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Displaying posts with tag: Performance (reset)
MyISAM and KPTI – Performance Implications From The Meltdown Fix

Recently we had a report from a user who had seen a stunning 90% performance regression after upgrading his server to a Linux kernel with KPTI (kernel page-table isolation – a remedy for the Meltdown vulnerability). A big deal of those 90% was caused by running in an old version of VMware which doesn’t pass […]

The post MyISAM and KPTI – Performance Implications From The Meltdown Fix appeared first on MariaDB.org.

Choosing the best indexes for MySQL query optimization

Many of our users, developers and database administrators, keep asking our team about EverSQL’s indexing recommendations algorithm.

So, we decided to write about it.

This tutorial won’t detail all the internals of the algorithm, but rather try to lay down the basic and important aspects of indexing, in simple terms.
Also, and most importantly, we’ll present practical examples for properly indexing your tables and queries by relying on a set of rules, rather than on guessing.

Our focus in this tutorial is on MySQL, MariaDB and PerconaDB databases. This information may be relevant for other database vendors as well, but in some cases may not.

Which indexes should I create for an SQL query?

As a general rule of thumb, MySQL can only use on index for each table in the query. Therefore, there is no point in creating more than one index for each query. Preferably, same indexes should match as …

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MySQL Query Performance: Not Just Indexes

In this blog post, I’ll look at whether optimizing indexing is always the key to improving MySQL query performance (spoiler, it isn’t).

As we look at MySQL query performance, our first concern is often whether a query is using the right indexes to retrieve the data. This is based on the assumption that finding the data is the most expensive operation – and the one you should focus on for MySQL query optimization. However, this is not always the case.

Let’s look at this query for illustration:

mysql> show create table tbl G
*************************** 1. row ***************************
      Table: tbl
Create Table: CREATE TABLE `tbl` (
 `id` int(11) NOT NULL AUTO_INCREMENT,
 `k` int(11) NOT NULL DEFAULT '0',
 `g` int(10) unsigned NOT NULL,
 PRIMARY KEY (`id`),
 KEY `k_1` (`k`)
) ENGINE=InnoDB …
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Webinar Thursday, January 25, 2018: Troubleshooting MySQL Crashes

Please join Percona’s Principal Support Engineer, Sveta Smirnova, as she presents Troubleshooting MySQL Crashes on January 25, 2018, at 10:00 am PST (UTC -8) / 1:00 pm EST (UTC -5).

Register Now

 

This webinar is for every MySQL user! In this talk, I won’t focus on how to analyze core files, read the source code or set breakpoints. Instead, I will focus on techniques that are available to anyone, even a novice.

Many tutorials, including my own, written based on Roel Van de Paar’s video, suggest how to create and analyze core files created at the time of a crash. While this …

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Does the Meltdown Fix Affect Performance for MySQL on Bare Metal?

In this blog post, we’ll look at does the Meltdown fix affect performance for MySQL on bare metal servers.

Since the news about the Meltdown bug, there were a lot of reports on the performance hit from proposed fixes. We have looked at how the fix affects MySQL (Percona Server for MySQL) under a sysbench workload.

In this case, we used bare metal boxes with the following specifications:

  • Two-socket Intel(R) Xeon(R) CPU E5-2683 v3 @ 2.00GHz (in total 56 entries in /proc/cpuinfo)
  • Ubuntu 16.04
  • Memory: 256GB
  • Storage: Samsung SM863 1.9TB SATA SSD
  • Percona Server for MySQL 5.7.20
  • Kernel (vulnerable) 4.13.0-21
  • Kernel (with Meltdown fix) 4.13.0-25

Please note, the current kernel for Ubuntu 16.04 contains only a Meltdown fix, …

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Measuring the potential overhead of PMM Client on MySQL workloads

Having good historial metrics monitoring in place is critical for properly operating, maintaining and troubleshooting database systems, and Percona Monitoring and Management is one of the options we recommend to our clients for this.

One common concern among potential users is how using this may impact their database’s performance. As I could not find any conclusive information about this, I set out to do some basic tests and this post shows my results.

To begin, let me describe my setup. I used the following Google Cloud instances:

  • One 4 vCPU instance for the MySQL server
  • One 2 vCPU instance for the sysbench client
  • One 1 vCPU instance for the PMM server

I used Percona Server 5.7 and PMM 1.5.3 installed via Docker. Slow query log was enabled with long_query_time set to 0 …

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Top 10 things to know about Alibaba Cloud RDS

Cloud-based Relational Database Services (RDS) offer businesses a variety of traditional Relational Database Management Systems (RDBMS) with several management and configuration options. In the Top 10 Things to Know about Amazon RDS blog, we covered Amazon RDS. In today’s article, we’ll be presenting Alibaba Cloud RDS. If you’ve been considering moving some or all of your database infrastructure to Alibaba Cloud RDS, or any Cloud RDS for that matter, there are many things to consider. Here are the top 10 things you need to know before taking the plunge.

About Alibaba Cloud RDS

Alibaba Cloud RDS, whose full name is Alibaba Cloud ApsaraDB for RDS, is an on-demand database service that handles some of the administrative tasks associated with managing a database, thus leaving you with more time to focus on your core business. …

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Possible ways to improve performance if you feel affected by Spectre and Meltdown

If you are concerned by performance degradation caused by Spectre and Meltdown patches it might be a good idea to do a few checks that will boost back your MySQL performance:

- Check if your instance’s CPU are running with full power:

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

if the output is

powersave

You may benefit from setting CPU speed to performance mode

for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance

Please refer to https://wiki.debian.org/HowTo/CpuFrequencyScaling and https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt for more details.

- Check if your MySQL instances are configured properly. Buffer pool should …

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Using ioping to Evaluate Storage Performance for MySQL Workloads

In this blog post, we’ll look at how ioping can be used with other tools to understand and troubleshoot storage performance, specifically as it relates to MySQL workloads.

I recently ran into ioping, a nice little utility by Konstantin Khlebnikov that checks storage latency.  

For me, the main beauty of ioping is its simplicity and familiarity. It takes after the ubiquitous ping tool, but “pings” the storage instead of the network device.

First, let’s talk about what this tool isn’t: it isn’t a benchmark tool to stress load your storage as heavily as possible. For that, you can use iozone or sysbench (among many others). This also isn’t a tool for looking at …

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InnoDB Performance Optimization: Webinar Q & A

Thank you for attending my webinar on Wednesday, December 20, 2017, InnoDB Performance Optimization. In this blog, I will provide answers to the Q & A for the webinar.

Are the T2 CPUs similar to the M4 series?

I would expect them to be similar. Amazon does not disclose what specific version of CPUs they use for T2 instances. More details are available here.

Delay in spinlock code is pretty old code. Need to optimize based on today’s CPU? Your views?

There have been a number of improvements to the InnoDB Spinlock code during the last few years. For example, using CPU …

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