Sometimes I have seen and heard about that a data node gets stuck in start phase 101.

Unfortunately it is difficult to reproduce this (found no way yet), so no bug fix is in the pipe yet.

What happens is that in sp 101, the starting data node (actually a block called SUMA) should reconnect to the mysql server and take over the event handling (sending events to the mysql server), but it never gets the reconnect to the mysql server(s). A better explanation is here :)

If you see your data node stuck here then try the following:
1) Restart the mysql servers (one by one), the data node should now start
or
2) Restart the mysql servers and restart the data node.

Only do 2) if 1) does not work.

And if you know how to reproduce - …

TOTD #97 showed how to install GlassFish Tools Bundle for Eclipse 1.1. Basically there are two options - either install Eclipse 3.4.2 with WTP and pre-bundled/configured with GlassFish v2/v3, MySQL JDBC driver and other features. Or if you are using Eclipse 3.5, then you can install the plug-in separately and get most of the functionality.

TOTD #98 showed how to create a simple Metro/JAX-WS compliant Web service using that bundle and deploy on GlassFish.

This Tip Of The …

You don't know anything about databases and want to get rid of this social stigma? But you don't want to read a 500 pages book about theoretical aspects of relational database management system written by an aged computer science professor who thinks "real life" must be the name of a theater next to the campus?

In this case, this book is just what the nurse ordered: The Manga Guide to Databases.

The story starts like this:

Princess Ruruna and Cain have a problem: Their fruit-selling is a tangle of conflicting and duplicated data, and sorting the melons from the apples and strawberries is causing real difficulties. But what can they do?

Yes, of course they start setting up a database.

This book is fun, but it's also serious: lots of examples and exercises, and an appendix of frequently used SQL statements gives the tools you need to create …

As all you Mac users (and probably many non-Macies) know Apple released Snow Leopard (Mac OS X 10.6) recently, even though this release was announced for September previously. Since a large part of the MySQL Workbench user base works on OS X it was clear that many of you will test Workbench on the new OS. However, so far we haven’t had the opportunity to do the same (too busy fixing bugs on released OSes) and hence we did not know about incompatibility problems there.

In the meantime several users did tests and reported us a crash on startup of the application, which means you cannot use MySQL Workbench on Snow Leopard for the time being. We are currently preparing build, test and developer machines with it and will hand out a fixed WB release as soon as possible. So, please stay patient. It’s only a matter of days.

TOTD #97 showed how to install GlassFish Tools Bundle for Eclipse 1.1. Basically there are two options - either install Eclipse 3.4.2 with WTP and pre-bundled/configured with GlassFish v2/v3, MySQL JDBC driver and other features. Or if you are using Eclipse 3.5, then you can install the plug-in separately and get most of the functionality.

TOTD #98 showed how to create a simple Metro/JAX-WS compliant Web service using that bundle and deploy on GlassFish.

This Tip Of The …

TOTD #97 showed how to install GlassFish Tools Bundle for Eclipse 1.1. Basically there are two options - either install Eclipse 3.4.2 with WTP and pre-bundled/configured with GlassFish v2/v3, MySQL JDBC driver and other features. Or if you are using Eclipse 3.5, then you can install the plug-in separately and get most of the functionality.

TOTD #98 showed how to create a simple Metro/JAX-WS compliant Web service using that bundle and deploy on GlassFish.

This Tip Of The …

You don't know anything about databases and want to get rid of this social stigma? But you don't want to read a 500 pages book about theoretical aspects of relational database management system written by an aged computer science professor who thinks "real life" must be the name of a theater next to the campus?

In this case, this book is just what the nurse ordered: The Manga Guide to Databases.

The story starts like this:

Princess Ruruna and Cain have a problem: Their fruit-selling is a tangle of conflicting and duplicated data, and sorting the melons from the apples and strawberries is causing real difficulties. But what can they do?

Yes, of course they start setting up a database.

This book is fun, but it's also serious: lots of examples and exercises, and an appendix of frequently used SQL statements gives the tools you need to create …

You don't know anything about databases and want to get rid of this social stigma? But you don't want to read a 500 pages book about theoretical aspects of relational database management system written by an aged computer science professor who thinks "real life" must be the name of a theater next to the campus?

In this case, this book is just what the nurse ordered: The Manga Guide to Databases.

The story starts like this:

Princess Ruruna and Cain have a problem: Their fruit-selling is a tangle of conflicting and duplicated data, and sorting the melons from the apples and strawberries is causing real difficulties. But what can they do?

Yes, of course they start setting up a database.

This book is fun, but it's also serious: lots of examples and exercises, and an appendix of frequently used SQL statements gives the tools you need to create …

I’ve been thinking recently about the failure scenarios of MySQL replication clusters, such as master-master pairs or master-master-with-slaves. There are a few tools that are designed to help manage failover and load balancing in such clusters, by moving virtual IP addresses around. The ones I’m familiar with don’t always do the right thing when an irregularity is detected. I’ve been debating what the best way to do replication clustering with automatic failover really is.

I’d like to hear your thoughts on the following question: what types of scenarios require what kind of response from such a tool?

I can think of a number of failures. Let me give just a few simple examples in a master-master pair:

Problem: Query overload on the writable master makes mysqld unresponsive

Do nothing. Moving the queries to another server will cause cascading failures.

Problem: The …

A short time ago in a galaxy nearby, Domas Mituzas wrote about contention profiling with GDB stack traces. Mark Callaghan found the technique useful, and contributed an awk script (in the comments) to aggregate stack traces and identify which things are blocking most threads. I’ve used it myself a time or five. But I’ve found myself wanting it to be fancier, for various reasons. So I wrote a little utility that can aggregate and pretty-print backtraces. It can handle unresolved symbols, and aggregate by only the first N lines of the stack trace. Here’s an example of a mysqld instance that’s really, really frozen up:

bt-aggregate -4 samples/backtrace.txt | head -n12
2396 threads with the following stack trace:
        #0  0x00000035e7c0a4b6 in …