But you calculations are still wrong:
500 kb/s = 62.5 kB/s 62.5 kB/s * 100 users = 6 250 MB/s 6 250 MB/s / 4 kB (4096 B) = 1562.5 queries per second
Well that's too much. At this load 4096 can be increased to 409600, the database load would be only 15.625 queries per second.
Nathan Taylor wrote:
Actually, correct that, 200 queries every 8 seconds! It won't just explode, it will create a mushroom cloud while it's at it!
----- Original Message ----- From: Marek Kilimajer To: Alex Cc: [EMAIL PROTECTED] Sent: Tuesday, September 30, 2003 6:32 AM
Subject: Re: [PHP] download queue
I would do it this way. Output your files and update bandwith usage:
while($out=fread($file, 4096)) {
echo $out;
UPDATE bandwith_usage SET bandwith_usage = bandwith_usage+1 WHERE second = UNIX_TIMESTAMP() LIMIT 1
if(mysql_affected_rows()==0) { // if this is the first output in this second
INSERT bandwith_usage SET bandwith_usage = 1, second = UNIX_TIMESTAMP()
}
}
When you are about to start a download, check the bandwith usage first, in this case for the last minute:
SELECT AVG(bandwith_usage) usage FROM bandwith_usage WHERE second > UNIX_TIMESTAMP() - 60
usage * 4096 gives you usage in bytes per second. If it exceeds your limit, output a html page (sorry...), else open the file and start the above loop.
You might want to change 4096 to a higher value. You should also implement a garbage collector that will remove old bandwith usage data, the collector can make usage statistics too.
Alex wrote:
> I'm considering start up a small download site with the large amount of > excess bandwith I have on my site, however I thought it would be cool to > put some sort of download queue up (you know, so all my bandwith doesn't > get eaten up when 500 random people suddenly decide to download a 500meg > file i've put up.
> > In any case, I'm once again to the point where I know what I want, but > the logic of it escapes me. If anyone has ever done this before, seen > the code behind this before, or knows basically how this would be done, > I'd be more than happy if you would share your wisdom with me.
>
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