Subject RE: [firebird-support] MAX vs. FIRST 1
Author Rick Debay
There is a bug report in the tracker stating that MAX or MIN takes three
index reads instead of one. FIRST takes only one index read.

-----Original Message-----
[] On Behalf Of PenWin
Sent: Tuesday, July 31, 2007 5:47 AM
Subject: Re: [firebird-support] MAX vs. FIRST 1

> which of the following two statements would be better or is there some

> other statement that I should rather use? There will be in excess of
> 500,000 records per store. It seems to me that the "FIRST 1" would be
> the better one to execute but is it really going to make that much
> difference? I have seen the "SELECT MAX" statement take as long as 16
> minutes when the server is under load, I think that this is due to
> garbage collection. So could I avoid garbage collection by using the
> "FIRST 1"?

Interesting replies to your question. I always thought MAX is faster
because I would have expected the database to simply consult the index
and come out with the largest value, as opposed to first selecting all
matching rows, then sorting them and finally returning the first one.
(Assuming I have an applicable index, obviously)



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