In this post we describe MySQL connections, user threads, and scaling. We hope that an increased understanding of how MySQL works will help application developers and system administrators to make good choices and trade-offs. We describe how connections work in a plain community server and we do not cover related topics such as thread pooling, resource groups, or connection multiplexing in this post.…
Category Archives: MySQL
Improvements to ROLLUP in MySQL
ROLLUP has been supported in MySQL for sometime now. But until now its use has come with two implementation restrictions: it cannot be combined with DISTINCT or ORDER BY in the same query expression. Starting in 8.0.12, these limitations have been lifted.…
MySQL User Camp, Bangalore – February 13th, 2019
At MySQL we love opportunities to interact with our users and MySQL User Camp gives us the chance to do just that. The first MySQL User Camp of this year was held on February 13th 2019 at the Oracle Kalyani Magnum Office.…
MySQL 8.0: New Storage Format for Compressed BLOBs
In this article, let us look at the new storage format of compressed large objects (compressed LOB or ZLOB). In my previous article MySQL 8.0: InnoDB Introduces LOB Index For Faster Updates, I have explained about the new storage format of uncompressed LOBs. …
JSON specific window functions in MySQL 8.0
In 8.0, we introduced window functions in the MySQL server. A detailed explanation of how window functions can be used and what is supported in 8.0 is explained here.
Now, let’s see what is new in window functions in the latest version 8.0.…
Bootstrapping the transactional data dictionary
In a previous blog post, we discussed how the initialization and restart of the MySQL server has changed between versions 5.6, 5.7 and 8.0. Now, we will take a closer look at MySQL 8.0 to explain in more detail how the transactional data dictionary is bootstrapped.…
Importing Data from MongoDB to MySQL: BSON Data Types
The latest release of the MySQL Shell 8.0.14 (GA) improved the JSON import utility to support the conversion of more BSON data types from the strict mode representation of MongoDB Extended JSON. This removes a previous limitation regarding the import of more complex MongoDB data types to MySQL, making it more reliable.…
What is LOAD DATA and how does it work
I would like to highlight a less known MySQL SQL command, analyze how it works and understand some of the decisions that need to be made when using it.
Let’s start with the basics: The Reference Manual.
It does have a lot to say about LOAD DATA.…
Support for LATERAL derived tables added to MySQL 8.0.14
In the just-released MySQL 8.0.14 I added a feature called LATERAL derived tables.
The manual describes the syntax and has examples of how the feature can be used to find greatest values in tables. In the present post I’m going to consider a different problem solved by LATERAL: let’s say that we have a bunch of nodes, and want to make a “random graph”, by connecting every node to other nodes.…
The complete list of new features in MySQL 8.0
There are over 250 new features in MySQL 8.0. The MySQL Manual is very good, but verbose. This is a list of new features in short bullet form. We have tried very hard to make sure each feature is only mentioned once.…