In April 2021, I wrote an article about Online DDL and Group Replication. At that time we were dealing with MySQL 8.0.23 and also opened a bug report which did not have the right answer to the case presented. 

Anyhow, in that article I have shown how an online DDL was de facto locking the whole cluster for a very long time even when using the consistency level set to EVENTUAL.

This article is to give justice to the work done by the MySQL/Oracle engineers to correct that annoying inconvenience. 

Before going ahead, let us remember how an Online DDL was propagated in a group replication cluster, and identify the differences with what happens now, all with the consistency level set to EVENTUAL ( …

Security will always be a main focal point of a company’s data. A common question I get from clients is, “how do I enable encryption?” Like every good consulting answer, it depends on what you are trying to encrypt. This post is a high-level summary of the different options available for encryption in Percona Server for MySQL.

Different certifications require different levels of encryption. For example, PCI requires both encryptions of data at rest and in transit. Here are the main facets of encryption for MySQL:

• Data at Rest
  • Full disk encryption (at the OS level)
  • Transparent Data Encryption – TDE
  • Column/field-level encryption
• Data in Transit
  • TLS Connections

Data at Rest

…

In this blog post, we will compare the performance of performing a backup from a MySQL database using mysqldump, MySQL Shell feature called Instance Dump, mysqlpump, mydumper, and Percona XtraBackup. All these available options are open source and free to use for the entire community.

To start, let’s see the results of the test.

Benchmark Results

The benchmark was run on an …

Percona XtraDB Cluster 8.0.25 (PXC) has introduced a new option to perform online schema modifications: NBO (Non-Blocking Operation).

When using PXC, the cluster relies on the wsrep_OSU_method parameter to define the Online Schema Upgrade (OSU) method the node uses to replicate DDL statements. 

Until now, we normally have three options:

• Use Total Isolation Order (TOI, the default)
• Use Rolling Schema Upgrade (RSU)
• Use Percona’s online schema change tool (TOI + PTOSC)

Each method has some positive and negative aspects. TOI will lock the whole …

We have a quickstart guide for how to install Percona Distribution for MySQL Operator on minikube. Installing the minimal version works well as it is described in the guide. After that, we will have one HAproxy and one Percona XtraDB Cluster (PXC) node to work with.

Minikube provides Kubernetes locally. One can try using the provided local k8s to try the more advanced scenarios such as the one described here.

Following that guide, everything works well, until we get to the part of deploying a cluster with

deploy/cr.yaml

Even after that, things seemingly work.

$ kubectl get pods
NAME READY STATUS RESTARTS AGE …

Working on a real case scenario in a five node Percona XtraDB Cluster (PXC), we were forced to use wsrep_sync_wait = 1, because the app does reads-after-write and we send reads to all the nodes. We had the idea to leave some nodes in DESYNC mode to reduce the flow control messages during peak load and expected to have a steadier write throughput keeping the read consistency.

We decided to test Perconas’s new PXC Scheduler Handler which is an application that manages integration between ProxySQL and Galera/PXC (the scope is to maintain the ProxySQL mysql_server table, if a negative scenario occurs, like: failures, service degradation, and maintenance). However, we realized that when a node is in DESYNC mode, it is kicked out of the read hostgroup. That is …

There are plenty of ways to run ProxySQL in Kubernetes (K8S). For example, we can deploy sidecar containers on the application pods, or run a dedicated ProxySQL service with its own pods.

We are going to discuss the latter approach, which is more likely to be used when dealing with a large number of application pods. Remember each ProxySQL instance runs a number of checks against the database backends. These checks monitor things like server-status and replication lag. Having too many proxies can cause significant overhead.

Creating a Cluster

For the purpose of this example, I am going to deploy a test cluster in GKE. We need to follow these steps:

1. Create a cluster

gcloud container clusters create ivan-cluster --preemptible --project my-project --zone us-central1-c --machine-type n2-standard-4 --num-nodes=3

2. Configure command-line access

gcloud …

As we’ve communicated in our blog post in May, the TokuDB Storage Engine has been marked as “deprecated” in Percona Server for MySQL 8.0. It will be removed in a future version (Percona Server for MySQL 8.0.28, expected to ship in Q1 2022).

With the release of Percona Server for MySQL 8.0.26, the storage engine will still be included in the binary builds and packages but will be disabled by default. If you are upgrading from a previous version, the TokuDB Storage Engine plugin will fail with an error message at server startup if it is installed.

You will still be able to re-enable it manually so that you can perform the necessary migration steps.

Re-enabling the TokuDB …

It is a common use case to synchronize data in two tables inside MySQL servers. This blog post describes one specific case: how to synchronize data between two different tables on the same MySQL server. This could be useful, for example, if you test DML query performance and do not want to affect production data. After few experiments, tables get out of sync and you may need to update the test one to continue working on improving your queries. There are other use cases when you may need to synchronize the content of the two different tables on the same server, and this blog will show you how to do it.

Table Content Synchronization

The industry-standard tool for table content synchronization – pt-table-sync – is designed to synchronize data between different MySQL servers and does not support bulk synchronization between two …

As a Technical Account Manager at Percona, I get to work with many of our largest clients. While the industry verticals vary, one main core challenge generally remains the same – what do I do with all this data? Dealing with massive data sets in MySQL isn’t a new challenge, but the best approach still isn’t trivial. Each application is obviously different, but I wanted to discuss some of the main best practices around dealing with lakes of data.

Keep MySQL Instances Small

First and foremost, the architecture needs to be designed to keep each MySQL instance relatively small. A very common question I get from teams new to working with MySQL is: “So what is the largest instance size MySQL supports?”. My answer goes back to my time in consulting: “It depends”. Can my MySQL instance support a 20TB dataset? Maybe, but it depends on the workload pattern. Should I store 20TB of data in a single MySQL instance? In most cases, …