On Mon, Nov 10, 2008 at 9:47 AM,  <[EMAIL PROTECTED]> wrote:
>
>> But joins are what relation databases excel at, so PHP would be the
>> bottleneck in your example.
>
> Not always...
>
> If your JOIN can not be easily constrained in the query, until some kind of 
> processing of the result set takes place, you can end up with a monster 
> interim result set that will swap the DB server, and send it to its knees.
>
> For example, if you need a result set of 10 items, some of which (but not 
> all) relate to a second table, and the left outer join the generates millions 
> of rows...
>
> Also:
>
> SQL is great at many things.
>
> But something like a tree traversal or other results that depend on the rows 
> returned can be a real bear, especially for pages that are not your core 
> scalable must-have part of the site -- Where you don't want to complicate 
> everything else for just this one admin/report page.
>
> I'm only saying that, on occasion, the dozen DB calls wins out over a JOIN 
> that swaps madly.

I'm not saying such situations don't exist, but in my experience they
are pretty rare -- especially since MySQL added support for
subselects.

Andrew

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