I recently was asked how many fsync / sec ( and therefore durable transactions / sec) we can get on FusionIO card. It should be easy to test, let's take sysbench fileio benchmark and run, the next command should make it: ./sysbench --test=fileio --file-num=1 --file-total-size=50G --file-fsync-all=on --file-test-mode=seqrewr --max-time=100 --file-block-size=4096 --max-requests=0 run PLAIN TEXT CODE: Operations performed:  0 Read, 922938 [...]

I recently was asked what maximal amount transactions per second we can get using MySQL and XtraDB / InnoDB storage engine if we have high-end server. Good questions, though not easy to answer, as it depends on: - durability setting ( innodb_flush_log_at_trx_commit = 0 or 1 ) ? - do we use binary logs ( [...]

Oracle recently announcent MySQL-5.5.2-m2 milestone, and I have a predition that MySQL-5.5 will be announced as GA on MySQL UC 2010 in April. So let's make quick on scalability characteristics we should expect from new release. I made sysbench oltp benchmarks on 10 mln rows (worth 2.5GB of data), on our Dell R900 system ( 16 cores, [...]

I have not caused a fist fight in a while, so it's time to take off the gloves. I claim that somewhere around of 99% of advice about tuning MySQL's key cache hit ratio is wrong, even when you hear it from experts. There are two major problems with the key buffer hit [...]

Running many benchmarks on fast storage (FusionIO, SSDs) and multi-cores CPUs system I constantly face two contention problems. So I suspect it's going to be next biggest issues to make InnoDB scaling on high-end system. This is also reason why in benchmarks I posted previously CPU usage is only about 50%, leaving other 50% in idle state. [...]

As I wrote about 2 years ago the feature of Innodb to store copy of master's position in Slave's Innodb tablespace got broken. There is a lot of discussions at the corresponding bug report while outcome of the fix remained uncertain for me (the bug is market duplicate while the bugs it [...]

Question what is better isolation level is poping up again and again. Recently it was discussed in InnoDB : Any real performance improvement when using READ COMMITED isolation level ? and in Repeatable read versus read committed for InnoDB . Serge in his post explains why READ COMMITED is better for TPCC load, so why [...]

I'm running in this misconception second time in a week or so, so it is time to blog about it. How blobs are stored in Innodb ? This depends on 3 factors. Blob size; Full row size and Innodb row format. But before we look into how BLOBs [...]

Our patches for 5.0 have attracted significant interest.  You can read about SecondLife's experience here, as well as what Flickr had to say on their blog.  The main improvements come in both performance gains and improvements to diagnostics (such as the improvements to the slow log output, and INDEX_STATISTICS). Despite having many requests to port [...]

We have been using tpcc-mysql benchmark for long time, and there many results published in our blog, but that's just single workload. That's why we are looking into different benchmarks, and one of them is TPCE. Yasufumi made some efforts to make TPCE working with MySQL, and we are making it available for public consideration. You [...]

I've seen my posts on Ontime Air traffic and Star Schema Benchmark got a lot of interest (links: http://www.mysqlperformanceblog.com/2010/01/07/star-schema-bechmark-infobright-infinidb-and-luciddb/ http://www.mysqlperformanceblog.com/2009/10/02/analyzing-air-traffic-performance-with-infobright-and-monetdb/ http://www.mysqlperformanceblog.com/2009/10/26/air-traffic-queries-in-luciddb/ http://www.mysqlperformanceblog.com/2009/11/02/air-traffic-queries-in-infinidb-early-alpha/ ). However benchmarks by itself did not cover all cases I would want, so I was thinking about better scenario. The biggest problem is to get real big enough dataset, and I thank to Bradley C. Kuszmaul, he pointed me [...]

Percona is hiring. As part of our growth process, we introduced the role of the Shift Support Captain in 2009 (see the original announcement here) to provide customers with a 24x7 technical contact person. The Shift Support Team dispatches incoming emergencies, assigns new issues, handles or escalates incoming Nagios alerts from some customers, and in general makes sure [...]

February and March as busy months for Community events.  There's MySQL University, Fosdem, the Seattle MySQL Meetup & Confoo.ca. Here are the details: February 4th - I'll be presenting a talk via MySQL University on Optimizing Queries with Explain.  This talk will be about learning to read the output from MySQL's EXPLAIN command, and optimizing some [...]

A while back Friendfeed posted a blog post explaining how they changed from storing data in MySQL columns to serializing data and just storing it inside TEXT/BLOB columns. It seems that since then, the technique has gotten more popular with Ruby gems now around to do this for you automatically. So when is it a [...]

We recently released XtraDB-9, and while we did not highlight it in announcement, the release-making feature is ability to save and restore InnoDB buffer pool. The idea is not new and was originally developed by Jeremy Cole (sorry, I do not have the link on hands) some time ago, and now we implemented it in XtraDB. Why [...]

So you get MySQL or other applications using too much memory on the box or OS behaving funny and using more memory for cache and pushing application to the swap. This causes swapping and causes performance problems. This much is obvious. But how bad is it ? Should you count it same as normal Disk [...]

I appreciate opportunity Jos van Dongen from Tholis Consulting gave me. He granted me access to servers with 8 attached Intel X-25M 80GB MLC cards. The cards attached to 2 Adaptec 5805 raid controllers, with 4 cards per controller. The cost of setup is 8 x 260$ (X-25M) + 2x500$ (Adaptec 5805) = ~3000$. Available space [...]

I generally thought about MySQL replication as being quite low overhead on Master, depending on number of Slaves. What kind of load extra Slave causes ? Well it just gets a copy of binary log streamed to it. All slaves typically get few last events in binary log so it is in cash. [...]

After a nice long vacation, it's time to unveil our destinations for public classes in 2010.  We are now offering a course for Developers as well as DBAs.  The dates are: Seattle 16 February San Francisco 18-19 February Boston 22-23 February New York City 25-26 February Montréal 8-9 March Denver 15-16 March Chicago 18-19 March Washington DC 25-26 March Los Angeles 19-20 April Raleigh 22-23 [...]

Dear Community, As of today Release 9 of XtraDB storage engine is available. The release includes following new features: The release is base on 1.0.6 version of InnoDB plugin. MySQL 5.1.42 as a base release Separate purge thread and LRU dump is implemented (this feature was actually added in Release 8, but somehow it was forgotten) New patch innodb_relax_table_creation Added extended statistics [...]