Recently, we initiated a new project, the Open Source Database Community Blog. One way to think of this is as an online, year round version of the Percona Live conferences. If you have a story to tell, an experience to share, or a lesson to be learned send it along. As long as it’s related to open source database software, their management and application. That’s right. Not just Percona software. Any open source database software of all formats.

Unlike Percona Live, though, we are not limited by time or space. All submissions are welcome as long as they follow some simple guidelines.

We have already had some excellent posts, and in case this is news to you, here’s a recap:

• Renato Losio wrote this succinct how-to article …

In Percona Monitoring and Management (PMM) 1.13 we have adopted Prometheus 2, and with this comes a dramatic improvement in resource usage, along with performance improvements!

What does it mean for you? This means you can have a significantly larger number of servers and database instances monitored by the same PMM installation. Or you can reduce the instance size you use to monitor your environment and save some money.

Let’s look at some stats!

CPU Usage

We can see an approximate 5x and 8x reduction of CPU usage on these two PMM Servers. Depending on the workload, we see CPU usage reductions to range between 3x and 10x.

Disk Writes

There is also less disk write bandwidth required:

On this instance, the bandwidth reduction is “just” 1.5x times. …

In this blog post, we’ll discuss how to set a replication from MySQL 8.0 to MySQL 5.7. There are some situations that having this configuration might help. For example, in the case of a MySQL upgrade, it can be useful to have a master that is using a newer version of MySQL to an older version slave as a rollback plan. Another example is in the case of upgrading a master x master replication topology.

Officially, replication is only supported between consecutive major MySQL versions, and only from a lower version master to a higher version slave. Here is an example of a supported scenario:

5.7 master –> 8.0 slave

while the opposite is not supported:

8.0 master –> 5.7 slave

In this blog post, I’ll walk through how to overcome the …

The main focus of a previous blog post was the performance of MyRocks when using fast SSD devices. However, I figured that MyRocks would be beneficial for use in cloud workloads, where storage is either slow or expensive.

In that earlier post, we demonstrated the benefits of MyRocks, especially for heavy IO workloads. Meanwhile, Mark wrote in his blog that the CPU overhead in MyRocks might be significant for CPU-bound workloads, but this should not be the issue for IO-bound workloads.

In the cloud the cost of resources is a major consideration. Let’s review the annual cost for the processing and storage …

Please join Percona’s CEO, Peter Zaitsev as he presents Using MySQL for Distributed Database Architectures on Tuesday, July 31st, 2018 at 7:00 AM PDT (UTC-7) / 10:00 AM EDT (UTC-4).

Register Now

In modern data architectures, we’re increasingly moving from single-node design systems to distributed architectures using multiple nodes – often spread across multiple databases and multiple continents. Such architectures bring many benefits (such as scalability and resiliency), but can also bring a lot of pain if incorrectly designed and …

The choice of good InnoDB primary keys is a critical performance tuning decision. This post will guide you through the steps of choosing the best primary key depending on your workload.

As a principal architect at Percona, one of my main duties is to tune customer databases. There are many aspects related to performance tuning which make the job complex and very interesting. In this post, I want to discuss one of the most important one: the choice of good InnoDB primary keys. You would be surprised how many times I had to explain the importance of primary keys and how many debates I had around the topic as often people have preconceived ideas that translate into doing things a certain way without further thinking.

The choice of a good primary key for an InnoDB table is extremely important and can have huge performance impacts. When you start working with a customer using an overloaded x1.16xlarge RDS instance, with close …

Please join Percona Senior MySQL DBA for Managed Services, Dov Endress, as he presents XA Transactions on Wednesday, July 25th, 2018 at 12:00 PM PDT (UTC-7) / 3:00 PM EDT (UTC-4).

Register Now

Distributed transactions (XA) are becoming more and more vital as applications evolve. In this webinar, we will learn what distributed transactions are and how MySQL implements the XA specification. We will learn the investigatory and debugging techniques necessary to ensure high availability and data consistency across disparate environments.

This webinar is not intended to be an in-depth look at transaction managers, but focuses on resource managers only. It is primarily intended for database administrators and site reliability engineers.

…

Welcome to the third part of this series. I’m glad you’re still reading, as hopefully this means you find this subject interesting at least. Previously we presented the first two components of MySQL InnoDB Cluster: Group Replication and MySQL Router and now we will discuss the last component, MySQL Shell.

MySQL Shell

This is the last component in the cluster and I love it. Oracle have created this tool to centralize cluster management, providing a friendly, command-line based user interface.

The tool can be defined as an advanced MySQL shell, which is much more powerful than the well known MySQL client. With the capacity to work …

Please join Percona’s Chief Evangelist, Colin Charles as he presents as he presents MariaDB 10.3 vs. MySQL 8.0 on Wednesday, July 18th, 2018, at 9:00 AM PDT (UTC-7) / 12:00 PM EDT (UTC-4).

Register Now

Technical considerations

Are they syntactically similar? Where do these two databases differ? Why would I use one over the other?

MariaDB 10.3 is on the path of gradually diverging from MySQL 8.0. One obvious example is the internal data dictionary currently under development for MySQL 8.0. This is a major change to the way metadata is stored and used within the server, and MariaDB doesn’t have an equivalent feature. Implementing this feature could mark the end of datafile-level compatibility between …

If you’re reading consumer SSD reviews and using them to estimate SSD performance under database workloads, you’d better stop. Databases are not your typical consumer applications and they do not use IO in the same way.

Let’s look, for example, at this excellent AnandTech review of Samsung 960 Pro –  a consumer NVMe device that I happen to have in my test lab.

The summary table is actually great, showing the performance both at Queue Depth 1 (single threaded) as well as Queue Depth 32 – a pretty heavy concurrent load.

Even at QD1 we see 50K (4K) writes per second, which should be enough for pretty serious database workloads.

In reality, though, you might be in for some disappointing surprises. While “normal” buffered IO is indeed quite fast, this drive really hates fsync() calls, with a single thread …