Scary movies for teenagers and database administration tasks share some common traits. Usually, the movie starts with a group of teens making unwise choices. Maybe you, as a DBA, are no longer a teenager, but you shouldn’t underestimate your ability to do the same.

$ sudo su -
Darrera entrada: ds jun 2 14:43:53 UTC 2018 des de a a pts/0
[root@mysql ~]# cd /var/lib/mysql
[root@mysql mysql]# df -h .
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00 38G 35G 3G 92% /
[root@mysql mysql]#

Back to the movie…today is just another regular day. Checking Jira (or whatever your ticketing system is), answering emails and phone calls. Maybe a couple of meetings. And in the meantime, you will perform some critical tasks on the most important systems for your company. Just the usual stuff!

[root@mysql mysql]# ls -l *.log
ls: cannot access *.log: No such file or directory
[root@mysql mysql]# ls -l *log*
-rw-r-----. 1 …

There was an interesting but hard to read post on StackOverflow about how 'insert select delete' data from a MySQL JSON data type column.  The first line of the writer's problem is a little confusing '
In order to record user mac_address and count mac_address to restrict user login's pc or notebook to control user available max for example (it's work)' but the examples reveled more about what was desired. The idea was to track MAC address used by various users and the author of the question was wondering how to up data a JSON Array of values with JSON_INSERT.  INSERT is for inserting and the better choice would be JSON_ARRAY_APPEND or JSON_ARRAY_INSERT.    But what caught my eye was the second question: Select sql command for json column ? could be …

Percona announces the release of Percona Toolkit 3.0.11 on July 6, 2018.

Percona Toolkit is a collection of advanced open source command-line tools, developed and used by the Percona technical staff, that are engineered to perform a variety of MySQL®, MongoDB® and system tasks that are too difficult or complex to perform manually. With over 1,000,000 downloads, Percona Toolkit supports Percona Server for MySQL, MySQL®, MariaDB®, Percona Server for MongoDB and MongoDB.

Percona Toolkit, like all Percona software, is free and open source. You can download packages  …

In the last few days, there has been information released about yet another alleged data leak, placing in jeopardy “…[the] personal information on hundreds of millions of American adults, as well as millions of businesses.” In this case, the “victim” was Exactis, for whom data collection and data security are core business functions.

Some takeaways from Exactis

Please excuse the pun! In security, we have few chances to chuckle. In fact, as a Security Architect, I sigh deeply when I read about this kind of issue. Firstly, it’s preventable. Secondly, I worry that if an organization like Exactis is not getting it right, what chance the rest of the world?

As the Wired article notes the tool https://shodan.io/ can be revealing and well worth a look. For example, you …

I found this old article that shows how to setup
highly available DNS/DHCP servers using MySQL Cluster.

It uses 4 machines with 4 replicas, it describes how to do it with MySQL Cluster 7.3,
obviously today it would make more sense to use 7.5 or 7.6. In this case an extension
would be add ndb_read_backup=on to my.cnf to ensure that all MySQL servers in the
clusters reads the local copy rather than going over the network to read from another
replica.

Another tool that I found and discussed in my book on MySQL Cluster that uses
NDB for DNS and DHCP is Kea, here is an article describing how to setup Kea using NDB.

Now that MySQL 8.0 GA is out for almost 3 months, let’s see the status of how it’s integrated with Drupal, a very popular CMS using MySQL.

For people having already a Drupal site and that wants to upgrade to MySQL 8.0, please check this post.

Now if you want to use MySQL 8.0 with a fresh new Drupal 8, let’s have a look how does that work.

Drupal 8.5

Drupal 8.5.5 is the latest available stable release from July 4th 2018.

There is no notes about supporting MySQL 8.0. So let’s try it.

…

In some cases, the server creates internal temporary tables while processing statements. These tables could be stored in memory or on disk – the first option is preferred but there exist some limitations. One of such restrictions was presence of TEXT or BLOB columns in the table; as in-memory storage engines (MEMORY and TempTable) did not supported these types server had to use the on-disk engine (InnoDB or MyISAM).…

How serious are companies and the people who support their databases about security? Not serious enough it seems. How many databases are running with users with excessive privileges, OS privileges elevated? What about securing via encryption your network traffic both … Continue reading →

This post is mainly inspired by findings from the previous testing of MySQL 8.0 on TPCC workload(s) and observations from IO-bound Sysbench OLTP on Optane -vs- SSD. But also by several "urban myths" I'm often hearing when discussing with users about their IO-bound OLTP performance problems :
Myth #1 : "if I'll double the number of my storage drives -- I'll get x2 times better TPS !"

• this was mostly true during "HDD era", and again..
• (ex.: a single thread app doing single random IO reads from a single HDD will not go faster by doing the same from 2x HDD -- similar like single thread workload will not run faster on 8CPU cores -vs- 2CPU cores, etc.)
• all depends …

If you are going to be using InnoDB tables and if you plan to have innodb_file_per_table enabled, then your best option would probably be to use the CREATE TABLE statement’s “DATA DIRECTORY” option, so that you can place a table outside the data directory.
From the MySQL documentation:

DATA DIRECTORY, INDEX DIRECTORY

For InnoDB, the DATA DIRECTORY=’directory’ option allows you to create InnoDB file-per-table tablespaces outside the MySQL data directory. Within the directory that you specify, MySQL creates a subdirectory corresponding to the database name, and within that a .ibd file for the table. The innodb_file_per_table configuration option must be enabled to use the DATA DIRECTORY option with InnoDB. The full directory path must be specified. See Section 14.7.5, “Creating File-Per-Table Tablespaces Outside the Data Directory” for more information.

…