How big is the team over at pinterest managing the MySQL infrastructure? I think this is the big difference here.
I have a particular project. The database has well over 1 billion rows in multiple tables which need joins to generate complex reporting.
As the only tech here, there is only so much I can be working on. Before... time spent on trying to get MySQL to work, was time not well spent. I spent countless hours on IRC talking to devs on #mysql/#mariadb and was told many times, you seem to have the indexes in the right places and the query was well written, you are lucky you are getting it that fast.
Sure, if I had a huge team like Instgram (who I think sharded mysql) and Pinterest. I could assign dbas to get my MySQL infrastructure to scale and possibly fork my application to work different.
I even called Percona and Mariadb and was given pricing from $50 to $70k to work the issue. Note, that they didn't even promise to resolve it. They needed between $10 to $20k up front to check my schema and the data and then the other sum to do the work. Really, almost $100k and no concrete answer?
So I don't have a team and I didn't employ Percona/Mariadb to help solve my issue. Instead, I did something completely different. Some may even say drastic.
I need something simple, that will work with the 5x9's and is very robust. So instead, I went to Postgres. I ran to Postgres. I ran and didn't look back.
With Postgres, 80% of my issues went away. PG 9.5 has some features that ALL of my issues will go away and I may be able to have quarterly queries of 10b rows with multiple tables in under 2 seconds. Cloudflare is currently doing it and I'm trying to replicate it.
Bottom line is this. MySQL for me, was a dead end. Postgres seems to every year go from strength to strength.
Postgres isn't shiny. It's dependable, actually cares what you are putting in the database. Makes your schema simple because you can go from var(x)/int(x) to text/int and it's still fast.
I've converted about 10 other dbas who were used to MySQL and thought PG was hard, to switch over. Now, like me. They won't look back.
If you are still using MySQL. Take a look at Postgres. MySQL has lost it's shine. It's now dull.
Fingers crossed PG 9.6 comes with MPP capability. That would really blow the doors off!