Category: Article

MySQL 8.0 joins Google Cloud SQL

This is the announcement blogpost and this is my overview taken from medium:

The one where MySQL 8.0 lands on Google Cloud SQL

Ada Doglace and Lily Grace (lilygrams)
Ada Doglace and Lily Grace (lilygrams). Photo by Anthony Ferrara.

There are many things that makes me happy. Puppies (see picture), food, wine and databases… (not particularly in that order). And things that makes me even happier such as a well designed schema and proper usage of ORM (Object Relational Mapping).

MySQL was the database I used to love to hate. It grew on me and the fact that long strides were made to make it more consistent and more modern kept me away from using other open source databases on a daily basis for my projects. And with grand expectation and admiration I am proud of the Cloud SQL team for achieving this milestone:

Today we are making available MySQL 8.0 on Cloud SQL. It’s not just a new version inside our managed databases portfolio, but it also comes with all Cloud SQL capabilities such as Automatic Storage Increase, High Availability, Cross-region Replication and PITR (point in time recovery). And best yet: It’s not a beta, it’s a GA launch! See the announcement.

You can start using today from scratch or migrate an existing MySQL database to Cloud SQL; as a way to minimize downtime you can use the External Replication feature from your Google Cloud Console or via the gcloud command-line tool.

MySQL 8.0 has a huge list of new features, and you can do a range of new operations and querying. You can even do silly things like Fibonacci sequence using SQL (it is true!), traverse a Binary Tree or even do the old fizz-buzz:

WITH RECURSIVE fizz_buzz (sequence, modulo_3, modulo_5) AS (
  SELECT 1, CAST('' AS CHAR(4)), CAST('' AS CHAR(5))
  UNION ALL
  SELECT sequence + 1,
         IF(MOD(sequence + 1, 3) = 0, 'Fizz', ''),
         IF(MOD(sequence + 1, 5) = 0, 'Buzz', '')
  FROM fizz_buzz
  WHERE sequence < 100
)
SELECT
       IF(CONCAT(modulo_3, modulo_5) = '', sequence, CONCAT(modulo_3, modulo_5)) AS fizzbuzz
FROM fizz_buzz;

On a more serious note, and enterprise worthy, you can now avoid sub-queries (or other N+1 problems), have better access control, and use Window Functions. There are plenty of new stuff, and this is a small list of talks on MySQL 8.0 I gave since the preview versions in 2017. One of my favorites is the following:

phpDay about MySQL 8.0 Features

At Google we define anyone that uses a keyboard to work on a technical aspect of a product a Technical Practitioner. It is a wider definition, however more inclusive to the DBAs, DevOps and SysAdmins alike.

My particular goal has always been to help the day-to-day practitioner do things they wouldn’t imagine their database was capable of. This is why I have the Office Hours. This is why I do those talks and should do more blog posts.

If you want to learn more about MySQL 8.0 I ask you to read my website: gabi.dev, where I posted several things on MySQL.

Happy Launch day!

Gabi’s Office Hours a.k.a. the Hallway Track

Office Hours featuring gabidavila
Book your time on gabi.tips/slots

Since travel to deliver content and awareness is being held for a while (COVID-19), I am missing the interaction I would have with people at random times during a conference, the exchange of ideas and impromptu problem solving.

The hallway track of a conference has always been my favorite part: the networking, exchanging ideas, getting feedback about products, all of that is harder to replicate without talks and social the setting of a conference.

I decided to experiment and try to find new ways to interact with “my” audience, the idea of Office Hours came, which originally is not mine, however I like the fact that I can have a technical conversation with someone that has questions about databases (not just about Cloud SQL) and also provide a window of opportunity for you to give me feedback on our products.

Examples of things we can talk about:

  • Query Performance
  • Best Practices for Migrations
  • Where to store your data
  • Should I put my Server on Kubernetes?
  • How do I migrate my data to the cloud?

The pilot started with 30 min sessions with the availability to talk to up to 10 people weekly (5h/week). However I think it is more productive a change to up to 3h/week and talking to 9 people in 20 min slots in more timezones.

Click here to book your time: gabi.tips/slots.

Tips for a good appointment:

  • Write down your questions and add it to the booking tool.
  • If a lengthy context is needed to understand your problem, please add the information in the booking tool, however do not send to me:
    • PII – Personal Identifiable Information
    • Your SQL Dump
    • Your intellectual property
    • No database credentials
  • Have defined scope of what you want to talk about, I can’t solve everything in 20 minutes.
  • Do not double book, other people should also take advantage of this

Disclaimers

This is not a guaranteed consultancy agreement, this is just people talking informally about tech problems and possible solutions, information shared and explained are guides, you are responsible for weighing your options and if any advice is executed, the outcome is your responsibility.

Your SQL IS NOT JavaScript (neither PHP)

IS NULL, IS NOT NULL, truthiness among other assertions on MySQL and PostgreSQL

People like to complain about JavaScript, how can one thing be equal to the other, i.e. null == undefined evaluates to true unless you use the triple equals ===. Other dynamic typed languages have its peculiarities, such as Ruby where 0 == true evaluates to true, the reason for Ruby is that considers 0 as a value and any value evaluates to true.

How about SQL? The answer is… it depends.

Which database are you using?

Some may be more forgiving, like MySQL doing casts for you all over the place, or more strict like PostgreSQL where you can only compare the truthiness of something of the same type.

Assertion MySQL PostgreSQL
('A' = TRUE) IS TRUE 0 invalid input syntax for type boolean: “A”
('A' IS TRUE) IS TRUE 0 invalid input syntax for type boolean: “A”
(1 = TRUE) IS TRUE 1 operator does not exist: integer = boolean
(1 IS TRUE) IS TRUE 1 argument of IS TRUE must be type boolean, not type integer
('1' IS TRUE) IS TRUE 1 1
('0' IS FALSE) IS TRUE 1 1
(1 = '1') IS TRUE 1 1
(0 = '0') IS TRUE 1 1

Beyond the implications of wrong type comparison, as you can see on lines 1 through 4 where MySQL evaluates values as true or false, you should also worry about what the fact of a column being NULL may imply when comparing two columns.

Suddenly knowing if it is true or false doesn’t matter because you cornered yourself with a third possible value: NULL. By definition NULL is not a value neither a state, it should be considered “garbage”, and no column where you know its value and type would be garbage.

In this front both databases operate the same way:

Assertion SQL
(NULL = NULL) IS TRUE 0
(NULL = NULL) IS FALSE 0
(NULL IS NULL) IS TRUE 1
(0 = NULL) IS NULL 1
(1 = NULL) IS NULL 1
('A' = NULL) IS NULL 1
(TRUE = NULL) IS NULL 1
(FALSE = NULL) IS NULL 1
(0 IS NULL) IS TRUE 0
(0 IS NOT NULL) IS TRUE 0
(0 = NULL) IS TRUE 0
(0 = NULL) IS FALSE 0
(0 = NULL) IS NOT TRUE 1
(0 = NULL) IS NOT FALSE 1
('NULL' = NULL) IS TRUE 0
('NULL' IS NULL) IS TRUE 0

The highlighted parts are usually assumptions that people expect to behave differently, for example that zero is not equal to NULL. That catches many people by surprise. It shouldn’t catch you by surprise though, because 0 is a value. The default behavior of MySQL of casting NULL to 0, on a INTEGER NOT NULL column without a DEFAULT value taught a whole generation of developers that this assumption is true. The same applies when casting a string-based column that has no default value on a NOT NULL column to empty string.

Is that a spaceship operator?

While writing this post and taking a peek into MySQL documentation, I never noticed that a NULL-safe equal operator, <=>, existed, unfortunately the MySQL website only shows the documentation from 5.5 to 8.0, so I can’t be certain if this existed in prior releases.

[code lang=sql]
SELECT
1 IS NOT NULL,
1 = NULL,
1 <=> NULL;
[/code]

Assertion MySQL
1 IS NOT NULL 1
1 = NULL NULL
1 <=> NULL 0

The case where MySQL thinks it is PHP

Another behavior I discovered when doing some JOINs were the string and integer comparison. Both databases get SELECT 1 = '1'; as true, however, MySQL takes a step further:

[code lang=sql]
SELECT 1 = '1a',
'1' * 3,
'1abc' + 4;
[/code]

Assertion MySQL PostgreSQL
1 = '1a' 1 invalid input syntax for integer: “1a”
'1' * 3 3 3
'1abc' + 4 5 invalid input syntax for integer: “1abc”

Thus behaving like PHP. PHP is expected to change this behavior soon with this RFC. PostgreSQL, in this case, is forgiving in casting a string as an integer, only if there is an integer inside of the quotes. If you mix the integer with other characters, it throws an error as you can see above.

I Know!

No, I don’t. I thought I knew enough SQL. Apparently, I was wrong.

Independent of the language you are using, you should be aware that assertions that are true in your language may not be true in SQL and the other way as well.