Re: The REAL cost of joins

On 4/03/2010 4:47 PM, Richard Huxton wrote:
> On 03/03/10 21:59, Marcin Krol wrote:
>> What do you think of this? And in general: when (if?) should one
>> denormalize data?
>
> As a last resort. No sooner.
>
> The support costs of denormalising your database is such that if you can
> reasonably just buy more hardware / add caching / etc, do so.

Well, materialized views are a denormalization of sorts, and a really
useful one - but they're not the authorative store of the data.

Things like views, materialized views, trigger-maintained side tables
etc are what you should look at before even considering denormalizing
your main data storage.

--
Craig Ringer