A common MySQL strategy to perform updates with accumulating functions is to employ user-defined variables, using the UPDATE [...] SET mycol = (@myvar := EXPRESSION(@myvar, mycol)) pattern.

This pattern though doesn’t play well with the optimizer (leading to non-deterministic behavior), so it has been deprecated. This left a sort of void, since the (relatively) sophisticated logic is now harder to reproduce, at least with the same simplicity.

In this article, I’ll have a look at two ways to apply such logic: using, canonically, window functions, and, a bit more creatively, using recursive CTEs.

• Requirements and background
• …

Backup of Database is the pillar of our system which is necessary and mandatory to provide us data incase of crash, new machine provisioning and many other scenarios listed here. 
As part of the backup process, a snapshot is taken, and the data is transferred to the Recovery Services vault with no impact on production workloads. The snapshot provides different levels of consistency, as described below:1. Application-consistent: App-consistent backups capture memory content and pending I/O operations. App-consistent snapshots use a VSS writer (or pre/post scripts for Linux) to ensure the consistency of the app data before a backup occurs.When you're recovering a VM with an app-consistent snapshot, the VM boots up. There's no data corruption or loss. The apps start in a consistent state.2. File-system consistent: File-system consistent backups provide consistency …

Recently we have setup Orchestrator in High Availability mode using RAFT. We are running a 3 node setup in which there used to be a leader and rest 2 are Healthy raft member.

So To access orchestrator service we may only speak to the leader node using /api/leader-check as HTTP health check for our proxy. This url returns http 200 on leader …

First I want to thank everyone who attended my May 21, 2020 webinar “How Safe is Asynchronous Master-Master Setup in MySQL?“. Recording and slides are available on the webinar page.

Here are answers to the questions from participants which I was not able to provide during the webinar.

Q: What do you generally think of hosting Relational Databases on VM’s as opposed to Bare metals?

A: With modern hardware and modern virtual machines this is absolutely possible. I know about many successful high loaded applications that run MySQL on VMs.

Just note that running a few VMs on a single physical machine may lead to resource loss rather than saving. For …

We are proud to announce that Percona was selected as a participating organization for the Google Summer of Code (GSoC) 2020 program, this is our second year as a participating org with the GSoC program.

GSoC is a great program to involve young student developers in open source projects. We participated in the program in 2019 for the first time and we were really happy and satisfied with the results.
Percona Platform Engineering team decided to participate again for the 2020 program and we are glad and really happy to inform you that we were selected and welcome the student to work with our team during the summer of 2020 on their GSoC Project.

Preparations

We started planning for GSoC around November-December 2019, with the help from our Product Management team, we were able to shortlist a few ideas which we thought were really the right fit for …

I agree with Justin Swanhart. InnoDB is not losing atomicity, when LOCK WAIT TIMEOUT rollback or commit depends on the application. application should handler the exception

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Constraint Checks that actually checked the constraints were introduced last year with MySQL 8.0.16 and they really do help you keep bad data out of your database.  I have found them very handy in the past year but today I spotted a question on a website about how to remove a Constraint Check.

What is a Constraint Check?It is an integrity check.  In the following example a constraint is set up to make sure the calues of the column 'is' are greater than one hundred.


CREATE TABLE c1 (id INT NOT NULL, 
   CONSTRAINT id_gt_100 CHECK (('id' > 100))
);

A simple test with a value in range runs perfectly fine.

INSERT INTO c1 (id) VALUES (10000);
Query OK, 1 row affected (0.0037 sec)

But you will receive an error if the value of 'is' is less than  100.

INSERT INTO c1 (id) …

In systems nowadays, improving security is a must! One of the weakest links in the security system is the user password from where an attacker can enter. In order to improve password strength and security, MySQL provides a plugin called “Validation plugin” which can be configured to enforce a set of rules for passwords.

Installation

The plugin can be enabled by executing the following at runtime:

INSTALL PLUGIN validate_password SONAME 'validate_password.so';

Or by adding the plugin in the configuration file, but this requires bouncing MySQL for it to take effect:

[mysqld]
plugin-load-add=validate_password.so

It’s also suggested to add the following variable in my.cnf so that the plugin cannot be removed at runtime (also requires a MySQL bounce to take effect):

[mysqld]
validate-password=FORCE_PLUS_PERMANENT

Checking Installation

Percona engineers often need to analyze and review complex SQL database queries. Good formatting can make these SQL queries much easier to understand and work with. Without clear formatting, queries can become confusing and hard to debug.

Online query formatting services provide one set of solutions. Examples are Code Beautify, FreeFormatter, and sqlformat.org. However, many users are not comfortable sharing their queries with third-party services, especially if your SQL code contains confidential information.

This article examines alternatives to online tools for SQL query formatting tools that have been successfully used by Percona engineers. These solutions come in different types:

1. Plug-ins to your code editor or …

This session at Percona Live ONLINE was presented by Akshay Suryawanshi, Senior Production Engineer at Shopify, and Jeremy Cole, Senior Staff Production Engineer – Datastores at Shopify.

Shopify is an online and on-premise commerce platform, founded in 2006. Shopify is used by more than a million merchants, and hundreds of billions of dollars of sales have happened on the platform since its inception. The company is a large user of MySQL, and the Black Friday and Cyber Monday weekends are their peak dates during the year, handling hundreds of billions of queries with MySQL. This year’s presentation was an opportunity to talk about the company’s challenges and progress over the last twelve months.

Key Google Cloud concepts from the presentation

As part of the presentation, it’s important to understand the naming conventions that exist around …