Series Introduction

Back in 2016 I decided to write a blog series on InnoDB in hopes that it would help give a good description of the high level mechanics of the storage engine. The main motivating factor at that time was that I knew there was a lot of information out there about InnoDB, but a lot of it was ambiguous or even contradictory and I wanted to help make things a bit clearer if I could.

Now there’s a new storage engine that’s rising in popularity that I feel needs similar attention. Specifically MyRocks, the log-structured merge-driven RocksDB engine in MySQL. Given the amount of discussion in the community about MyRocks, I’m sure most of you already have some degree of familiarity, or at the very least have heard the name.

Now we’ve arrived at a point where this is no longer just a Facebook integration project and major players in the community like Maria and Percona have their own implemented …

Python 2 reaches EOL on 2020-01-01 and one of its commonly used third-party packages is MySQL-python. If you have not yet migrated away from both of these, since MySQL-python does not support Python 3, then you may have come across some issues if you are using more recent versions of MySQL and are enforcing a secured installation. This post will look at two specific issues that you may come across (caching_sha2_password in MySQL 8.0 and TLSv1.2 with MySQL >=5.7.10 when using OpenSSL) that will prevent you from connecting to a MySQL database and buy …

Introduction In this article, we are going to see how we can implement a database job queue using SKIP LOCKED. I decided to write this article while answering this Stack Overflow question asked by Rafael Winterhalter. Since SKIP LOCKED is a lesser-known SQL feature, it’s a good opportunity to show you how to use it and why you should employ it, especially when implementing a job queue task. Domain Model Let’s assume we have the following Post entity which has a status Enum property looking as follows: The PostStatus Enum encapsulates the... Read More

The post How to implement a database job queue using SKIP LOCKED appeared first on Vlad Mihalcea.

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MySQL stores several files on disk. Even in MySQL 8 where the data dictionary is stored in InnoDB tables, there are still all the tablespace files. Different file system behave differently, and one particular challenge is case sensitivity. On Microsoft Windows, the case does not matter, on Linux the case is important, and on macOS the case of the file names is preserved but the operating system by default makes it look like it is case insensitive.

Which convention that is the correct depends on your personal preference and use case. Between case sensitivity and case insensitivity, it basically boils down to whether mydb, MyDB, and MYDB should be the same identifier or three different ones. Since …

SQL Where Clause Example | SQL Where Query Tutorial is today’s topic. The WHERE clause is used to filter the database records. The WHERE clause is used to extract only those records that fulfill the specified condition. The SQL WHERE clause is used to specify the condition while fetching the data from a single table or by joining the multiple tables. If a given condition is satisfied, then only it returns the specific value from the table. You should use a WHERE clause to filter the records and fetching the necessary records.

SQL Where Clause Example

The WHERE clause is not only used in the SELECT statement; it is also used in an UPDATE, DELETE statement. The syntax of a SELECT statement with a WHERE clause is following.

SELECT column1, column2, columnN 
FROM table_name
WHERE [condition]

“SELECT column1, column2, column3 FROM tableName” is the standard …

In my previous post, some time ago, I wrote about the new cluster feature of ProxySQL. For that post, we were working with three nodes, now we’ll work with even more! If you’ve installed one ProxySQL per application instance and would like to work up to more, then this post is for you. If this is new to you, though, read my earlier post first for more context.

Check the image below to understand the structure of “one ProxySQL per application”. This means you have ProxySQL installed, and your application (Java, PHP, Apache server etc) in the same VM (virtual machine).

Having taken a look at that you probably have a few questions, such as:

• What happens if you have 20 nodes …

Throughout this tutorial, we'll be using PHP with React and Axios to create a simple REST API application with CRUD operations. In the backend we'll use PHP with a MySQL database.

The PHP backend will expose a set of RESTful API endpoints so we'll be using the Axios library for making Ajax calls from the React.js UI.

We'll also see how to handle forms in React and how to send multipart form data with Axios using FormData.

In this tutorial, we are going to integrate React with PHP using Babel in the browser and a <script> tag. As such, we'll serve the React application from PHP so we don't need to enable CORS in our server since both the backend and frontend are served from the same domain.

We'll see the other approach of using two separate servers for the frontend and backend apps in another tutorial which will use the create-react-app to create the React project.

Prerequisites

You must …

MySQL InnoDB Cluster was introduced in MySQL version 5.7 and consists of three parts – Group Replication, MySQL Shell and MySQL Router. MySQL InnoDB Cluster provides a complete high availability solution for MySQL. In this post, I am going to explain how to setup a three-node cluster using the MySQL Shell.

PDO stands for PHP Data Object and it's an extension that provides an interface for communicating with many supported popular database systems such as MySQL and Oracle, PostgreSQL and SQLite, etc.

It's provided starting with PHP 5.1.

Since PDO abstracts away all the differences between various database management systems, you only need to change the information about your database in your code in order to change the database system used in your PHP application.

Setting up PDO

PDO is added by default starting with PHP 5.1 but you need to set the necessary database driver in the php.ini file: extension=pdo.so extension=pdo_mysql.so

Creating a MySQL Database

Let's start by creating a MySQL using the mysql client. In your terminal, run the following command: $ mysql -u root -p

Enter your MySQL database password when prompted.

Next, run the following SQL instruction to create a …

We have covered session management in ExpressJs using global variable technique which of course will not work in case of shared server or concurrent execution of http requests which is most familiar production scenario.

Codeforgeek readers requested to provide solution for these issue and the optimal one is to use external session storage which is not dependent on application requests, answer is Redis cause this is the light weight and easy to use NoSQL database.

In this tutorial i am going to explain how to design and code session oriented express web applications by using Redis as external session storage.

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To get familiar with Session handling in ExpressJS I recommend to read our first article …