MySQL 8 introduced a number of enhancements to improve both replication performance and the monitoring thereof. Improvements included more efficient replication of small updates on big JSON documents, the addition of Performance Schema tables for slave performance metrics, tracing and debug logging improvements, among others. With regards to monitoring, Group Replication has been improved by introducing new replication timestamps, additional columns to the performance schema, as well as by making the relationship between replication threads more efficient. We covered the various improvements to replication performance in the Replication Performance Enhancements in MySQL 8 blog. Today’s blog will provide some practical guidelines on monitoring your MySQL 8 master-slave and group (cluster) replication.

Two Types of MySQL Replication …

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

There have been two big pieces of news this week: the release of MongoDB 4.0 and the fact that Facebook has migrated the Messenger backend over to MyRocks.

MongoDB 4.0 is stable, with support for multi-document ACID transactions. I quite like the engineering chalk and talks videos on the transactions page. There are also improvements to help manage your MongoDB workloads in a Kubernetes cluster. MongoDB Atlas supports global clusters (geographically distributed databases, low latency writes, and data placement controls for regulatory …

Percona announces the release of Percona XtraDB Cluster 5.7.22-29.26 (PXC) on June 29, 2018. Binaries are available from the downloads section or our software repositories.

Percona XtraDB Cluster 5.7.22-29.26 is now the current release, based on the following:

• Percona Server for MySQL 5.7.22
• Galera/Codership WSREP API Release 5.7.21
• Galera Replication library 3.23

Deprecated

The following variables …

In MySQL 8.0 there are two new features designed to support lock handling: NOWAIT and SKIP LOCKED. In this post, we’ll look at how MySQL 8.0 handles hot rows. Up until now, how have you handled locks that are part of an active transaction or are hot rows? It’s likely that you have the application attempt to access the data, and if there is a lock on the requested rows, you incur a timeout and have to retry the transaction. These two new features help you to implement sophisticated lock handling scenarios allowing you to handle timeouts better and improve the application’s performance.

To demonstrate I’ll use this product table.

mysql> select @@version;
+-----------+
| @@version |
+-----------+
| 8.0.11    |
+-----------+
1 row in set (0.00 sec)

CREATE TABLE `product` (
`p_id` int(11) NOT NULL AUTO_INCREMENT,
`p_name` varchar(255) DEFAULT NULL,
`p_cost` decimal(19,4) NOT NULL,
`p_availability` enum('YES','NO') …

MariaDB 10.3 is now generally available (10.3.7 was released GA on 2018-05-25). The article What’s New in MariaDB Server 10.3 by the MariaDB Corporation lists three key improvements in 10.3: temporal data processing, Oracle compatibility features, and purpose-built storage engines. Even if I am excited about MyRocks and curious on Spider, I am also very interested in less flashy but still very important changes that make running the database in production easier. This post describes such improvement: no InnoDB Buffer Pool in core dumps.

Hidden in the …

Troubleshooting crashes is never a fun task, especially if MySQL does not report the cause of the crash. For example, when MySQL runs out of memory. Peter Zaitsev wrote a blog post in 2012: Troubleshooting MySQL Memory Usage with a lots of useful tips. With the new versions of MySQL (5.7+) and performance_schema we have the ability to troubleshoot MySQL memory allocation much more easily.

In this blog post I will show you how to use it.

First of all, there are 3 major cases when MySQL will crash due to running out of memory:

1. MySQL tries to allocate more memory than available because we specifically told it to do so. For example: you did not set innodb_buffer_pool_size correctly. This is very easy to fix
2. There is some other process(es) on the server that allocates RAM. It can be the application …

Galera Cluster comes with many notable features that are not available in standard MySQL replication (or Group Replication); automatic node provisioning, true multi-master with conflict resolutions and automatic failover. There are also a number of limitations that could potentially impact cluster performance. Luckily, if you are not aware of these, there are workarounds. And if you do it right, you can minimize the impact of these limitations and improve overall performance.

We have previously covered many tips and tricks related to Galera Cluster, including running Galera on AWS Cloud. This blog post distinctly dives into the performance aspects, with examples on how to get the most out of Galera.

Replication Payload

A …

PMM (Percona Monitoring and Management) 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 release 1.12, we invested our efforts in the following areas:

• Visual Explain in Query Analytics – Gain insight into MySQL’s query optimizer for your queries
• New Dashboard – InnoDB Compression Metrics – Evaluate effectiveness of InnoDB Compression
• New Dashboard – MySQL Command/Handler Compare – Contrast MySQL instances side by side
• Updated …

As promised, here is a post more detailed on how to create a MySQL InnoDB Cluster using MySQL Shell and the AdminAPI.

First of all, as a good practice is never enough repeated, whatever the version of MySQL you are using, please use the latest MySQL Shell ! So if you are using 5.7, please use MySQL Shell 8.0.11. See this compatibility matrix or this official one.

dba class

The AdminAPI can be accessed by the MySQL Shell via the dba object. The reference manual for this class is here. The Shell …

Database schema is not something that is written in stone. It is designed for a given application, but then the requirements may and usually do change. New modules and functionalities are added to the application, more data is collected, code and data model refactoring is performed. Thereby the need to modify the database schema to adapt to these changes; adding or modifying columns, creating new tables or partitioning large ones. Queries change too as developers add new ways for users to interact with the data - new queries could use new, more efficient indexes so we rush to create them in order to provide the application with the best database performance.

So, how do we best approach a schema change? What tools are useful? How to minimize the impact on a production database? What are the most common issues with schema design? What tools can help you to stay on top of your schema? In this blog post we will give you a short overview of how …