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Showing entries 1 to 10 of 234 10 Older Entries

Displaying posts with tag: Benchmarks (reset)

Measuring the impact of tcpdump on Very Busy Hosts
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A few years back Deva wrote about how to use tcpdump on very busy hosts. That post sparked my interest about exploring how to measure the impact of tcpdump on very busy hosts. In this post, I wanted to highlight how much of an impact there really is and what options you have to make the query collection much more effective.

Some things you need to know:

  • The test is a sysbench read-only workload, 8 tables, 8 threads, 1000000 rows each with 16G of buffer pool. Dataset fully in memory.
  • sysbench …
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Is MySQL’s innodb_file_per_table slowing you down?
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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 …

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MySQL benchmarks on eXFlash DIMMs
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In this blog post, we will discuss MySQL performance on eXFlash DIMMs. Earlier we measured the IO performance of these storage devices with sysbench fileio.

Environment

The benchmarking environment was the same as the one we did sysbench fileio in.

CPU: 2x Intel Xeon E5-2690 (hyper threading enabled)
FusionIO driver version: 3.2.6 build 1212
Operating system: CentOS 6.5
Kernel version: 2.6.32-431.el6.x86_64

In this case, we used a separate machine for testing which had a 10G ethernet …




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Importing big tables with large indexes with Myloader MySQL tool
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Mydumper is known as the faster (much faster) mysqldump alternative. So, if you take a logical backup you will choose Mydumper instead of mysqldump. But what about the restore? Well, who needs to restore a logical backup? It takes ages! Even with Myloader. But this could change just a bit if we are able to take advantage of Fast Index Creation.

As you probably know, Mydumper and mysqldump export the struct of a table, with all the indexes and the constraints, and of course, the data. Then, Myloader and MySQL import the struct of the table and import the data. The most important difference is that you can configure Myloader to …

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Looking deeper into InnoDB’s problem with many row versions
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A few days ago I wrote about MySQL performance implications of InnoDB isolation modes and I touched briefly upon the bizarre performance regression I found with InnoDB handling a large amount of versions for a single row. Today I wanted to look a bit deeper into the problem, which I also filed as a bug.

First I validated in which conditions the problem happens. It seems to happen only in REPEATABLE-READ isolation mode and only …

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Hyper-threading – how does it double CPU throughput?
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The other day a customer asked me to do capacity planning for their web server farm. I was looking at the CPU graph for one of the web servers that had Hyper-threading switched ON and thought to myself: “This must be quite a misleading graph – it shows 30% CPU usage. It can’t really be that this server can handle 3 times more work?”

Or can it?

I decided to do what we usually do in such case – I decided to test it and find out the truth. Turns out – there’s more to it than meets the eye.

How Intel Hyper-Threading works

Before we get to my benchmark results, …


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MySQL performance implications of InnoDB isolation modes
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Over the past few months I’ve written a couple of posts about dangerous debt of InnoDB Transactional History and about the fact MVCC can be the cause of severe MySQL performance issues. In this post I will cover a related topic – InnoDB Transaction Isolation Modes, their relationship with MVCC (multi-version concurrency control) and how they impact MySQL performance.

The …

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How small changes impact complex systems – MySQL example
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If you’ve been studying complex systems you know what minor changes might cause consequences of much greater proportions, sometimes causing some effects that are not easily explained at first. I recently ran across a great illustration of such behavior while doing MySQL benchmarks which I thought would be interesting to share.

I’m using a very simple benchmark – Sysbench 0.5 on Percona Server 5.6.21-70.1 just running update queries:

sysbench  --num-threads=64 --report-interval=10 --max-time=0 --max-requests=0 --rand-type=pareto --oltp-table-size=1000000000 --mysql-user=root --mysql-password= --mysql-db=sbinnodb …
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Streamlined Percona XtraDB Cluster (or anything) testing with Consul and Vagrant
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Introducing Consul

I’m always interested in what Mitchell Hashimoto and Hashicorp are up to, I typically find their projects valuable.  If you’ve heard of Vagrant, you know their work.

I recently became interested in a newer project they have called ‘Consul‘.  Consul is a bit hard to describe.  It is (in part):

  • Highly consistent metadata store (a bit like Zookeeeper)
  • A monitoring system (lightweight Nagios)
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MySQL benchmarking: Know your baseline variance!
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Often enough I find MySQL benchmark results where the difference between results is 1% or even less and some conclusions are drawn. Now it is not that 1% is not important – especially when you’re developing the product you should care about those 1% improvements or regressions because they tend to add up. However with such a small difference it is very important to understand whenever this is for real or it is just the natural variance for your baseline test.

Take a look at this graph:
Click the image for a larger view)

 


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Showing entries 1 to 10 of 234 10 Older Entries

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