Original article available at https://habrahabr.ru/company/mailru/blog/323870/

I’d like to share with you an article based on my talk at Tarantool Meetup(the video is in Russian, though). It’s a short story of why Mamba, one of the biggest dating websites in the world and the largest one in Russia, started using Tarantool. Why did we decide to busy ourselves with MySQL-to-Tarantool replication?

First, we had to migrate to MySQL 5.7 at some point, but this version didn’t have HandlerSocket that was being actively used on our MySQL 5.6 servers. We even contacted the Percona team — and they confirmed MySQL 5.6 is the last version to have HandlerSocket.

Second, we gave Tarantool a try and were pleased with its performance. We compared it against Memcached as a key-value store and saw the speed double from 0.6 ms to 0.3 ms on the same hardware. In relative terms, Tarantool’s twice as fast as Memcached. In absolute terms, it’s not that cool, but still impressive.

Third, we wanted to keep the whole existing architecture. There’s a MySQL master server and its slaves — we didn’t want to change anything in this structure. Can MySQL 5.6 slaves with HandlerSocket be replaced with something else without having to make significant architectural changes?

We learned that the Mail.Ru Group team has a replicator they created for their own purposes. The idea of replicating data from MySQL to Tarantool belongs to them. We asked the team to share the source code, which they did. We had to rewrite the code, though, since it worked with MySQL 5.1 and Tarantool 1.5, not 1.7. The replicator uses libslave, an open-source solution for reading events from a MySQL master server, and is built statically without any of MySQL’s system libraries. It’s been open-sourcedunder the BSD license, so anyone can use it for free.

Replication constraints