FromDual TechFeed (en)

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hi Roland,

Ups! It seems like I did not look into it well enough… :( Thanks for your hint!

Just found the [http://www.mysqludf.org/ UDF repository] on your site. Great stuff…

Windows? What is this? No honestly: I did not try this out. There is no such system close to me nor have I a Win compiler or such stuff… Sorry!

I really like this new toy (for me) called UDF. So I try to provide some more, hopefully useful, functionality.

The newest extension I like is the possibility to write to the MySQL error log through the application. Oracle can do that since long. Now we can do this as well…

A list of what I have done up to now you can find here:

• Query and change InnoDB spin_wait_delay: udf_spin_wait_delay-5.1.30-linux-i686-glibc23.so (md5 807c6bc09b5dc88a8005788519f2483a, BIN … kbyte)
• Send message to the …

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

I was told that spin_wait_delay is exposed to public with the InnoDB pluggable storage engine 1.0.4. Seems I have to look for an other hidden variables now. :)

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hi Papagnome,

You are absolutely right, UDF’s came in in 3.23 already (I was told). What was in my mind was more the pluggable stuff. This feature is very nice an pretty new. But somehow I did not manage to express what I wanted to… :)

Regards, Oli

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hi Mark,

Thanks a lot for your feedback. And how is the correct way to make it version IN-dependent and thus better portable?

In one of my previous posts I was writing about how to read other processes memory
[ 1
]. As an example I tried to get the value of the hard coded MySQL internal InnoDB variable spin_wait_delay (srv_spin_wait_delay).

In this example we were using gdb or the operating system ptrace function to retrieve this value. This method has the disadvantage that it is pretty invasive.

When I was working on a customer support case I had the idea to solve this by the much less invasive method of User-Defined Functions …

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Andrew pointed me to the following blog entry of Brian: [http://krow.livejournal.com/481313.html Daemon Example (deamon plugin)]

Thanks!

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hi Björn,

Thanks a lot for you post. Much better than mine! :)

Shinguz

Recently a colleague at Sun was asking me if MySQL can tell him to determine if we are currently in summer time or winter time. He was doing some data analysis of his house where he has installed solar panels.

I am not aware of what he wants to do exactly, but possibly he wants all the data in solar time. So UTC could help him because UTC does not change much over time.

Next thing which came to my mind is, that possibly the good place to do such mathematical calculations is the application code and not the …

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

A colleague pointed out that I was missing some information:

The operative worklog task is WL#2360 and its dependencies, WL#4034 is a raw-idea bin item of no current significance.

The complete specification of the performance schema can be found here:

[http://forge.mysql.com/worklog/task.php?id=2333 WL#2333: SHOW ENGINE … LOCK STATUS] [http://forge.mysql.com/worklog/task.php?id=2360 WL#2360: Performance Schema] …

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hi Morgan,

Do not get this. With the script read_process_memory.sh you can sample at a specific interval with a timestamp in the record and write a *.csv. That must be ideal for Cacti or any other monitoring/graphing tool, is it not? You could even extend it to write directly to a database…

Please elaborate a bit more your concern.

As you probably have experienced yet MySQL does not always provide all internal information as you might want to have them and as you are used to have from other RDBMS.

MySQL plans to improve this implementing the/a performance schema and its probably already partly done in MySQL 5.4. But who knows when this will be finished and what it contains at all…

What is not provided to me I want to gather myself… But how? Other RDBMS provide interfaces to attach applications directly to their memory to …

The following summary shows my personal understanding of MySQL 5.1 licenses, packages and products. It does not necessarily reflect 100% the way MySQL understands it. But after all the discussions I hope it is as close as possible to the reality:

MySQL Embedded Database Server

(Download → OEM Software)

Classic  (OEM license, -MEM -InnoDB)
Pro      (= Classic +InnoDB)
Advanced (= Pro +Partitioning)

MySQL Community Sever

(Download → Download)

Community (GPL, -NDB)

MySQL Enterprise Server

(Download → …

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hey guys,

Have a look at the addendum. I have updated it.

Regards, Oli

This week we had a very interesting problem at a customer: They complained, that their MySQL Cluster takes about 1 hour for a --initial start-up. After some tuning on the hardware and the config.ini they brought it down to around 40 minutes. But this is still unacceptable long…

This sounds a little strange to me. But let us have a look at their config.ini first. It looked more or less like the following (which is already tuned!):

#
# config.ini
#

[NDB_MGMD DEFAULT]
DataDir                      = …

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hi Baron

Hmmm. Did not know about it. But to be honest: I did not yet have time to look at all the nice stuff from your Maatkit and all the cool Google Patches and OurDelta etc… :-(

But thanks for the hint!

[http://www.blogger.com/profile/11195863756524022642 Shinguz] said…

Hi Willy

Yes. MySQL circular replication usually works fine (technically). I hope you have a good concept cleaning it up again when it some how messes up!

We usually recommend customers to be very very careful with this kind of replication!

Regards Oli

Introduction

One of the features that make MySQL so great is its easy replication set-up. If you are experienced and know-how to do it, it takes you about 15 minutes to set-up a slave. What you have in the end is a replication from one master to one or several slaves. So you can build a top-down data stream pyramid and spread your data on many slaves.

From time to time some customers are asking for the other way: Many masters replicating to one slave (which is also called multi-source replication). For …

When I set-up a MySQL HA environment for customers I usually do some final failover tests after configuring the whole beast.

To check if the application behaves like expected I always run my little test application (test.sh) from the server(s) where the customers application runs. It displays “graphically” how the application behaves and you can show to the customer immediately what is going on…

Make sure, that you point it to the virtual IP (VIP) or the load balancer (LB).

It was really …

Das dreieckige Rad hat gegenüber dem viereckigen einen gewaltigen Vorteil: Ein Rumms weniger pro Umdrehung!

Translation:

The triangular wheel has one enormous advantage over the quadrangular: One knock less per revolution!

Maybe not new, but I have not heard it yet and I love it. It was about reinventing functionality in a well known product…