Posted by Greg D. Moore \(Strider\) on 04/25/07 14:37

"Nacho" <nacho.jorge@gmail.com> wrote in message
news:1177509485.676313.103910@s33g2000prh.googlegroups.com...
> Hi,
>
> I'm designing a new database and I have a doubt in which surely you
> can help me.
> I'm storing in this database historical data of some measurements and
> the system in constantly growing, new measurements are added every
> day.
> So, I have to set some extra columns in advance, so space is available
> whenever is needed and the client doesn't have to modify the structure
> in SQL server.

Umm... I don't see why you have to do this now.

Do it later.

I mean will you even know the type or size of the columns now?

And how will you even give them meaningful names when they have none now.


> The question is: the more columns I add "just in case", the slower the
> SQL reads the table?
> Of course the "empty" columns are not included in any query until they
> have some valid data inside.
> Will I have better performance if I configure only the columns being
> used at the moment, without any empty columns?

A tad (since there's a small metadate overhead on the leave nodes).

But more importantly, you'll have a messy schema on your hands. I'd wait to
add them.


>
> Thanks in advance.
>
> Ignacio
>



--
Greg Moore
SQL Server DBA Consulting Remote and Onsite available!
Email: sql (at) greenms.com http://www.greenms.com/sqlserver.html

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