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Displaying posts with tag: Databases (reset)
My MySQL bugs and feature requests

My MySQL bugs is a list I recently created and intend to keep up to date with issues I have seen.

First Madrid MySQL Users Group scheduled for the 4th July

As mentioned here and after talking to a few people we have created a meetup page, http://www.meetup.com/Madrid-MySQL-users-group/ and proposed the first meeting on Thursday, 4th July. If you are interested and in the area come along and say hello. It should be interesting to see a few others who work in the field.  If you can let us know you are coming so we have an idea of how much interest there is.

Announcing the MySQL Plugin for New Relic

Many application developers would know of New Relic. A SaaS performance and monitoring tool targeted towards your web application monitoring including PHP, Ruby, Java, .Net, Python and Node.

With the release today (June 19, 2013) of the New Relic Platform, custom monitoring of data stores including MySQL are now possible. Try it now free. This link will provide you a free standard account (no cost, no billing details necessary), that enables you to perform application monitoring, server monitoring, MySQL instance monitoring and monitoring of many other products via many plugins.

Over the next few posts I will be discussing some of the design decisions I made for this MySQL plugin. New Relic has certain …

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On operating system upgrades and a packager’s nightmare

A fairy tale

Once upon a time I did an operating system upgrade, a minor one that should do no harm, but just get me up to date by fixing any bugs in the version I had been using. It seemed like a good idea.

All seemed to be fine. I use a package provided by an external vendor and not the one produced by the operating system provider as this vendor provides a newer version of the package and I need that. The vendor has to make his package fit in the os environment his package is built for and normally does a pretty good job.

I use automation to build my systems and when I built a new one some issues appeared. Related to the new version of the OS the provider had enhanced one of his packages and the installation pulled in new dependencies. The install of the external package I use then broke as it conflicted with the new dependency provided by the OS.  While a workaround is possible: uninstall …

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2013 SkySQL and MariaDB Solutions Videos Are Online!

I do not recall seeing an announcement about it, but I went looking for the videos today and lo and behold, they were up! Forgive me if I missed a post about it….but if you also missed it, here they are:

2013 SkySQL and MariaDB Solutions Day for the MySQL Database videos

Madrid MySQL Users Group worth creating?

I’m interested in meeting up and sharing experiences about using MySQL and managing MySQL servers with people here locally in Madrid. I had a quick look around and could see no MySQL user groups locally, so it might be nice to create such a group and exchange ideas over a beer, coffee or cola every once in a while. If you’re in Madrid and are interested please let me know. I’ve created a temporary  email address: madrid-mysql-users-2013 AT wl0.org (careful with the domain), which you can contact me on to confirm an interest.  Oh and I’d expect these meet ups to be in Spanish, but that’s not a requirement.

Estoy interesado en reunirme y compartir experiencias sobre el uso de MySQL y administración de servidores de MySQL con la gente aquí en Madrid. He echado un vistazo en Internet y no he visto ningún grupo de usuarios de MySQL a nivel local, por lo que sería bueno crear un grupo e intercambiar ideas mientras tomamos …

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MySQL Quirk with Not Null Columns and Default Values

One of my coworkers came across a strange quirk in MySQL with default values for not null columns. Take a look at this table:

Create Table Posts
(
     PostID Int Auto_Increment Primary Key
    ,Title Varchar(30) Not Null
    ,Body Text Not Null
    ,Summary Varchar(25) Not Null Default ''
);

Note the column Summary that is marked not null but has a default value of an empty string. Now, try to insert a null value into this column.

Insert Into Posts (Title, Body, Summary) Values ('A title', 'A body', null);

You’ll get this error:

ERROR 1048 (23000): Column 'Summary' cannot be null

Now, using an extended insert (where you specify multiple rows in an insert statement), we can insert the same data and it will complete successfully, although there will be warnings.

Insert Into Posts (Title, Body, Summary) Values ('A title', 'A body', null), ('2nd body', '2nd body', null);

Query OK, 2 rows …
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A Different Spin On the max_allowed_packet Problem

Back in November, I filed MySQL bug 67448, talking about a different type of max_allowed_packet problem.

See, an application had put data into the database, but could not retrieve it without getting max_allowed_packet. With the help of some really smart community folks (named Jesper Hansen, Brandon Johnson and Shane Bester), we determined that MySQL actually has 2 different max_allowed_packet settings: client and server.

When you change the max_allowed_packet variable, you are changing the server variable if it is in [mysqld] and the client variable if it is in [client] or [mysql] or whatever client you have. As far as we can tell, there’s no way to actually view what the client variable is, as looking at both the session and global max_allowed_packet variable shows you the server variable.

If max_allowed_packet is not set by the client, it defaults to …

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ulimits and upgrading from Oracle MySQL 5.0 to Percona patched MySQL 5.1

After upgrading to Percona’s patched MySQL 5.1*, end users were having connectivity problems, and reporting errors such as:

OperationalError: (2003, "Can't connect to MySQL server on 'db-amo-ro' (110)")

TimeoutError: Request timed out after 5.000000 seconds

OperationalError: (1135, "Can't create a new thread (errno 11); if you are not out of available memory, you can consult the manual for a possible OS-dependent bug")

We had these same problems a while back, before increasing ulimit settings in /etc/sysconfig/mysqld. Oracle’s MySQL startup script specifically sources this file:

[ -e /etc/sysconfig/$prog ] && . /etc/sysconfig/$prog

However, we saw these errors again when we upgraded to Percona’s MySQL 5.1. At first we thought that it was because Oracle’s startup script is /etc/init.d/mysqld and …

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MySQL User Group Video – Determinism and Databases

The May Boston MySQL User Group featured John Hugg of VoltDB talking about determinism and databases. I have uploaded the hour-long video to http://www.youtube.com/watch?v=mTDLyRauJtw. Seasoned MySQLers will nod their heads because the problems described are familiar, and those who are not exactly sure what “determinism and databases” means will learn a lot.

Enjoy!

(As always, videos are free on YouTube with no login or attempt to solicit your e-mail address or any other information)

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