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Tibor KoroczIn this blog post, we will show you how to add external exporters to Percona Monitoring and Management (PMM) and monitor various services. Our focus will be on Valkey/Redis, but the principles apply to other technologies as well. PMM uses VictoriaMetrics, which is compatible with Prometheus. Prometheus has numerous exporters that you can use. When […]
Recently I had the opportunity to test a storage device from ScaleFlux called CSD 2000. In this blog post, I will share the results of using it to run MySQL in comparison with an Intel device that had a similar capacity. First of all, why do we need another storage device? Why is ScaleFlux any […]
I was testing the latest Percona XtraDB Cluster 8.0 (PXC) release which has the Galera 4 plugin, and I would like to share my experiences and thoughts on the Streaming Replication feature so far. What Is Streaming Replication, in One Sentence? In Galera 4, the large transaction could split into smaller fragments, and even before […]
In this blog post I would like to give an overview of the most common failover scenarios and operations when using MySQL Group Replication 8.0.19 (aka GR) and Percona XtraDB Cluster 8 (PXC) (which is based on Galera), and explain how each technology handles each situation. I have created a three-node cluster with Group Replication […]
In this two-part blog series, I wanted to cover some failover scenarios with Group Replication. In part one, I will discuss an interesting behavior and performance degradation I discovered while writing these posts. In part two, I will show several failover scenarios and demonstrate how Group Replication handles each situation. The test environment is very […]
Recently I was looking for some simple way to analyze and create graphs from data stored in MySQL tables. I know Grafana can also plot graphs from MySQL tables, but somehow it felt like overkill and you are not using the traditional SQL syntax there. So I was searching for another solution, and it actually […]
Recently I was doing some small testing by using EC2 instances on AWS and I noticed the execution time and performance highly depend on which time of the day I am running my scripts. I was using t3.xlarge instance type as I didn’t need many CPUs and memory for my tests, but from time to […]
In MySQL 8.0.18 there is a new feature called how it works under the hood. The high-level basics are the following: if there is a join, it will create an in-memory hash table based on one of the tables and will read the other table row by row, calculate a hash, and do a lookup […]
In MySQL 8.0.18 there is a new feature called Explain Analyze when for many years we mostly had only the traditional Explain. I know there are different formats, but those based on the same information just show it in a different format with some extra details. But Explain Analyze is a different concept. It is actually […]
Recently I had a customer where every single query was running in a transaction, as well as even the simplest selects. Unfortunately, this is not unique and many connectors like Java love to do that. In their case, the Java connector changed autocommit=off for the connection itself at the beginning, and as these were permanent […]
In this blog post, I am going to show why we have to be careful with stored functions in select list, as a single query can cause thousands of queries in the background if we aren’t cautious. For this example, I am only going to use the SLEEP function to demonstrate the issue, but you […]
Recently I had a case where queries against Aurora Reader were 2-3 times slower than on the Writer node. In this blog post, we are going to discuss why. I am not going to go into the details of how Aurora works, as there are other blog posts discussing that. Here I am only going […]
Recently, I encountered a situation where MySQL gave error messages that I had never seen before:
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2018-12-12T14:36:45.571440Z 0 [ERROR] Error log throttle: 150 'Can't create thread to handle new connection' error(s) suppressed 2018-12-12T14:36:45.571456Z 0 [ERROR] Can't create thread to handle new connection(errno= 11) 2018-12-12T14:37:47.748575Z 0 [ERROR] Error log throttle: 940 'Can't create thread to handle new connection' error(s) suppressed 2018-12-12T14:37:47.748595Z 0 [ERROR] Can't create thread to handle new connection(errno= 11) |
I was thinking maybe we hit some ulimit limitations or similar, but all the usual suspects were set high enough, and we were not even close to them. After googling and discussing with the customer, I found they had […]
Recently, I’ve been working with a customer to evaluate the different cloud solutions for MySQL. In this post I am going to focus on maintenance windows and requirements, and what the different cloud platforms offer. Why is this important at all? Maintenance windows are required so that the cloud provider can do the necessary updates, patches, […]
Parallel replication has been around for a few years now but is still not that commonly used. I had a customer where the master had a very large write workload. The slave could not keep up so I recommended to use parallel slave threads. But how can I measure if it really helps and is […]
Please join Percona’s Architect, Tibi Köröcz as he presents Utilizing ProxySQL for Connection Pooling in PHP on Tuesday August 14, 2018, at 8:00 am PDT (UTC-7) / 11:00 am EDT (UTC-4). Register Now ProxySQL is a very powerful tool, with extended capabilities. This presentation will demonstrate how to use ProxySQL to gain functionality (seamless […]
Including setting up Percona XtraDB Cluster with ProxySQL and PMM Please join Percona’s Architect, Tibi Köröcz as he presents Percona XtraDB Cluster 5.7 Tutorial Part 2 on Wednesday, June 20th, 2018, at 7:00 am PDT (UTC-7) / 10:00 am EDT (UTC-4). Register Now Never used Percona XtraDB Cluster before? This is the webinar for […]
Yes, it does! In this blog post, I am going to share my recent experiences with ProxySQL and how important the database software version number can be. Migration I was working on a migration to Percona XtraDB Cluster (PXC) with ProxySQL, fortunately on a staging environment first so we could catch any issues (like this one). We […]
Please join Percona’s Architect, Tibi Köröcz as he presents Percona XtraDB Cluster 5.7 Tutorial on Wednesday, April 18, 2018, at 7:00 am PDT (UTC-7) / 10:00 am EDT (UTC-4). Never used Percona XtraDB Cluster before? Come join this 45-minute tutorial where we will introduce you to the concepts of a fully functional Percona XtraDB Cluster. In this […]
In this blog post, we’ll compare the performance of pattern matching queries vs. full-text indexes. In my previous blog post, I looked for a solution on how we can search only a part of the email address and how can we make faster queries where the condition is email LIKE ‘%n.pierre%’. I showed two possible […]