The latest from the MySQL community

Percona announces the GA release of Percona Server for MySQL 5.7.22-22 on on May 31, 2018. Download the latest version from the Percona web site or the Percona Software Repositories. You can also run Docker containers from the images in the Docker Hub repository.

Based on MySQL 5.7.22, including all the bug fixes in it, Percona Server for MySQL 5.7.22-22 is the current GA release in the Percona Server for MySQL 5.7 series. Percona …

At my latest webinar “MySQL Test Framework (MTR) for Troubleshooting”, I received an interesting question about MTR test cases for Percona XtraDB Cluster (PXC). Particularly about testing SST and IST.

This post is intended to answer this question. It assumes you are familiar with MTR and can write tests for MySQL servers. If you are not, please watch the webinar recording first.

You can find example tests in any PXC tarball package. They are located in directories

mysql-test/suite/galera

 ,

mysql-test/suite/galera_3nodes

  and

mysql-test/suite/wsrep

 , though that last directory only contains a configuration file.

If you …

This is our fourth blog in the ProxySQL Series

1. MySQL Replication Read-write Split up
2. Seamless Replication Switchover Using MHA
3. Mirroring MySQL Queries

This blog focuses on how to quickly find and address badly written queries using ProxySQL without any downtime and change in application code.

When we get an incident about the high usage on a production master, then mostly it is because of unexpected spike in Traffic (QPS) or slow queries.

Below was the status when we were doing the …

We have identified an issue in a script that is executed as part of the Tungsten Clustering solution. The script itself executes a small query against the internal tables used by the replicator in order to help identify the current status and latency of the replication process. We believe this script may occasionally fail under some very specific conditions, which would not normally be an issue, but the knock on effect is to create Out of Memory errors and instability in the way identifying the current replication state is handled.

The issue has been fixed in the upcoming 6.0.1 and 5.3.2 releases, but we have identified that customers on versions of the Tungsten Clustering solution from v4.0 upwards would benefit from using an updated version of the script.

If you are using Tungsten Clustering 4.x or higher, it is recommended that you apply this patch to improve the stability of your clustering …

In this blog post, I will show you how easy it is to set up a Percona Monitoring and Management server on Google Compute Engine from the command line.

First off you will need to have a Google account and install the Cloud SDK tool. You need to create a GCP (Google Cloud Platform) project and enable billing to proceed. This blog assumes you are able to authenticate and SSH into instances from the command line.

Here are the steps to install PMM server in Google Cloud Platform.

1) Create the Compute engine instance with the following command. The example creates an Ubuntu Xenial 16.04 LTS compute instance in the us-west1-b zone with a 100GB persistent disk. For production systems it would be best to use a 500GB disk instead (size=500GB). This should be …

Percona Monitoring and Management (PMM) is a free and open-source platform for managing and monitoring MySQL® and MongoDB® performance. You can run PMM in your own environment for maximum security and reliability. It provides thorough time-based analysis for MySQL® and MongoDB® servers to ensure that your data works as efficiently as possible.

In PMM Release 1.11.0, we deliver the following changes:

• Configurable MySQL Slow Log Rotation – enable or disable rotation, and specify how many files to keep on disk
• Predictable Graphs – we’ve updated our formulas to use aggregation functions over time for more reliable graphs
• MySQL Exporter Parsing of my.cnf – we’ve improved how we read my.cnf
• Annotation improvements – passing …

In this article, I’ll explain about the multi version concurrency control (MVCC) of large objects (LOBs) design in the MySQL InnoDB storage engine.  MySQL 8.0 has a new feature that allows users to partially update large objects, including the JSON documents.  …

The UTF-8 is a variable-length encoding.  In the case of UTF-8, it means that storing one code point requires one to four bytes. But, In MySQL’s encoding called “utf8” only stores a maximum of three bytes per code point. In the modern web / mobile applications, we have to support for storing not only language characters but also symbols and emojis, Let me show you below some very weird issues faced using MySQL “utf8” :

mysql> SET NAMES utf8; # just to emphasize that the connection charset is set to `utf8`
Query OK, 0 rows affected (0.00 sec)

mysql> UPDATE custfeeds.reactions SET reacted = 'super like ' WHERE id = 13015;
Query OK, 1 row affected, 1 warning (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 1

mysql> SELECT reactions FROM custfeeds.reactions WHERE id = 13015;
+-------------+
| reactions   |
+-------------+
| super liked |
+-------------+
1 row in set (0.00 sec)


mysql> SHOW WARNINGS; …

Working with databases, concurrency control is the concept that ensures that database transactions are performed concurrently without violating data integrity.

There is a lot of theory and different approaches around this concept and how to accomplish it, but we will briefly refer to the way that PostgreSQL and MySQL (when using InnoDB) handle it, and a common problem that can arise in highly concurrent systems: deadlocks.

These engines implement concurrency control by using a method called MVCC (Multiversion Concurrency Control). In this method, when an item is being updated, the changes will not overwrite the original data, but instead a new version of the item (with the changes) will be created. Thus we will have several versions of the item …

MySQL, coupled with the InnoDB engine, provides full ACID compliance. With the addition of “eXtended Architecture” (XA) technology, they can all act in a distributed atomic environment.

In distributed systems, several different technologies, platforms and devices may need to act on separate sets of data atomically. These backend datasets can exist side by side in a datacenter, or across oceans. There can be multiple datasets where atomicity is a necessity. Foreign engines could completely control these datasets, with no concept of cross communication. The XA standard was specified by the Open Group to describe distributed transaction processing. This “eXtended Architecture” describes the relationship between a transaction manager and a transaction resource. You can find the specification HERE.

Transactions are:

• ATOMIC, committed as a …