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Comment by catch23 | Hacker News Reader

I'm not sure why they chose MySQL. Does mysql still scale linearly up to 8 cores? I figured most people who need 8 cores for mysql would have already gone to sharding or partitioning.

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I think it has more to do with user demand, familiarity, and also the ability to migrate over, as many users already use MySQL.

5.1 scales better, and I would bet they're looking into XtraDB (if not already using it) which will go even further on multi-core machines.

edit - 5.1 (recent releases) scales better mostly due to InnoDB 1.0.4 which incorporates a number of patches from Google (Mark Callagan), Percona and more.

but still, it doesn't scale as linearly as other databases like Oracle or PostgreSQL. Even compared against MySQL 5.1, PostgreSQL scales linearly all the way up to 128 cores -- so it seems like for big databases, you'd want to use something that can actually utilize all 128 cores.

I'm pretty sure they're using MySQL because it's popular, not because it scales. I figure when people hit 10 million rows in a MySQL table, they start looking at sharding/partitioning instead of buying a bigger machine.

MySQL scales for reads pretty well since it has a well understood and mature replication system. In contrast, the PostgreSQL replication landscape is somewhat muddy. Scaling writes is a challenge of course, and PostgreSQL might be the better choice there for getting the most out of big hardware. Scaling up can really cost though, as the price-to-performance ratio gets outside of the sweet spot when the hardware you're buying gets more exotic.

I'm not debating which database scales better. I'm questioning why anyone would use a "big" server for mysql. If you're going to do replication with mysql, you don't need 10 servers with 68 gigs of memory -- you'd probably be better off with 100 servers with 4 gigs of memory.

However, if you're going to go with "big" database servers, one should use Oracle or PostgreSQL since they can actually make use of the memory & cpu cores.

Any 64-bit MySQL will do fine with big memory. It is with > 16 cores that modern MySQL suffers from concurrency problems with mutex contention. These AMZN big memory instances have 4/8 cores, well within the area where MySQL performs well.

Is 10 million rows really the number? I have log files on my disk that are much bigger than that, and I manage them fine with "grep". Inside a database, I would consider this amount of data "trivial".

The price is right and their customers use it frequently. They were probably asked about MySQL a ton of times.

They can give MySQL away for free

That's why - http://www.google.com/trends?q=MySQL,+PostgreSQL

More people are googling the word MySQL means it scales better?

It means it sells better.

Does it sell better after all the "I tried Amazon's MySQL and its lack of $FEATURE killed my business" blog posts?

Sure, because if ones business really depends of a some particular feature and cannot survive otherwise, one probably should quit IT and try to choice different field.

Can't argue with you there :)

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