Re: Pizza Example
Date: Mon, 19 Apr 2004 22:06:24 GMT
Message-ID: <A3Ygc.78473$I%5.5263418_at_phobos.telenet-ops.be>
Anthony W. Youngman wrote:
> In message <9Jugc.75998$vO4.5098632_at_phobos.telenet-ops.be>, Jan Hidders
> <jan.hidders_at_REMOVETHIS.pandora.be> writes
>> >> Sure. Retrieving records with an index is also very fast with DBM >> files. But what happens if you have a query with a couple of joins, a >> little aggregation and some subqueries?
>
> Apply a little statistics. How likely is that going to occur with an
> RDBMS, as opposed to a Pick DB. If the stats say it's unlikely to
> happen, then why worry about it?
In my experience, and of many others I've spoken to, the stats say that for certain applications and environments this is true, and for certain applications it is not. It is also my experience that in many cases it is understimated how difficult ultimately the queries will become.
Take for example the Wikipedia database. (I mention it because it is open source and you can inspect the application yourself.) You would expect that the bulk of the queries are simple retrieves of encyclopedia pages and that this should be the most optimized operation. They discovered quite quickly that (1) the queries were actually more complicated than that and (2) if the really difficult queries were not optimized then the performance of the whole system went down the drain. Do you think that Pick would be suitable for such an application? They are now using MySQL.
> That's what I meant about Pick queries being impossible to optimise -
> the statistics say there's no room for improvement, or that any gains by
> optimising the unusual case will be lost by hindering the typical case.
I know that's what you meant, and I still agree with that statement. :-)
- Jan Hidders