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Displaying posts with tag: Benchmarks (reset)
Investigating MySQL Replication Latency in Percona XtraDB Cluster

Investigating MySQL Replication Latency in Percona XtraDB Cluster

I was curious to check how Percona XtraDB Cluster behaves when it comes to MySQL replication latency — or better yet, call it data propagation latency. It was interesting to see whenever I can get stale data reads from other cluster nodes after write performed to some specific node. To test it I wrote quite a simple script (you can find it in the end of the post) which connects to one node in the cluster, performs an update and then immediately does the read from second node. If the data has been already propagated — good, if not we’ll continue to retry reads until it finally propagates, and then measure the latency. This is used to see whenever application …

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Mystery Performance Variance with MySQL Restarts

Based on a lot of surprising comments about my MySQL 5.5 vs 5.6 performance post I decided to perform deeper investigation to see where my results could go possibly wrong. I had set up everything to be as simple as possible to get maximally repeatable results. I did Read Only ran which is typically a lot more repeatable (though also less relevant for production like workload). I had done number of iterations for benchmark run and I used dedicated physical hardware box so external environment impact often causing problems in Virtualized environments can be eliminated. Still I found there could be large variance between the runs.

I set up the benchmarks run to go over night in the loop, doing the benchmark run for 5 runs when restarting MySQL server and repeating the run. I did it on 2 identical boxes to eliminate faulty hardware as …

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Binlogs 101

The mysqlbinlog are not new. We often reference it and all of the valuable information that it provides. I thought it might be useful to show some simple examples on how to get some of that information, for those unfamiliar with the mysqlbinlog tool.

For this example, I used the MySQL benchmark tools to populate data.

You can review binary log events a couple if different ways.
You can use the command line :

      mysqlbinlog mysql56rc-bin.000010
or within MySQL via a simple query.
      SHOW BINLOG EVENTS IN 'mysql56rc-bin.000010' ;

These will both dump out all of the data, and this demo currently has 2284725 rows of data, to much to review …

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L2 cache for MySQL

The idea to use SSD/Flash as a cache is not new, and there are different solutions for this, both OpenSource like L2ARC for ZFS and Flashcache from Facebook, and proprietary, like directCache from Fusion-io.
They all however have some limitations, that’s why I am considering to have L2 cache on a database level, as an extension to InnoDB buffer pool.
Fortunately, there is a project in progress Flash_Cache_For_InnoDB by David which implements this.
David helped us to port his work to the latest Percona Server and you can get it from our launchpad Percona Server 5.5.28

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MySQL 5.6.7-RC in tpcc-mysql benchmark

MySQL 5.6.7 RC is there, so I decided to test how it performs in tpcc-mysql workload from both performance and stability standpoints.
I can’t say that my experience was totally flawless, I bumped into two bugs:

But at the end, is not this why RC for? And Oracle asked for a feedback, so I do my part.

  • Benchmark date: Oct-2012
  • Benchmark goal: Test how MySQL 5.6.7 performs
  • Hardware specification
    • Server: Dell PowerEdge R710
    • CPU: 2x Intel(R) Xeon(R) CPU E5-2660 0 @ 2.20GHz
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A (prototype) lower impact slow query log

Yesterday, over at my personal blog, I blogged about the impact of the MySQL slow query log. Since we’re working on Percona Server 5.6, I did wonder if this was a good opportunity to re-examine how we could provide slow query log type functionality to our users.

The slow query log code inside the MySQL server does several things that aren’t good for concurrency on modern systems. For starters, it takes a mutex while both doing formatting of what to write and while doing the write(2) system call itself. This is, in fact, entirely unneccesary.

From the man page for the write system call:

If the file was open(2)ed with O_APPEND, the file offset is first set to the end of the file before writing. The adjustment of the file offset and the write operation are performed as an atomic step.

So we can …

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Record performance with PCIe Micron RealSSD™ P320h

I have a chance to test Micron RealSSD™ P320h. Initially I was expecting a good performance, but you know, how big could be a difference with other products on market? PCIe SSD market is getting crowded, and every company is trying to show the best performance. And at the end, there is a single PCIe slot, single controller, we are probably about to reach limits of these components.
However I was really surprised to see performance numbers with Micron P320h.
In random reads the throughput is 3200 MiB/sec, while the best results I’ve seen so far was 1450 MiB/sec on single card and 2300 MiB/sec on duo.

And this is 16KiB blocksize, which gives us 200.000 random reads IOP/sec, again in 16K blocks (not 512 or 4096 usually used in public benchmarks).

The write random …

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Intel SSD 910 vs HDD RAID in tpcc-mysql benchmark

I continue my benchmarks of Intel SSD 910, previous time I compared it with Fusion-io ioDrive http://www.mysqlperformanceblog.com/2012/09/07/intel-ssd-910-in-tpcc-mysql-benchmark/. Now I want to test this card against RAID over spinning disks.

Benchmark date: Sep-2012 Benchmark goal: Test Intel SSD 910 under tpcc-mysql workload and compare with HDD RAID10 Hardware specification
  • Server: Dell PowerEdge R710
  • CPU: 2x Intel(R) Xeon(R) CPU E5-2660 0 @ 2.20GHz
  • Memory: 192GB
  • Storage: Hardware RAID10 over 8 disks, card: Perc H710, disks: Seagate ST9750420AS 750GB, 2.5″, 7200RPM, 16MB, SATA. Intel SSD 910 (software RAID over 2x200GB devices)
  • Filesystem: ext4
Software
  • OS: Ubuntu 12.04.1
  • MySQL Version: Percona Server 5.5.27-28.1
Benchmark …[Read more]
Adaptive flushing in MySQL 5.6 – cont

This is to continue my previous experiments on adaptive flushing in MySQL 5.6.6. Now I am running Ubuntu 12.04, which seems to provide a better throughput than previous system (CentOS 6.3), it also changes the profile of results.

So, as previous I run tpcc-mysql 2500W, against MySQL 5.6.6 with innodb_buffer_pool_size 150GB, and now I vary innodb_buffer_pool_instances as was advised in comments to previous post. I also tried to vary innodb_flushing_avg_loops, but it does not affect results significantly.

So, let’s see throughput with 10 sec averages.

Obviously with innodb_buffer_pool_instances=1 the result is better and more …

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Intel SSD 910 in tpcc-mysql benchmark

I continue my benchmarks of Intel SSD 910, the raw IO results are available in my previous experiment. Now I want to test this card under MySQL workload to see if the card is suitable to use with MySQL.

Benchmark date: Sep-2012 Benchmark goal: Test Intel SSD 910 under tpcc-mysql workload and compare with baseline Fusion-io ioDrive card Hardware specification
  • Server: Dell PowerEdge R710
  • CPU: 2x Intel(R) Xeon(R) CPU E5-2660 0 @ 2.20GHz
  • Memory: 192GB
  • Storage: Fusion-io ioDrive 640GB, Intel SSD 910 (software RAID over 2x200GB devices)
  • Filesystem: ext4
Software
  • OS: Ubuntu 12.04.1
  • MySQL Version: Percona Server 5.5.27-28.1
Benchmark specification
  • Benchmark name: tpcc-mysql
  • Scale factor: 2500W (~250GB of data)
  • Benchmark …
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