The latest from the MySQL community

At Shopify, we run a large fleet of MySQL servers, with numerous replica-sets (internally known as “shards”) spread across three Google Cloud Platform (GCP) regions. Given the petabyte scale size and criticality of data, we need a robust and efficient backup and restore solution. We drastically reduced our Recovery Time Objective (RTO) to under 30 minutes by redesigning our tooling to use disk-based snapshots, and we want to share how it was done.

Challenges with Existing Tools

For several years, we backed up our MySQL data using Percona’s Xtrabackup utility, stored its output in files, and archived them on Google Cloud Storage (GCS). While pretty robust, it provided a significant challenge when backing up and restoring data. The …

Percona is happy to announce the first experimental binary of Percona XtraDB Cluster 8.0 on October 1, 2019. This is a major step for tuning Percona XtraDB Cluster to be more cloud- and user-friendly. This release combines the updated and feature-rich Galera 4, with substantial improvements made by our development team.

Improvements and New Features

Galera 4, included in Percona XtraDB Cluster 8.0, has many new features. Here is a list of the most essential improvements:

• Streaming replication supports large transactions
• The synchronization functions allow action coordination (wsrep_last_seen_gtid, wsrep_last_written_gtid, wsrep_sync_wait_upto_gtid)
• More granular and improved error logging. wsrep_debug is now a multi-valued variable to assist in controlling the logging, and logging messages have been significantly improved.
…

Lower() Function Example In MySQL and SQL Server is today’s topic. The SQL LOWER function converts all the characters in a string into lowercase. If you want to convert all characters in a string into uppercase, you should use the UPPER function. SQL LOWER function is used for lowering the case of a string, i.e. all the characters in the specified string will be converted to lower case. This is one of the String functions.

SQL LOWER Function

See the following syntax.

SELECT LOWER (input_string)

PARAMETERS:

Input_string: It is the string whose characters are to be converted to lowercase. The input string can be any string or any table column.

NOTE:

If any number …

MySQL Galera Cluster 4.0 is the new kid on the database block with very interesting new features. Currently it is available only as a part of MariaDB 10.4 but in the future it will work as well with MySQL 5.6, 5.7 and 8.0. In this blog post we would like to go over some of the new features that came along with Galera Cluster 4.0.

Galera Cluster Streaming Replication

The most important new feature in this release is streaming replication. So far the certification process for the Galera …

SQL Left Function Example | LEFT() In SQL Server And MySQL is today’s topic. LEFT FUNCTION in SQL is used for extracting a substring starting from the left, followed by the number of characters. The LEFT() function extracts several characters from the string (starting from left).

SQL Left Function

The LEFT() function extracts a given number of characters from the left side of a supplied string.

The syntax of the LEFT() function is as follows.

SELECT LEFT (string, no_of_characters);

See the following parameters.

PARAMETERS:

1. String: An input string from which the substring will be extracted and can be a literal string, variable or a column.
2. No_of_characters: Number of characters you wish to extract from the string.

The LEFT() function returns a value of VARCHAR when …

Overview

Clustering provides high availability and disaster recovery, along with the ability to read-scale both locally and globally. Some clusters even provide active/active capabilities, which others have a single master.

Real time database replication is a must for clustering and other key business purposes, like reporting. There are a number of replication technologies available for MySQL, and some are even bundled into various solutions. When choosing a replication methodology, it is paramount to understand just how the data moves from source to target. In this blog post, we will examine how asynchronous, synchronous, and “semi-synchronous” replication behave when used for clustering. Also, we will explore how …

MySQL has had an interesting optimization for years now1, which has popped up from time to time: in certain circumstances, it may choose to use an index that is index-wise less efficient, but provides the resulting rows in order, to avoid a filesort of the result.

What does this typically look like in production? A query that seems simple and easy takes much longer than it should, sometimes. (Perhaps in production, the query gets killed by pt-kill or exceeds the max_execution_time provided.) The query could be very simple indeed:

SELECT ... WHERE `other_id` = 555 ORDER BY `id` ASC LIMIT 1

There’s an index on other_id, and running the query with an appropriate USE INDEX, the query is fast. Even weirder, changing the query to use LIMIT 10 causes it to …

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

  • For detailed information see the blog post from last week.
• OpenTech Summit, Bangkok, …

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 …

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 …