Which MySQL database engine is better for storing sessions and session data: MyISAM or InnoDB?

Question

Pretty straightforward question.

I use InnoDB for everything else, for a couple of reasons. Is it a performance hit over MyISAM for a 'high-traffic' table?

Transceiver

@Charles, MEMORY is a great choice, because it will be waay faster than anything else. Only issue is that session data won't persist between MySQL restarts. – Money

@Greg: MEMORY = MEMORY :-) – Snakemouth

@Chris, while that is true, MySQL restarts shouldn't occur in production. – Vinyl

You also need to define 'high-traffic'. I've seen a website with over 6000 active sessions in a MyISAM table and not break a sweat. – Kenton

@Charles, Mike -- thank you! I hadn't even considered that. @staticsan: Afraid I can't put a number on it at this time. – Transceiver

@Vinyl Restarts occur pretty much everywhere. How do you deal with configuration changes, and those wonderful times when someone trips over the cord? – Money

@Chris, a fair point. However, at that point the entire site is likely to go down, so losing only session data is likely to be the least of our cares. – Vinyl

Answer 1

Since you're looking at a pretty even mix of read/write traffic, InnoDB is the better choice. MyISAM's full-table locks on every write would probably be murder. MyISAM fairs better with 90%+ read or 90%+ write situations.

I believe that's mentioned in High Performance MySQL

Halfandhalf