In this previous Blog I described an example on how to build a Custom Object in MONyog. But there is one problem you may encounter and that is, that when querying Information_Schema and Performance_Schema, it can sometimes be difficult or impossible to be sure to have a unique column (or a unique set of columns)  in the result set as neither of those generally guarantee uniqueness with a(ny) subset of columns. And a unique column (or a unique set of columns) is required for a MONyog Custom SQL Object.

A common way to add a unique row-identifer to a result set is like this (note the use of  ”assignment operator” (“:=”) as different from “comparison operator” (“=”) ):

SET @t = 0;
SELECT @t:=@t+1 AS uniq, id FROM thetable ORDER BY uniq;

.. but using this is …

A quick reminder. I’m speaking on two MySQL meetups in North Carolina this week. Tuesday,Feb 21 on Raleigh MySQL/PHP Meetup and when Wednesday, Feb 22 on Charlotte Queen City PHP Note the last meetup date has changed, it was originally planned for February 23 but had to be rescheduled due to conflicts.

SkySQL recently announced the Solutions Day for the MySQL Database to be held on the 13'th of April at the Hyatt Regency Santa Clara.

At this conference you will, for the first time in 3 years, again see David Axmark and me on stage on a keynote about the state of MySQL and MariaDB and how we envision the future of these products!

There will also be a lot of tech talks about MySQL and MariaDB from the original MySQL creators as well as on related products from other people in the MySQL / MariaDB community.

Do register in advance, I look forward to seeing you there!

This day will be free for anyone to participate. There will also be free black vodka later in the …

“Legacy MySQL does not scale well on a single node, which forces granular sharding and explicit application code changes to make them sharding-aware and results in low utilization of severs”– Dr. John Busch, Schooner Information Technology A super-set of MySQL suitable for Big Data? On this subject, I have interviewed Dr. John Busch, Founder, Chairman, [...]

Replication just stopped in one Slave server with error: The table xtable is full which means no more records are permitted to insert in this table by MySQL and hence this has broken the replication.

I checked that xtable is having storage engine as Memory. In such tables, the max. no. of records you can insert is controlled by variable max_heap_table_size. When checking the size of this variable, I found that this is having default value:

mysql> show variables like 'max_heap_table_size';
+---------------------+----------+
| Variable_name       | Value    |
+---------------------+----------+
| max_heap_table_size | 16777216 |
+---------------------+----------+
1 row in set (0.00 sec)

So we need to increase the value of this variable and then issue Alter Table command to make it effective. Also do not …

I am a minimalist at heart, and I love command line interfaces and text files.

However, I’m also pragmatic, and so for a long time my blog has been powered by Wordpress, which made it relatively easy to manage content and design. I just didn’t want the hassle of maintaining something myself.

Somewhere along the way recently I stumbled across Jekyll, and the idea of generating a static site from templates.

I’d seen a few sites I liked the look of, and I loved the idea of simplifying my site (and editing posts in vim!), and so the end result is the site you see now. The theme is based on skim.la’s site.

I pondered implementing something like disqus for comments, but honestly I get so few proper responses, compared to the hundreds and hundreds of spam …

In response to the release of our new MySQL monitoring plugins on Friday, one commenter asked why the new Nagios plugins don’t use caching. It’s worth answering in a post rather than a comment, because there is an important principle that needs to be understood to monitor servers correctly. But first, some history.

When I wrote a set of high-quality Cacti templates for MySQL a few years ago (which are now replaced by the new project), making the Cacti templates use caching was important for two reasons:

1. Performance. Cacti runs some of its polling processes serially, so if each graph has to reach out to the MySQL server and retrieve a bunch of data, the polling can take too long. I’ve seen cases where a Cacti server that’s graphing too many MySQL servers doesn’t …

Right after you finish your installation, you need to execute the below command from the shell.

mysql_secure_installation

By executing this command, mysql will remove all anonymous access in your database including the test database. It will also require you to set password for root account as well if you want remote access to your database.

Taxonomy upgrade extras: High Availabilitymysqlconsultingclusterinnodbfromdualsupportgaleracodershipmysql-supportmysql-consulting

Helsinki, …

MariaDB 5.3 has reached the release candidate milestone, and the 5.3 version promises a lot of new features and optimization (i.e in optimizer http://kb.askmonty.org/en/what-is-mariadb-53#query-optimizer). No surprise I wanted to check how all improvements affect general performance.

So I why don’t we run old good sysbench benchmark.

For the benchmark I took:

• HP ProLiant DL380 G6 box
• sysbench multitables oltp rw workload, 16 tables, 500mil rows each, total datasize about 30GB
• working threads from 1 to 256
• Versions: MariaDB 5.3.4, MySQL 5.5.20
• Data is stored on RAID10 HDD partition
• Like in all my recent benchmarks, I make throughput measurements each …