The goal of this blog post is to explain the various types of transaction isolation levels available in MySQL. After reading the blog, you will be able to explain dirty reads, non-repeatable reads, and the concept of phantom rows as well.

What is the Isolation Level in MySQL?

Isolation (I) is one of the properties from ACID. It defines how each transaction is isolated from other transactions and is a critical component of application design. As per the SQL:1992 standard, InnoDB has four types of Isolation levels. Below, I have listed the types in order, and each transaction isolation level provides better consistency compared to the previous one.

• READ-UNCOMMITTED
• READ-COMMITTED
• REPEATABLE-READ – ( MySQL’s DEFAULT )
• SERIALIZABLE

You can change the isolation level using the variable “transaction_isolation” at runtime. As transaction isolation changes can …

In this  blog series, I’m describing how InnoDB locks data (tables and rows) in order to provide illusion to clients that their queries are executed one after another, and how this was improved in recent releases.
In InnoDB Data Locking – Part 1 “Introduction” I’ve introduced basic concepts required to understand current post:

• databases, tables, rows (like files on a shared drive, spreadsheets inside a file, and rows inside a spreadsheet)
• serializability of transactions (ability to explain states observed over time with a convincing story about relative order of parallel operations)
• timeouts (for misbehaving lock owners, and to resolve deadlocks)
• reader-writer lock …

While it's easier to measure the impact of Dynimize if you are running a MySQL benchmark with clear metrics, it can sometimes be a challenge on a production workload where you don't have precise performance analytics or metrics available. There are many great MySQL performance analysis tools out there, however they can often take time and effort to setup.

The simple measureDyniMysql script was created for this exact reason, and does not incur any MySQL downtime. You can find it at /opt/dynimize/measureDyniMysql after installing Dynimize. It will report the change in MySQL queries per second and mysqld CPU usage after applying Dynimize. Here is how to use it.

1. Install and start dynimize, and get your mysqld process into the dynimized state. For example, the …

MySQL is the number one open source relational database management system in the world, and is used by millions of developers across all application types. DigitalOcean, a fast-growing cloud provider that’s increasing in popularity amongst the developer community, is a great host to consider for your MySQL deployments. In this article, we’re going to show […]

 FOSDEM has become one of the biggest shows on the calendar of the MySQL Community Team.  FOSDEM itself, until this year, is barely contained chaos at a university in Brussels with no pre-enrollment for any of the dozens of themed rooms and no head count.  This year the event is virtual so you do not have to get to Belgium.

The MySQL and Friends Developer Room is Sunday and starts at 10:00am  Belgium time with a retrospective of the first twenty five years of MySQL. This is followed 15 other talks of about 25 minutes on everything from ARM to user management. 

Join Brian Walters and Brandon Fleisher for an interactive discussion around new service and software offerings coming from Percona.

Oracle has decided that MySQL 5.6 will reach its end of life in February 2021. This means there will be no more updates and, more importantly, no more security fixes for discovered vulnerabilities. Yikes! Did you know you have options? Did you know Percona can solve this problem? Tune in to find out how.

Choosing a database-as-a-service (DBaaS) provider can be a daunting challenge. Not ready to move to DBaaS in the public cloud? Or, are you constrained to on-prem deployment due to regulations or other market conditions? Tune-in to learn how Percona is bringing the benefits of simplified DBaaS deployment to the on-prem, private cloud, and hybrid datacenter.

This interactive webinar will be conducted in a roundtable forum style. Bring your interests, bring …

We are happy to announce another MySQL Webinar on the topic of "", see details below:

• Date: Feb 16, 2021
• Time: 2:00 pm Dubai time (GMT+4)
• Topic: Best practices for MySQL Performance
• Description: Of all the features that are available in MySQL, we will still need to optimize and fine tune our environment to our specific needs and the immediate or not-too-distant future growth. In this session we will have a look into ways to analyze the instances' performance and take into consideration some suggestions and best practices.
• Speaker: Carsten Thalheimer, the MySQL Master Principal Sales Consultant
• Registration …

We are happy to announce another MySQL Webinar on the topic of "", see details below: Date: Feb 16, 2021 Time: 2:00 pm Dubai time (GMT+4) Topic: Best practices for MySQL Performance Description: Of all the features that are available in MySQL, we will still need to optimize and fine tune our environ...

Why do Continuent customers say year after year that Tungsten Clustering is a better MySQL HA/DR/Geo-Scale clustering and replication technology - in the cloud, on-prem, hybrid-cloud, multi-cloud - compared to alternatives such as Amazon Aurora for MySQL, Galera Cluster and host of others? We have put together a comprehensive comparison so you can learn about the pros and cons of various MySQL solutions for business-critical and mission-critical apps - and make an informed decision about what’s best for your needs and environment!

Tags: MySQLmysql clusterHigh AvailabilityDisaster Recovery

Hi and thanks to all who attended my webinar on Tuesday, January 26th titled Using PMM to Identify & Troubleshoot Problematic MySQL Queries!

Like we do after all our webinars, we compile the list of questions that were answered verbally and also those that were posed yet remained unanswered since we ran out of time during the broadcast.  Before we get to the questions, I wanted to make sure to include a link to the RED Method for MySQL Queries by Peter Zaitsev, Percona’s CEO:

https://grafana.com/grafana/dashboards/12470

Hi Michael, you suggested that table create and update times should be ignored. Surely these values come from information_schema.tables? Does that not reflect what I would see if I …