Re: [HACKERS] What about LIMIT in SELECT ?

From: Terry Mackintosh <terry(at)terrym(dot)com>
To: Jeff Hoffmann <jeff(at)remapcorp(dot)com>
Cc: PostgreSQL-development <hackers(at)postgreSQL(dot)org>
Subject: Re: [HACKERS] What about LIMIT in SELECT ?
Date: 1998-10-14 17:21:51
Message-ID: Pine.LNX.3.95.981014130857.14397B-100000@terry1.acun.com
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On Tue, 13 Oct 1998, Jeff Hoffmann wrote:

> >Hi, my 2 cents...
> >
> >I agree completely, LIMIT would be VERY usefull in web based apps, which
> >is all I run. It does not matter to me if it is not part of a formal
> >standard. The idea is so common that it is a defacto standard.
>
> i'm not familiar with mysql and using "LIMIT" but wouldn't this same effect
> be achieved by declaring a cursor and fetching however many records in the
> cursor? it's a very noticeable improvement when you only want the first 20
> out of 500 in a 200k record database, at least.

Yes, while this is an improvement, it still has to do the entire query,
would be nice if the query could be terminated after a designated number
of rows where found, thus freeing system resources that are other wise
consumed.
I have seen web users run ridculous querys, like search for the
letter 'a', and it happens to be a substring search, now the box go'es ape
shit for 5 or 10 min.s while it basically gets the whole db as the search
result. All this befor you can do a 'FETCH', as I understand FETCH, I
will need to read up on it.

Note that I do not have any databases that larg on my box, I was thinking
back to my VFP/NT experiances.

Have a great day
Terry Mackintosh <terry(at)terrym(dot)com> http://www.terrym.com
sysadmin/owner Please! No MIME encoded or HTML mail, unless needed.

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