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MySQL 8.0.13 was released this week. There are several exciting changes including functional indexes and using general expressions as the default value for your columns. So, I will recommend you to get MySQL 8.0.13 installed and try out the new features. You can read about changed in the release notes section of the MySQL documentation and in Geir’s release blog.

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The short version

I created > one billion InnoDB tables in MySQL 8.0 (tables, not rows) just for fun. Here is the proof:

$ mysql -A
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1425329
Server version: 8.0.12 MySQL Community Server - GPL
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select count(*) from information_schema.tables;
+------------+
| count(*)   |
+------------+
| 1011570298 |
+------------+
1 row in set (6 hours 57 min 6.31 sec)

Yes, it took 6 hours and 57 minutes to count them all!

Why does anyone need one billion tables?

In my previous blog post, I created and tested  …

So, if we’re applying GDPR to our system, and we’re already making use of MySQL Transparent Data Encryption / keyring, then here’s an example on how to migrate from filed-based keyring to the encrypted keyring. Online.

If you’re looking to go deeper into the TDE then I suggest reading the MySQL Server Team’s InnoDB Transparent Tablespace Encryption blog.

You’d already have your environment running, whereas I have to create one.. give me a minute please, 8.0.12 here we come:

mysqld --defaults-file=my_okv.cnf --initialize-insecure --user=khollman
mysqld --defaults-file=my_okv.cnf --user=khollman &

mysql …

Probably not well known but quite an important optimization was introduced in MySQL 5.6 – reduced overhead for “read only transactions”. While usually by a “transaction” we mean a query or a group of queries that change data, with transaction engines like InnoDB, every data read or write operation is a transaction.

Now, as a non-locking read operation obviously has less impact on the data, it does not need all the instrumenting overhead a write transaction has. The main thing that can be avoided, as described by documentation, is the transaction ID. So, since MySQL 5.6, a read only transaction does not have a transaction ID. Moreover, such a transaction is not visible in the SHOW ENGINE INNODB STATUS output, though I will not go deeper on what really that means under the hood in this article. The fact is that this optimization …

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Since MySQL 5.6, the digest feature of the MySQL Performance Schema has provided a convenient and effective way to obtain statistics of queries based on their normalized form. The feature works so well that it has almost completely (from my experience) replaced the connector extensions and proxy for collecting query statistics for the Query Analyzer (Quan) in MySQL Enterprise Monitor (MEM).

MySQL 8 adds further improvements to the digest feature in the Performance Schema including a sample query with statistics for each digest, percentile information, and a histogram summary. This blog will explore these new features.

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The second alpha build of Percona XtraBackup 8.0.2 is now available in the Percona experimental software repositories.

Note that, due to the new MySQL redo log and data dictionary formats, the Percona XtraBackup 8.0.x versions will only be compatible with MySQL 8.0.x and Percona Server for MySQL 8.0.x. This release supports backing up Percona Server 8.0 Alpha.

For experimental migrations from earlier database server versions, you will need to backup and restore and using XtraBackup 2.4 and then use mysql_upgrade from MySQL 8.0.x

PXB 8.0.2 alpha is available for the following …

The release of MySQL 8.0 has brought a lot of bold implementations that touched on things that have been avoided before, such as added support for common table expressions and window functions. Another example is the change in how AUTO_INCREMENT (autoinc) sequences are persisted, and thus replicated.

This new implementation carries the fix for bug #73563 (Replace result in auto_increment value less or equal than max value in row-based), which we’ve only found about recently. The surprising part is that the use case we were analyzing is a somewhat common one; this must be affecting a good number of people out there.

Understanding the bug

The business logic of the use case is such the UNIQUE column found in a table whose id is managed by an AUTO_INCREMENT sequence needs to be updated, and this is done with a …

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The traditional way to monitor replication in MySQL is the SHOW SLAVE STATUS command. However as it will be shown, it has its limitations and in MySQL 5.7 and 8.0 the MySQL developers have started to implement the information as Performance Schema tables. This has several advantages including better monitoring of the replication delay in MySQL 8.0. This blog discusses why SHOW SLAVE STATUS should be replaced with the Performance Schema tables.

The Setup

The replication setup that will be used for the examples in this blog can be seen in the following figure.

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There are multiple way to setup replication with MySQL 8.0 and our replication offer as never been so rich: asynchronous, semi-synchronous, group replication, multi-source, … and much more options !

But if you want to setup a very quick Master-Slave environment from scratch for a quick test (you can always use dbdeployer), here are some commands to make it right the first time

Requirements

You need to have MySQL 8.0 installed and running on both servers and with the same initial data (a fresh install for example). Here we use mysql1 and mysql2. We will also use GTID as it’s much more convenient.

Servers Configuration

Let’s setup mysql1 first:

mysql1> SET PERSIST server_id=1; 
mysql1> SET …

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There are various ways to shutdown MySQL. The traditional cross platform method is to use the shutdown command in the mysqladmin client. One drawback is that it requires shell access; another is that it cannot start MySQL again automatically. There are platform specific options that can perform a restart such as using systemctl on Linux or install MySQL as a service on Microsoft Windows. What I will look at here though is the built in support for stopping and restarting MySQL using SQL statements.

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