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Displaying posts with tag: Benchmarking (reset)
Antijoin in MySQL 8

In MySQL 8.0.17, we made an observation in the well-known TPC-H benchmark for one particular query. The query was executing 20% faster than in MySQL 8.0.16. This improvement is because of the “antijoin” optimization which I implemented. Here is its short mention in the release notes:

“The optimizer now transforms a WHERE condition having NOT IN (subquery), NOT EXISTS (subquery), IN (subquery) IS NOT TRUE, or EXISTS (subquery) IS NOT TRUE internally into an antijoin, thus removing the subquery.”

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Putting Galera SST Compression on the benchmark

I mentioned in my Galera crash (un)safe post that it’s bad if a SST is triggered on a large dataset. On a Galera node an SST will simply wipe the contents of the MySQL data directory and copy a snapshot from another node in the cluster. For consistency this is a favorable thing to do, but from an HA perspective it isn’t: one node in the cluster is unavailable and another one is acting as donor. This means, if you have a three node Galera cluster, only two are available where one has “degraded” performance.

This could have quite high impact, for instance in the proxysql_galera_checker script only synced nodes are selected to receive traffic. By default the donor nodes will not receive any traffic and now the cluster only has one node left to serve traffic. Don’t worry: if there are no synced …

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Hyperconverging and Galera cluster

What is hyperconverging?

Hyperconverging is the latest hype: do things more efficiently with the resources that you have by cramming as many virtual machines on the same hypervisor. In theory this should allow you to mix and match various workloads to make the optimum use of your hypervisor (e.g. all cores used 100% of the time, overbooking your memory up to 200%, moving virtuals around like there is no tomorrow). Any cloud provider is hyperconverging their infrastructure and this has pros and cons. The pro is that it’s much cheaper to run many different workloads while the con clearly is when you encounter noisy neighbors. As Jeremy Cole said: “We are utilizing our virtual machines to the max. If you are on the same hypervisor as us, sorry!”

Apart from cloud providers, you could hyperconverge your infrastructure yourself. There are a few hardware/software vendors out there that will help you with that and at one of my …

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Dynimize + MySQL Cross-Microarchitecture Analysis

In this blog post I will discuss how the Dynimize cross microarchitecture performance results were obtained, followed by an analysis of these results.

You can download the scripts to generate similar graphs for your own system from here. Note this repository also contains the results generated for all the tests performed. A trace of the script executing each command was generated by using #!/bin/bash -x, and saved in the output.log files. A full run across all 5 benchmarks takes approximately 2 hrs on the systems I used.


In order to use these scripts, you must first install Dynimize:

wget -O install
wget  …

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MySQL with Docker – Performance characteristics

Docker presents new levels of portability and ease of use when it comes to deploying systems. We have for some time now released Dockerfiles and scripts for MySQL products, and are not surprised by it steadily gaining traction in the development community.…

AWS Aurora Benchmarking part 2

Some time ago, I published the article on AWS Aurora Benchmarking (AWS Aurora Benchmarking – Blast or Splash?), in which I analyzed the behavior of different solutions using synchronous replication in AWS environment. This blog follows up with some of the comments and suggestions I received regarding that post from the community and Amazon engineers.

I decided to perform another round of tests, keeping in mind comments and suggestions received.

I presented some of the results during the Percona conference in Santa Clara last April 2016. The following is the transposition that presentation, with more details.

Not interested in the preliminary descriptions? Go to the results section

Why new tests?

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MySQL 5.7 Labs — Using Loopback Fast Path With Windows 8/2012

TCP Loopback fast path

In Windows 8 and Windows server 2012, Microsoft introduced a new “TCP Loopback fast path” feature (see the Microsoft Technet article: Fast TCP Loopback Performance and Low Latency with Windows Server 2012 TCP Loopback Fast Path).…

Performance Schema: Great Power Comes Without Great Cost

Performance Schema is used extensively both internally and within the MySQL community, and I expect even more usage with the new SYS Schema and the Performance Schema enhancements in 5.7. Performance Schema is the single best tool available for monitoring MySQL Server internals and execution details at a lower level. Having said that, we are also no stranger to the fact that any monitoring tool comes with an additional cost to performance. Hence It has always been an important question to find out just how much it costs us when Performance …

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Performance Impact of InnoDB Transaction Isolation Modes in MySQL 5.7

During the process of reviewing our server defaults for MySQL 5.7, we thought that it might be better to change the default transaction isolation level from REPEATABLE-READ to READ-COMMITTED (the default for PostgreSQL, Oracle, and SQL Server). After some benchmarking, however, it seems that we should stick with REPEATABLE-READ as the default for now.

It’s very easy to modify the default isolation level, however, and it can even be done at the SESSION level. For the most optimal performance you can change the transaction isolation level dynamically in your SESSION according …

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Is MySQL’s innodb_file_per_table slowing you down?

MySQL’s innodb_file_per_table is a wonderful thing – most of the time. Having every table use its own .ibd file allows you to easily reclaim space when dropping or truncating tables. But in some use cases, it may cause significant performance issues.

Many of you in the audience are responsible for running automated tests on your codebase before deploying to production. If you are, then one of your goals is having tests run as quickly as possible so you can run them as frequently as possible. Often times you can change specific settings in your test environment that don’t affect the outcome of the test, but do improve throughput. This post discusses how innodb_file_per_table is one of those settings.

I recently spoke with a customer whose use case involved creating hundreds of tables on up to 16 schemas …

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