MySQL Shell is a pretty nice piece of software. Is not just another mysql client but it is also a tool that offers scripting capabilities for JavaScript and Python. And one of the coolest things you can do with it is to check if your MySQL 5.7 server is ready for an upgrade or not. Enter: Upgrade Checker Utility.

MySQL Shell Upgrade Checker Utility

So what is it? It is a script that will check your MySQL 5.7 instance for compatibility errors and issues with upgrading. It’s important to notice the word “check”. It doesn’t fix. Just check. Fix is on you, friendly DBA (or we can happily assist with it).

But isn’t there something that already does that? Close, but no. The mysqlchk program and the –check-upgrade parameter does something similar: Invokes the CHECK TABLE …. FOR UPGRADE command. The Upgrade …

Multiplexing Background

Historically it’s a technique used in networking to integrate multiple analog and digital signals via a shared medium. The goal of multiplexing over the network was to enable signals to be transmitted more efficiently for a given communication channel, thus achieving cost efficiency. 

Since the term Multiplexing comes from telecommunications, the industry has heavily used a device called Multiplexers – aka Mux. There was even a term called muxing where signals were often analog and digital to be combined in a single line. 

The technique was developed in the early 1870s, it’s origins to be found in telegraphy, and it has become a standard for digital telecommunications in the 20th Century. 

Following multiplexing methods are currently available: 

• Frequency Division Multiplexing (FDM)
• Time Division Multiplexing (TDM) …

MySQL 8 does not yet support the BOOLEAN type as specified in the SQL standard. There is a DDL "type" called BOOL, which is just an alias for TINYINT: create table t(b bool); select table_name, column_name, data_type, column_type from information_schema.columns where table_name = 't'; The above produces: TABLE_NAME|COLUMN_NAME|DATA_TYPE|COLUMN_TYPE| ----------|-----------|---------|-----------| t |b |tinyint |tinyint(1) | Notice … Continue reading How to Map MySQL’s TINYINT(1) to Boolean in jOOQ →

SQL CONCAT_WS Function Example | CONCAT_WS Method In SQL is today’s topic. The SQL CONCAT_WS function is used to join two or more expressions separated by a separator. It takes up to 255 input strings which are further joined by a function. If we want to perform the join operation, CONCAT requires at least 2 strings. If it is provided with only 1 string, it will raise the error.

SQL CONCAT_WS Function

If any non-character string values are passed into the function, it will be implicitly converted to the strings before concatenating.

If NULL is added to the function, it converts it into the empty string with VARCHAR (1).

See the following syntax.

SELECT CONCAT_WS (separator, expression1, expression2, expression3…)

Parameters Separator

We just wrapped up what was a very exciting OOW 2019 - San Francisco for MySQL.  Our MySQL track included 29 sessions, a keynote with 2 customer testimonials (Mercari and WePay), 1 tutorial, 1 Hands-on lab, 1 Birds of a Feather, and our always fun and enjoyable MySQL Community Reception.  

A BIG Thank You to the companies who came to share their experience and testimonial about how MySQL helps scale their company such as Facebook, JP Morgan Chase WePay, Credorax, Mercari, Zuora, and more.

Our focus this year: SECURITY.  With 3,800 breaches and over 4 Billion Records Stolen in just H1 2019, securing data has become a priority for any business. The first part of the keynote covers the new security features from Oracle and MySQL implemented in our latest version of the Enterprise Edition.

Other highlights for MySQL:

• MySQL 8.0,  fastest adoption of any version with over 26% …

In a previous post, I showed you how to compile Percona Mysql 5.7 on Raspberry PI 3. Now, I’ll show you how to compile and run the latest version of Percona XtraDB Cluster 5.7.26.

We will need at least 3 RaspberryPi 3 boards, and I recommend you use an external SSD drive to compile and use as MySQL’s “datadir” to avoid the stalls associated with the microSD card, which will cause PXC to run slow.

In this post, we are going to run many OS commands and configure PXC. I recommend having minimal knowledge about PXC and Linux commands.

How to install CentOS

Download the centos image from this link …

Overview The Skinny

In this blog post we explore various options for performance tuning MySQL server for better slave replication performance.

A Tungsten Cluster relies upon the Tungsten Replicator to move events from the master node to the slaves. Once the event has been transferred to the slave as THL on disk, the slave applier will then attempt to write it to the database. The Replicator can only apply events as fast as MySQL allows. If the MySQL server is somehow slow or blocking, then the Replicator will be as well.

A properly-tuned database server in addition to infrastructure and SysAdmin best practices will go quite a long way towards high-performance slave apply.

The Question Recently, a customer asked us:

During one of our load tests, we had a peak of 60k writes/min, averaging …

Reserved Words and UTF8MB4 Issues The upgrade checker utility in the new MySQL Sell will warn you about potential problems.  The two most common problems I have seen are finding out one of your column names is a reserved word and character sets.
Reserved Words
You will spot reserved word issues on the second step of the upgrade check: 2) Usage of db objects with names conflicting with reserved keywords in 8.0   Warning: The following objects have names that conflict with reserved     keywords that are new to 8.0. Ensure queries sent by your applications use     `quotes` when referring to them or they will result in errors.   More information:     https://dev.mysql.com/doc/refman/en/keywords.html
  davetest.reserved_word.over - Column name
In the above we are being told that in the schema 'davetest' in the table 'reserved_word' that there is a column named 'over' that …

My first talk is a tutorial Testing like a boss: Deploy and Test Complex Topologies With a Single Command, scheduled at Percona Live Europe in Amsterdam on September 30th at 13:30.

My second talk is Amazing sandboxes with dbdeployer scheduled on October 1st at 11:00. It is the same topic as the tutorial, but covers a narrow set of features, all in the *amazing* category.

The tutorial introduces a challenging topic, because when people hear testing, they imagine a troop of monkeys fiddling with a keyboard and a mouse, endlessly repeating a boring task. What I want to show is that testing is a creative activity and, with the right tools and mindset, it could be exciting and rewarding. During my work as a quality assurance engineer, I have always seen a boring task as an opportunity to automate. …

This tutorial explains how to create a user with a password in MySQL. We’ll use the MySQL Create User command and describe it with the help of examples. MySQL Create User with Password This command creates a new MySQL user and grants privileges. Usually, you might be using the root user to access a database. […]

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