what takes the less resources

[*JaH*]

I'm rewriting a whole website...and now I came a cross a little piece that I have to verify if a username already exists or not. The website has got more than 25000 members...what takes less resources:

to just select 'em all in one query or to only select the ones that start with the first letter of the username in question? (e.g. a%)?

Does anyone know how I could test these things? How to find out how much cpu power/memory it uses It's a massive website so it's really important that it uses as less possible

[Redcircle]

$query = 'select username from users where username = "'.$username"';
$result = mysql_query($query);
if(mysql_num_rows($result))
{
echo 'User Exists';
}
else
{
//add user code goes here
}

[*JaH*]

oh yeah...hmm stupid very very ah well, it was late ;) thx mate

but what is the function to show how many milliseconds it takes to parse the script?

[jetthe]

but what is the function to show how many milliseconds it takes to parse the script?

i'm dealing with that the "lame" way as some have told me,
i'm starting the page(or rather the first inclusion file) with:

$starttime = microtime();
(to feeeed it)

the ends by printing:

echo "page generated in ";
echo array_sum(explode(' ', microtime())) - array_sum(explode(' ', $starttime)) . ' seconds';


greets[/code]

[*JaH*]

so it's microtime() thanks alot! For some reason I couldn't find it anywhere on php thanks!

[pootergeist]

you could just make mysql do the hard work and set the username field to UNIQUE - that way, trying to insert a new row fails and you can output an error. Saves having to do any select before the insert = less queries = good.