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I have been in the Software business for close to 30 years now, and I have 25+ years with SQL-based relational databases. Although I have used Unix even longer than that, I am pretty much an operating system agnostic. Over the years, I have work in many positions, from support engineer to sales engineer and consultant. Anders is a DZone MVB and is not an employee of DZone and has posted 45 posts at DZone. You can read more from them at their website. View Full User Profile

MySQL Cluster Performance Revisited - tcmalloc Kicks Some A**

08.23.2012
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My now long-running series of posts on getting max performance from a very simple MySQL Cluster setup (see details here) is continuing here. As a short intro to what I am trying out here, is to see if I can validate the claim that MySQL Cluster / NDB would be a good replacement for a Key Value Store (KVS) such as MongoDB. I test this in a rather simple single-server environment, but this is for a reason, just not a coincidence: The reason is that RAM is getting inexpensive and servers that can take a lot of RAM are also getting less expensive, which in turns means that the saying that many small servers are more cost-effective that few big ones, might not be as valid as it used to be. Also, I wanted to test what MySQL Cluster can do for me, from a KVS centric view. In short, I run on one server (16 Gb RAM, 8 cores) with all data in memory, what do I get.

I can tell you I have been trying real hard to get MySQL Cluster to work better here. Yes, SQL parsing in MySQL is to blame for a lot of why MySQL Cluster is so much slower than MongoDB. But why is MySQL Cluster slower than a fully cached (hot) InnoDB then? Admittedly, I was running the InnoDB tests with MySQL 5.6, so there you have one more thing for me to try (i.e. running InnoDB tests with the mysqld packaged with MySQL Cluster).

A lot of different MySQL Configurations was tried, as was a few other things. Lookiing at what was going on in the box revealed that most of the CPU was consumed by mysqld, so I decided to try to speed that up a bit, as the CPUs were maxed out by mysqld using up some 85 % or so. Using tcmalloc seemed like one obvious fix here, and I got some 10% better performance using that, MySQL Cluster using the SQL interface now performance about 35 k requests per second, which still is below InnoDB (with MySQL 5.6) and not even close to MongoDB, but still an improvement.

But as I said, there is still more stuff to test and I am not giving up yet. But I have given up on distributing some mysqld load to some other server. I got that working, but as the load on the test is distributed evenly across the mysqld servers, the slowest one will hold things up (that is how thing work right now, but I can and will revisit that one). Tarantool, some more NDBAPI tests and then some remains to be tested!
Published at DZone with permission of Anders Karlsson, author and DZone MVB. (source)

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