A lot of times I’m looking at several time-series samples of numbers embedded in free-form text, and I want to know how the numbers change over time. For example, two samples of SHOW INNODB STATUS piped through grep wait might contain the following: Mutex spin waits 0, rounds 143359179688, OS waits 634106844 RW-shared spins 1224152309, OS waits 38278807; RW-excl spins 2432166425, OS waits 35264871 Mutex spin waits 0, rounds 143386303439, OS waits 634292093 RW-shared spins 1224197048, OS waits 38281423; RW-excl spins 2432347936, OS waits 35271423 How much have the numbers changed in the second sample?

Spinn3r is growing fast. Time to hire another engineer. Actually, we’re hiring for like four people right now so I’ll probably be blogging more on this topic.

My older post on this subject still applies for requirements.

If you’re a Linux or MySQL geek we’d love to have your help.

Did I mention we just moved to an awesome office on 2nd and Howard in downtown SF?

…

MySQL Full Text Search Limitations

Suppose you have a MyISAM table containing a column with a full text index. This table starts to grow to a significant size (millions of rows) and gets updated fairly frequently. Chances are that you’ll start to see some bottlenecks when accessing this table, since without row level locking, the reading and writing operations will be blocking each other.

A solution that many people would suggest right away is to use the master for writes and a slave for reads, but this only masks the problem, and it won’t take long before enough read traffic on the slave starts causing slave lags.

Why Sphinx?

The main difference between the Sphinx search engine and other alternatives is its close integration with MySQL. For example, it can be used as a storage engine.  In this way, Sphinx’s impact on existing application code …

Recently while we were building a slave with a newer version of MySQL 5.1 from an InnoDB Hot backup, the following error occurred when we ran mysql_upgrade:

mysql.time_zone                                    OK
mysql.time_zone_leap_second                        OK
mysql.time_zone_name                               OK
mysql.time_zone_transition                         OK
mysql.time_zone_transition_type                    OK
mysql.user                                         OK
Running 'mysql_fix_privilege_tables'...
ERROR 13 (HY000) at line 311: Can't get stat of './mysql/general_log.CSV' (Errcode: 2)
ERROR 13 (HY000) at line 316: Can't get stat of './mysql/slow_log.CSV' (Errcode: 2)
FATAL ERROR: Upgrade failed

The problem is that in MySQL 5.1, it is possible to log the slow query log and general log to tables in the mysql schema (source: Selecting General Query and Slow Query Log Output Destinations). These tables are …

UPDATE: The final vote is in and a winner has been declared, with Matt Asay and his arguments for the GPL taking the prize. You can see the debate or follow links to the other judges’ votes and thoughts here.

This is my assessment as a judge of the recent open source license debate held by the FOSS Learning Centre. We’ll have to begin with some qualifications and definitions, starting with the fact that there is no ‘best’ open source software license. Still, a star-studded open source software panel provided a lively, informative debate on the merits of some top open source licenses. For that, I congratulate and thank the panelists, Mike Milinkovich from the Eclipse Foundation arguing for the Eclipse Public License, Matt Asay of Alfresco arguing in favor of the GPL and David Maxwell from Coverity arguing for …

With all of the discussions over the past years about MySQL Replication vs. DRBD (where the “vs.” part is in fact grossly misled of course — they are two technologies that complement each other quite well), here’s one with a slightly different angle: does it make sense to roll your own cluster manager around MySQL Replication, or is it smarter to plug into an existing, proven cluster architecture?

You’ll expect my own view to be fairly well defined, and it is. …

We all knew that we are risking with MMM. Risking, and placing availability as a more important like consistency.  But non of us can risk loosing data forever but we show using it, regarding to our conversations think:  "I can fix my data later on, but I can’t turn back time and prevent the downtime. (Pascal Hofmann@xaprb.com)".

As I wrote before about staying online, now let me write about how to stay consistent.

We all know, mmm is not like a key of salvation, but its getting close to it . While MySQL doesn't support multi-master-slave environments from it's source code, we will sleep badly wondering on the safety of our precious databases.

But its not just about MMM, a few days ago we ran in to a well known InnoDB "feature". Its about the auto increment counter determination on restart. InnoDB try to count the next auto increment value on MySQL restart what can screw up things in the replication as in your …

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 …