As follow up to the previous blog announcement we would like to inform you about where you can find MySQL & MySQL Community Team during October & November 2019. Please find the list below:
October 2019:
PerconaLive, Amsterdam, Holland, September 30-October 2, 2019
EverData a leading data center and cloud solution provider in India has recently been writing quite a bit about Galera Cluster and it seems like we should highlight them. For one, they’ve talked about streaming replication in Galera Cluster 4, available in MariaDB Server 10.4. However, let us focus on their post: Galera Cluster vs Amazon RDS: A Comprehensive Review.
They compared MySQL with MHA, MySQL with Galera Cluster and also Amazon Web Services (AWS) Relational Database Service (RDS). Their evaluation criteria was to see how quickly there would be recovery after a crash, as well as performance while managing concurrent reads and writes.
In their tests, they found that time for …
[Read more]As soon as you start running a database server and your usage grows, you are exposed to many types of technical problems, performance degradation, and database malfunctions. Each of these could lead to much bigger problems, such as catastrophic failure or data loss. It’s like a chain reaction, where one thing can lead to another, causing more and more issues. Proactive countermeasures must be performed in order for you to have a stable environment as long as possible.
In this blog post, we are going to look at a bunch of cool features offered by ClusterControl that can greatly help us troubleshoot and fix our MySQL database issues when they happen.
Database Alarms and Notifications
For all undesired events, ClusterControl will log everything under …
[Read more]Author: Robert Agar
One of the tasks that a database team needs to be prepared to perform is a MySQL migration. In the deep, dark past of the early 21st Century, this would have involved moving a MySQL database from one server to another one located within your company’s data center. This might have been done to take advantage of better hardware with which to provide optimal service to the database’s end users. As the IT needs of a business change, systems are often shuffled around to make the best use of computing resources.
Besides enjoying the faster performance the main impact of migration on your database team is the requirement to use a different IP address to connect to the server hosting the databases they support. No big deal. The assumption would be that all tools and monitoring platforms in place before the migration will continue to function correctly. Once the dust settles, all is well in …
[Read more]In MySQL and Oracle, you set a session variable quite differently. That means you should expect there differences between setting a session variable in Postgres. This blog post lets you see how to set them in all three databases. I’m always curious what people think but I’m willing to bet that MySQL is the simplest approach. Postgres is a bit more complex because you must use a function call, but Oracle is the most complex.
The difference between MySQL and Postgres is an “@”
symbol versus a current_setting() function call.
Oracle is more complex because it involves the mechanics in
Oracle’s sqlplus shell, SQL dialect, and PL/SQL
language (required to assign a value to a variable).
MySQL
MySQL lets you declare a session variable in one step and use it one way in a SQL statement or stored procedure.
When building network libraries for Node.js, as we do at work, one quite quickly comes by Node's Buffer type. A Buffer gives access to a memory region in a quite raw form, allowing to handle raw data and allowing to interpret binary streams. The Buffer interface predates ES6 TypedArrays and has some optimizations.
Two optimisations are notable:
For one the slice() method does not copy data, but returns a view on the underlying data. This makes it quite efficient to work on a window of the data, but when writing one has to be careful. Simple example:
const buffer = Buffer.from("hello"); …[Read more]
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 …
[Read more]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:
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
…[Read more]