Baron recently wrote about sending the query to the data looking at distributed systems like Cassandra. I want to take a look at more simple systems like MySQL and see how we’re doing in this space.

It is obvious getting computations as closer to the data as possible is the most efficient as we will likely have less data to work with on the higher level in this case. Internally MySQL starts add optimizations which help in this regard, such as Index Condition Pushdown which allow storage engine to do most rudimentary data filtering improving efficiency.

The more important case though is the Application – Database interaction. Modern applications often have quite complicated logic which might not map to SQL very well. Framework and the practices developers follow can only add to this problem. As results Application may be issuing a …

…

…

There is a Debian MariaDB plan from the MySQL package team. There is good news as on September 30 2013, the upload to Debian unstable is complete with MariaDB 5.5 (5.5.32). It’s now only a matter of time before this becomes available in Debian. 

Its great to see the work of Otto Kekäläinen finally make it into Debian. I would say this has been in the works for seven months. Much thanks to James Page (Canonical) and Clint Byrum (HP, Debian Developer) for reviewing and uploading.

This joins the …

On October 15 and 16 I'll take the ferry to be at the MySQL NoSQL Cloud conference in Buenos Aires, and the schedule looks really nice so far. I think it's a great opportunity for people in this region to get up to date with what's going on in the MySQL ecosystem, and to have good discussions with members of the community that aren't usually around here.

I still haven't decided my complete agenda, as in some cases it's difficult to pick one track and miss the other one, but for now, here are some highlighted sessions I'm definitely attending:

Related posts:

1. Presenting at Percona Live NY 2012 I’ll be attending Percona Live NY 2012 next month, co-presenting...
2. Using MySQL sandbox for testing …

The “Too many connections” problem is a common issue with applications using excessive permissions (and those that grant said global permissions). MySQL will always grant a user with SUPER privileges access to a DB to investigate the problem with a SHOW PROCESSLIST and where you can check the limits. I however found the following.

mysql> show global variables like 'max_connections';
+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 2000  |
+-----------------+-------+
1 row in set (0.00 sec)

mysql> show global status like 'max%';
+----------------------+-------+
| Variable_name        | Value |
+----------------------+-------+
| Max_used_connections | 6637  |
+----------------------+-------+
1 row in set (0.00 sec)

How can the max_used_connection exceed max_connections? This is possible because you can dynamically change max_connections in a normal MySQL environment. However …

I’ve previously shared my excitement over the coming Oracle Certified Professional exams for MySQL 5.6 (both Developer and DBA), and I’m putting my (employer’s) money where my mouth is – I’ve registered to sit for the DBA exam in early November (some test sites have limited opportunities; interested candidates should consider booking now).  Here’s why I think others should do the same:

Low cost

During the beta period (through December 14), the cost of the exam is only $50 USD.  That’s barely more than the cost of a book or study guide these days, and a significant savings from the normal exam prices.

Full certification

Those who pass the exam will be given a full certification – not some lesser “beta certification.”  There’s no distinction between those who …

We had a Galera Cluster support case recently. The customer was drenched in tears because his Galera Cluster did not work any more and he could not make it work any more.

Upsss! What has happened?

A bit of the background of this case: The customer wanted to do a rolling-restart of the Galera Cluster under load because of an Operating System upgrade which requires a reboot of the system.

Lets have a look at the MySQL error log to see what was going on. Customer restarted server with NodeC:

12:20:42 NodeC: normal shutdown --> Group 2/2
12:20:46 NodeC: shutdown complete
12:22:09 NodeC: started
12:22:15 NodeC: start replication
12:22:16 NodeC: CLOSED -> OPEN
12:22:16 all  : Group 2/3 component all PRIMARY
12:22:17 NodeC: Gap in state sequence. Need state transfer.
12:22:18 all  : Node 1 (NodeC) requested state transfer from '*any*'. Selected 0 (NodeB)(SYNCED) as donor.
12:22:18 NodeB: Shifting SYNCED -> DONOR/DESYNCED (TO: …

FromDual has the pleasure to announce the release of the new version 1.0 of its popular multi-instance MySQL Environment MyEnv.

Thanks to the countless feedback of many big customers and the community we finally feel ready to publish version 1.0. A major step forward from the last version 0.4 (dated March 2011) and not published version 0.5 (dated August 2013).

What is MyEnv?

MyEnv is a CLI environment for operating multiple MySQL instances on the same server. If you are using mysqld_multi or/and if you have set-up multiple mysqld instances on the same machine you should really have a look at MyEnv.

If you consider to consolidate your MySQL databases on one machine but if you do not want to pack everything in one instance you are a candidate for MyEnv as well...

You can download MyEnv from here.

In …

To bring to attention those who will be in Tokyo, Japan or Buenos Aires, Argentina:

1. MariaDB/MySQL Community Event – 9 October 2013 – Tokyo, Japan. Come see Michael Carney, Ivan Zoratti, Kentoku Shiba (creator of the SPIDER storage engine) and Colin Charles at this event. It is from 12.30pm – 8pm, and includes evening cocktails to some extent. It should be free to attend.
2. MySQL NoSQL Cloud – 15-16 October 2013 – Buenos Aires, Argentina. This is the second such conference happening in Buenos Aires, and this time there are plenty of speakers who didn’t make it around the first time. Cost is nominal.

Related posts:

1. …