Earlier on in benchmarking MySQL and MariaDB on POWER8, we noticed that on write workloads (or read workloads involving a lot of IO) we were spending a bunch of time computing InnoDB page checksums. This is a relatively well known MySQL problem and has existed for many years and Percona even added innodb_fast_checksum to Percona Server to help alleviate the problem.

In MySQL 5.6, we got the ability to use CRC32 checksums, which are great in that they’re a lot faster to compute than tho old InnoDB “new” checksum. There’s code inside InnoDB to use the x86 SSE2 crc32q instruction to accelerate performing the checksum on compatible x86 CPUs …

IBM POWER 8 is latest generation of the IBM POWER series, and it's a hot one. Above all, for you reading this, POWER 8 is the most Linux friendly so far and IBM really wants you to try this out. Seveal Linux distributions are supporting POWER 8 now, and MariaDB is of course the database of choise. Some cools things with the POWER 8 architecture are the support for CAPI (google for more details) and the fact that POWER 8 machines, due to a vastly superior memory architecture, can grow in memory size, which in general is good news but if you want your own POWER 8, this makes then a bit expensive (although maybe not when you consider the performance you get). IBM has fixed that recently and have announced the LC series of servers which start at $6.600 (see more here: http://www-03.ibm.com/systems/power/hardware/linux-lc.html).

So, whar about MariaDB …

A couple of days ago, MariaDB announced that MariaDB 10.1 is stable GA – around 19 months since the GA of MariaDB 10.0. With MariaDB 10.1 comes some important scalabiity improvements, especially for POWER8 systems. On POWER, we’re a bit unique in that we’re on the higher end of CPUs, have many cores, and up to 8 threads per core (selectable at runtime: 1, 2, 4 or 8/core) – so a dual socket system can easily be a 160 thread machine.

Recently, we (being IBM) announced availability of a couple of new POWER8 machines – machines designed for Linux and cloud environments. They are very much OpenPower machines, and more info is available here: …

MariaDB 10.1 not only contains tons of new features, it has also been polished to deliver top performance. The biggest improvement has been achieved for scalability on massively multithreaded hardware.

The following numbers show the throughput for a simplified sysbench OLTP benchmark on MariaDB-10.1.8 compared to MariaDB-10.0.21:

At Percona Live MySQL Conference 2015 next week I’ll be presenting on “Towards One MILLION queries per second” on 14th April at 4:50pm in Ballroom A.

This is the story of work I’ve been doing to get MySQL executing ONE MILLION SQL queries per second. It involves tales of MySQL, tales of the POWER8 Processor and a general amount of fun in extracting huge amounts of performance.

As I speak, I’m working on some even more impressive benchmark results! New hardware, new MySQL versions and really breaking news on MySQL scalability.

In C (and C++) you can specify that a variable should take a specific number of bits of storage by doing “uint32_t foo:4;” rather than just “uint32_t foo”. In this example, the former uses 4 bits while the latter uses 32bits. This can be useful to pack many bit fields together.

Or, that’s what they’d like you to think.

In reality, the C spec allows the compiler to do just about anything it wants with these bitfields – which usually means it’s something you didn’t expect.

For a start, in a struct -e.g. “struct foo { uint32_t foo:4; uint32_t blah; uint32_t blergh:20; }” the compiler could go and combine foo and blergh into a single uint32_t and place it somewhere… or it could not. In this case, sizeof(struct foo) isn’t defined and may vary based on compiler, platform, compiler version, phases of the moon or if you’ve washed your hands recently.

Where …

Yesterday, I got the basics going for MySQL Cluster on POWER. Today, I finished up a couple more patches to improve performance and ran some benchmarks.

This is on a 3.7Ghz POWER8 machine with non-balanced memory (only 2 of the 4 NUMA nodes have memory, so we have less total memory bandwidth than we could have, plus I’m going to bind ndbmtd to the CPUs in these NUMA nodes)

With a setup of a single replica and two data nodes on the one machine (each bound to a specific NUMA node), running the flexAsync benchmark on MySQL Cluster 7.3.7, I could get around:

• 3.2 million reads/sec
• 2.6 million deletes/sec
• 2.4 million updates/sec
• 2.4 million inserts/sec.

So, that’s at least in the right ballpark for a first go.

(I’m running this on a big endian host …

So, I’ve written previously on MySQL on POWER, and today is a quick bit of news about MySQL Cluster on POWER – specifically MySQL Cluster 7.3.7.

I ran into three main issues in getting some flexAsync benchmark results. One of them was the fact that I wanted to do this in the middle of all the POWER8 machines I usually use moving buildings (hard to run benchmarks when computers are packed up in boxes on a truck).

The next issue was that ndbmtd (the multi-threaded data node) needs memory barriers for the magic message passing stuff between threads. So, that’s pretty easy (about an eight line patch).

The next issue was in the results from flexAsync, it turns out 32bit math is a bad idea with results from my POWER8 box.

My preliminary performance numbers are fairly promising (actually… what is the world record for a single machine and NDB these days? Single data node?). I think there’s a bit more low …

MariaDB 10.0.14 was recently released, and is available for download here:

https://downloads.mariadb.org/mariadb/10.0.14/

This is the fifth GA release of MariaDB 10.0, and 15th overall release of MariaDB 10.0.

This is primarily a bug-fix release. (MariaDB 10.0 is the current stable series of MariaDB. It is an evolution of the MariaDB 5.5 with several entirely new features not found anywhere else and with backported and reimplemented features from MySQL 5.6.)

Here are the main items of note:

1. TokuDB upgraded to 7.5.0
2. XtraDB upgraded to 5.6.20-68.0
3. InnoDB upgraded to 5.6.20
4. …

Recently, Morgan has been writing on deprecating some MySQL features and inspired by that while working on MySQL on POWER, I wondered “What is the impact of the MySQL query cache on modern hardware?”

We’ve known for over six years (since before we started Drizzle) that the query cache hurt performance. It was for that reason that the query cache was one of the early things to be removed from Drizzle, it just didn’t scale on multi core systems that  we were targeting.

So what about modern hardware? While working on MySQL 5.6 on POWER8, I enabled the query cache and ran a benchmark. …