Help with Crons

[seany123]

Is it possible to Increase a Number by a certain percent Using Crons example...

 

Maxenergy = 100.

 

20% of maxenergy = 20.

 

so cron updates value by 20.

[cooldude832]

what??

 

CRON is the aility to execute a script  at a certain time

[seany123]

okay is it possible to create a Script which will do this?

[cooldude832]

increment what a field in a database?

[DarkWater]

In a database? >_>

[seany123]

yes sorry a value in a database....

 

has to work out 20% of $maxenergy... and give it to $energy.

 

---------------------------------------------------------------------------

 

to help people understand what i mean... im building a game with php....

 

i have a energy bar which i need going up 20% every 5 minutes.

 

$maxenergy = 100 (but can change)

 

now i could just :

 

$energyupdate = $player->energy + 5;

$query = $db->execute("update `players` set `energy`=? where `id`=? and `energy`<`maxenergy`",

array($energyupdate, $player->id));

 

 

but because maxenergy can change +5 would be unfair on alot of players... so i want it to gain 20% of maxenergy instead.

 

 

[DarkWater]

Cron:

*/5 * * * * /usr/bin/php -f yourscript.php

[seany123]

its a script that im looking for help with.

[BlueSkyIS]

so you need to know how to increase a value by 20%????

 

$energyupdate = $player->energy * 1.2;

[DarkWater]

<?php
$query = "SELECT * FROM players";
$result = mysql_query($query) OR die(mysql_error());
while ($row = mysql_fetch_assoc($result)) {
  $energy = $row['energy'] + ($row['maxenergy'] * .20);
  $energy = ($energy > $row['maxenergy']) ? $row['maxenergy'] : $energy;
  $query = sprintf('UPDATE players SET energy = %d WHERE id = %d', $energy, $row['id']);
  mysql_query($query) or die(mysql_error());
}
?>

 

Math skills really come in handy for programming. =/

[seany123]

So the code you now said will check what the $Maxenergy is... then give 20% of $maxenergy to $energy?

[DarkWater]

Yeah.

[seany123]

okay ill test it out and see what happens thankyou.

[cooldude832]

At Darkwater that is disgustingly bloated

 

You can write your query to do update all rows

Update `players` SET energy = (energy+(maxenergy*.2))

 

Now if you don't have a way to set a max value to energy  (so E is not greater than Emax)you need to add a conditional statement

'but don't do a loop to run 5000 queries run just 1 with a condition part please

[DarkWater]

You need to make sure it's not greater than the maxenergy.  Otherwise I would have done it in one query...

[seany123]

you both got me confused lol

 

i cant even test it untill i get mywebsite working again.

[cooldude832]

You need to make sure it's not greater than the maxenergy.  Otherwise I would have done it in one query...

 

Like I said I believe you can set a MAX value for a field to take (and if greater it automatically sets to be what ever MAX is)

 

However you can do conditional like this (untested but can be debugged very easily)

 

UPDATE
`players`
if((energy+(maxenergy*.2) <= maxenergy),
	energy = energy+(maxenergy*.2),
	energy = maxenergy
)

[DarkWater]

Yeah, I know cooldude, but it doesn't really matter for something like this, considering that it'll be run via cron and it'll only take like, 0.3 seconds to run anyway.

[cooldude832]

Yeah, I know cooldude, but it doesn't really matter for something like this, considering that it'll be run via cron and it'll take like, 0.3 seconds to run anyway.

 

 

When u can run 1 query instead of 1 query for each user (which in this forum would  be near 69 thousand)  I think you rather run 1 query.

 

 

69 thousand queries * 4 times an hour * 24 hours a day = 3.312 million queries a day

 

1 query * 4 times an hour * 24 hours a day = 96 queries a day

 

I leave you to make your own predictions

[DarkWater]

MySQL still has to process the data and do multiplications and conditionals (which may be slower in MySQL, I don't use them that often so I don't know) for every single row, so your comparisons are not true at all.

[cooldude832]

Less queries that are written properly  are always better. 

 

A query that doesn't have a WHERE statement means the table needs  not be seeked each time (as you are doing 69k seeks)

 

The simple math being executed is a simple check and takes aggregate time to run (even at running it twice)  + because I have no conditional limiter to my query the given table is only seeked (and updated) in a single pass.

 

You can run test but I have a strong feeling I win in this scenerio

[DarkWater]

Yeah, but I think the result will be negligible, and he's using cron anyway, so a user doesn't need to sit there waiting...

[DarkWater]

I just ran a test, and mine took about 21 seconds to run with 70000 rows.  I didn't try yours because it throws a syntax error I think and I don't feel like cleaning it up.  70000 rows is quite a lot of rows though, and if he was using cron I can't see the issue.  If you clean up your query I'll try testing it too.

[seany123]

maybe i could get you two intelligent people to look on this problem instead...

 

http://www.phpfreaks.com/forums/index.php/topic,215492.0.html

[cooldude832]

well cron still is using processing on your server and if the script is using processing power (or mysql bandwidth) that is bandwidth and processing power that can't be used elsewhere.

 

Sure a user isn't sitting their watching the cron run but you could be bogging down (or crashing your server) because of the cron job