPSS (or is it PAWS this week?) statistics …

I’ve started an HTML manual for innotop, a “top” clone for MySQL. It includes screenshots. Right now I only have screenshots for the new U mode, which demonstrates how the User Statistics enhancements in Percona Server can show you which tables and indexes are most used.

No related posts.

This month’s Maatkit release, which just hit the download servers, contains a new feature for mk-query-digest: Apdex scores. The Apdex performance index is a sensible metric of how satisfactory the response time to a request is. Of all the scientific metrics I’ve seen, it’s the most practical; and of all the practical ones I’ve seen, it’s the most scientific.

To use this feature, you need to know what the Apdex threshold means, and you need to know how to configure this in mk-query-digest.

And then you can ask and answer practical questions such as “which classes of queries against this MySQL server are not satisfying users?” Or, because mk-query-digest supports the HTTP protocol, you can pose …

I’ve just uploaded the new release of innotop to Google Code. Short version of the changelog: works on MySQL 5.1 with the InnoDB plugin; more efficient; supports Percona/MariaDB USER_STATISTICS data; fixes a bunch of small annoying bugs.

Longer version:

2010-11-06: version 1.8.0

   Changes:
   * Don't re-fetch SHOW VARIABLES every iteration; it's too slow on many hosts.
   * Add a filter to remove EVENT threads in SHOW PROCESSLIST (issue 32).
   * Add a timestamp to output in -n mode, when -t is specified (issue 37).
   * Add a new U mode, for Percona/MariaDB USER_STATISTICS (issue 39).
   * Add support for millisecond query time in Percona Server (issue 39).
   * Display a summary of queries executed in Query List mode (issue 26).

   Bugs fixed:
   * Made config-file …

It’s been ages since we’ve had an update to innotop, or at least, it’s been a while since the changes were bundled up and released officially. Barring any bug reports against the trunk code, I’m about ready to release more than a year’s worth of improvements to it:

   Changes:
   * Don't re-fetch SHOW VARIABLES every iteration; it's too slow on many hosts.
   * Add a filter to remove EVENT threads in SHOW PROCESSLIST (issue 32).
   * Add a timestamp to output in -n mode, when -t is specified (issue 37).
   * Add a new U mode, for Percona/MariaDB USER_STATISTICS enhancements (issue 39).
   * Add support for millisecond query time in Percona Server (issue 39).
   * Display a summary of queries executed in Query List mode (issue 26).

   Bugs fixed:
   * Hostname parsing wasn't standards compliant (issue …

I see this all the time:

[product] scales linearly to hundreds of servers

I haven’t seen a benchmark yet that’s truly a straight line. I would like to see one.

Related posts:

1. How to scale writes with master-master replication in MySQL
2. Archive strategies for OLTP servers, Part 1
3. Archive strategies for OLTP servers, Part 3
4. Archive strategies for OLTP servers, Part 2
…

I don’t think this was widely publicized, but the Call for Proposals for the MySQL (and beyond) conference was extended a few days. It’ll be open through November 3rd.

Related posts:

1. O’Reilly MySQL Conference CfP ends today
2. Postgres folks, consider the 2011 MySQL conference
3. The MySQL Conference will be very good this year
4. How to use extended …

Josh Owens of Webpulp.tv just posted an interview with me. Lots of good questions about MySQL, performance optimization, and Percona’s version of the server. Thanks Josh!

Related posts:

1. You have the right to see code samples in an interview
2. Baron Schwartz on a podcast at MySQL Conference and Expo 2008
3. Grab your High Performance MySQL sample content
4. …

Pagination is used very frequently in many websites, be it search results or most popular posts they are seen everywhere. But the way how it is typically implemented is naive and prone to performance degradation. In this article I attempt on explaining the performance implications of poorly designed pagination implementation. I have also analyzed how Google, Yahoo and Facebook handle pagination implementation. Then finally i present my suggestion which will greatly improve the performance related to pagination.