Seriously, WTF?

Dirk Koopman djk at tobit.co.uk
Thu May 8 13:40:01 BST 2008


Steve Sims wrote:
>> MySQL 5.1 is great product and I'm quite certain these days you
>> wouldn't run into the problems you've talked about.
> 
> I *did* test out with MySQL 5 (which I believe was still beta), and this was
> executing the queries in question in 6s, but suffered from exactly the same
> scaling issues.  So if I deployed it I would still have had the same
> problems.  I needed a solution there and then...

The real issue with MySQL scalability is to do with which backend engine 
one uses. If you were using 3.1 then you were using MySQL native isam 
tables (there being no choice at the time) - these are OK *provided* you 
have enough RAM to hold the whole index in memory. With eight tables + 
indexes, I don't imagine this requirement held. Hence the crappy 
performance.

This limitation is, IMHO, one of the reasons behind MySQL going 
multi-backend. In effect you now have (at least) three storage engines, 
each with a common front end. Each of these engines have completely 
different scalability / speed characteristics and tradeoffs.

Dirk


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