Notes/errata/updates for Chapter 9:
See the official book errata at http://tahaghoghi.com/LearningMySQL/errata.php – Chapter 9 includes pages 297 – 350.

In the fourth paragraph of this chapter, starting with “Most applications don’t need superuser privileges for day-to-day activities” they give you some reasons why you want to create users without the SUPER privilege. There are better reasons than the book gives, which are at the MySQL Manual page for the SUPER privilege.

In the section “Creating and Using New Users” (p. 300) they say “There’s no limit on password length, but we recommend using eight or fewer characters because this avoids problems with system libraries on some platforms.” You should ignore this, this book …

So, recently we had a runaway query eat up all sorts of temporary table space on our machines. Several machines had several terabytes in their ibtmp1 file after this happened. So I set out to find out more about why the InnoDB temporary tablespace is used, why it is better than using regular files, which was what was used prior to MySQL 5.7, and how to make sure that runaway queries do not end up filling up disk space.

Unfortunately, the manual does not go into why ibtmp1 is better than one file per temporary query, which disappears once the query ends. There are a few sections to look into:

Temporary Table Undo Logs – has one paragraph that states that these are the undo logs for temporary tablespaces. Given that these are undo logs, my guess is that this makes MySQL more crash-safe. But that is just a …

Notes/errata/updates for Chapter 7:
See the official book errata at http://tahaghoghi.com/LearningMySQL/errata.php – Chapter 7 includes pages 223 – 275.

Supplemental blog post – ORDER BY NULL – read the blog post and the comments!

GROUP BY and HAVING examples – Supplemental blog post. The example of HAVING in the text shows a use case where HAVING is the same function as WHERE. This blog posts shows examples of HAVING that you cannot do any other way.

In the section called “The GROUP BY clause”, on pages 231-232, the book says:
“you can count any column in a group, and you’ll get the same answer, so COUNT(artist_name) is the same as …

Prior to MySQL 5.7 client communications with a MySQL instance were unencrypted by default. This plaintext capability allowed for various tools including pt-query-digest to analyze TCP/IP traffic. Starting with MySQL 5.7 SSL is enabled by default and will be used in client communications if SSL is detected on the server.

We can detect and confirm this easily with the ngrep command.

Default client connection traffic (5.6)

On a MySQL 5.6 server we monitor the default MySQL port traffic.

mysql56$ sudo ngrep -d eth1 -wi -P ' ' -W single -l port 3306
interface: eth1 (192.168.42.0/255.255.255.0)
filter: ( port 3306 ) and ((ip || ip6) || (vlan && (ip || ip6)))
...

We connect to this server using TCP/IP.

host$ mysql -uexternal -p -h192.168.42.16
mysql56> select 'unencrypted';

We can observe the communication to and from the server (in this example 192.168.42.16) is …

Notes/errata/updates for Chapter 6:
See the official book errata at http://tahaghoghi.com/LearningMySQL/errata.php – Chapter 6 includes pages 179 – 222.

Other notes:
At the end of the “Creating Tables” section (p.183-4), it says “We like using the underscore character to separate words, but that’s just a matter of style and taste; you could use underscores or dashes, or omit the word-separating formatting altogether.” While this is true, beware of using a dash, because MySQL will try to interpret “two-words”, thinking – is a minus sign. I recommend avoiding dashes for this reason (even though the book does this on page 215).

At the end of the “Collation and Character Sets” section (p.186), it says “When you’re creating a database, you can set the default character set and sort order for the database and its …

Join Percona’s Chief Evangelist, Colin Charles as he presents Databases in the Hosted Cloud on Wednesday, October 4, 2017, at 7:00 am PDT / 10:00 am EDT (UTC-7).

Register Now

Today you can use hosted MySQL/MariaDB/Percona Server for MySQL/PostgreSQL in several “cloud providers” as a database as a service (DBaaS). Learn the differences, the access methods and the level of control you have for the various public databases in the hosted cloud offerings:

• Amazon RDS including Aurora
• Google Cloud SQL
• Rackspace OpenStack DBaaS
• Oracle Cloud’s MySQL Service …

Welcome to another post in our series of interview blogs for the upcoming Percona Live Europe 2017 in Dublin. This series highlights a number of talks that will be at the conference and gives a short preview of what attendees can expect to learn from the presenter.

This blog post is with Bernd Erk, CEO of Icinga. His talk is titled Monitoring Open Source Databases with Icinga. Icinga is a popular open source successor of Nagios that checks hosts and services, and notifies you of their statuses. But you also need metrics for performance and growth to deal with your scaling needs. Adding conditional behaviors …

Want to learn or refresh yourself on MySQL? MySQL Marinate is the FREE virtual self-study group is for you!

MySQL Marinate quick links if you know what it is all about.

This is for beginners – If you have no experience with MySQL, or if you are a developer that wants to learn how to administer MySQL, or an administrator that wants to learn how to query MySQL, this course is what you want. If you are not a beginner, you will likely still learn some nuances, and it will be easy and fast to do. If you have absolutely zero experience with MySQL, this is perfect for you. The first few chapters walk you through getting and installing MySQL, so all you need is a computer and the book.

The format of a virtual self-study group is as follows:
Each participant acquires the same textbook ( …

The website or mobile app is the storefront for participating in the modern digital era. It’s your portal for inviting users to come and survey your products and services. Much attention focuses on front-end development; this is where the HMTL5, CSS, and JavaScript are coded to develop the landing page that everyone sees when they visit your site.

But the real magic happens on the backend. This is the ecosystem that really powers your website. One writer has articulated this point very nicely as follows:

The technology and programming that “power” a site—what your end user doesn’t see but what makes the site run—is called the back end. Consisting of the server, the database, and the server-side applications, it’s the behind-the-scenes functionality—the brain of a site. …

In this article, we will show you how to configure remote and secure connections for MySQL on Ubuntu 16.04 VPS.  ...

Read moreHow to configure remote and secure connections for MySQL on Ubuntu 16.04

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