I personally believe that the best way to deliver a complicated message to an audience, is by using a simple example. So in this post, I chose to demonstrate how to obtain insights from MySQL's EXPLAIN output, by using a simple SQL query which fetches data from StackOverflow's publicly available dataset.

The EXPLAIN command provides information about how MySQL executes queries. EXPLAIN can work with SELECT, DELETE, INSERT, REPLACE, and UPDATE statements.

We'll first analyze the original query, then attempt to optimize the query and look into the optimized query's execution plan to see what changed and why.

This is the first article in a series of posts. Each post will walk you through a more advanced SQL query than the previous post, while demonstrating more insights which can be obtained from MySQL's execution plans.

The query and database …

MySQL supports replicating to a slave that is one release higher. This allows us to easily upgrade our MySQL setup to a new version, by promoting the slave and pointing the application to it. However, though unsupported, there are times when the MySQL version of slave deployed is one release lower. In this scenario, if your application has been performing much better on an older version of MySQL, you would like to have a convenient option to downgrade. You can simply promote the slave to get the old performance back.

The MySQL manual says that ROW based replication can be used to replicate to a lower version, provided that no DDLs replicated are incompatible with the slave. One such incompatible command is ALTER USER which is a new feature in MySQL 5.7 and not available on 5.6. :

ALTER USER …

In Jesper’s blog on Persisted Variables …he introduced us to this new capability using the PERSIST and PERSIST_ONLY keywords.  With new MySQL features, such as PERSIST come new areas that we need to pay attention to when doing backup and restore activities.  Namely to manage the log file that the PERSIST capability uses, as it’s a… Read More »

Join Percona Chief Evangelist Colin Charles as he covers happenings, gives pointers and provides musings on the open source database community.

I consider this to be the biggest news for the week: Alpha Build of Percona Server for MySQL 8.0. Experiment with it in a Docker container. It is missing column compression with dictionary support, native partitioning for TokuDB and MyRocks (excited to see that this is coming!), and encryption key rotation and scrubbing. All in, this should be a fun release to try, test, and also to file bugs for!

Database paradigms are changing, and it is interesting to see Cloudflare introducing Workers KV a key-value store, that is eventually consistent and highly distributed (at their global …

Starting with PMM 1.13,  PMM uses Prometheus 2 for metrics storage, which tends to be heaviest resource consumer of CPU and RAM.  With Prometheus 2 Performance Improvements, PMM can scale to more than 1000 monitored nodes per instance in default configuration. In this blog post we will look into PMM scaling and capacity planning—how to estimate the resources required, and what drives resource consumption.

We have now tested PMM with up to 1000 nodes, using a virtualized system with 128GB of memory, 24 virtual cores, and SSD storage. We found PMM scales pretty linearly with the available memory and CPU cores, and we believe that a higher number of nodes could be …

Alpha Build of Percona Server 8.0 released

An alpha version of Percona Server 8.0 is now available in the Percona experimental software repositories. This is a 64-bit release only. 

You may experiment with this alpha release by running it in a Docker container:

$ docker run -d -e MYSQL_ROOT_PASSWORD=password -p 3306:3306 perconalab/percona-server:8.0.12.alpha

When the container starts, connect to it as follows:

$ docker exec -ti $(docker ps | grep -F percona-server:8.0.12.alpha | awk '{print $1}') mysql -uroot -ppassword

Note that this release is not ready for use in any production environment.

Percona Server 8.0 alpha is available for the following …

In a previous blog, I discussed how to pull, install and run MySQL 8.0 with Docker.  I showed how to connect to the Docker daemon with MySQL.

Now I will show you how to connect to the same Docker instance using the MySQL Shell which is a tool to use Document Store and to create InnoDB Clusters.

Installing Docker, Starting MySQL, and Connecting using MySQL Shell

First, you grab Docker: https://docs.docker.com/install .

Then, you pull and run MySQL 8.0 (Linux) by running the following.  Note that I’m not using a password which is just for testing a fleeting MySQL Docker container:

$ docker run –name mysql8 -e MYSQL_ALLOW_EMPTY_PASSWORD=yes -d mysql/mysql-server

Unable to find image ‘mysql/mysql-server:latest’ locally

…

Pull complete

…

The Call For Papers  for the next Southern California Linux Expo aka SCaLE is open and I need your help with the MySQL Track.  We have had a MySQL track for the past few years and this year I have gotten permission from the organizers of SCaLE to get a group of MySQL community members to review the talks for this track.  This year was pretty good but to make 2019 even better we need more submissions from more people AND THIS MEANS YOU!!

The link above has the details on how to register to submit a talk submission and the process is fairly simple.  But if you would like help with your submission, want to 'rubber duck' ideas, or want a quick review before you submission please contact me  (@stoker, david.stokes @ Oracle.com) or find me at a show.

So what type of talks do we need?  We need to cover material …

This release has been superseded by 5.7.23-31.31.2 after a critical regression was found. Please update to the latest release.

Percona is glad to announce the release of Percona XtraDB Cluster 5.7.23-31.31 on September 26, 2018. Binaries are available from the downloads section or from our software repositories.

Percona XtraDB Cluster 5.7.23-31.31 is now the current release, based on the following:

• Percona Server for MySQL 5.7.23
…

Thanks for joining us this week for our webinar on monitoring MySQL, MariaDB, PostgreSQL and MongoDB with freely available community tools and more specifically one: ClusterControl Community Edition. The replay and slides are now available to watch on our website.

Monitoring is essential for operations teams to ensure that databases are up and running. However, as databases are increasingly being deployed in distributed topologies based on replication or clustering, what does it mean to our monitoring infrastructure? Is it ok to monitor individual components of a database cluster, or do we need a more holistic systems approach? Can we rely on SELECT 1 as health check when determining whether a …