Splitting website traffic by percentage - php

Question

I need to split up traffic to multiple sources based on an assigned percentage. I figure I need a log table like this:
Table:
+--------+------+----------------------+
| Source | hits | allocated percentage |
+--------+------+----------------------+
| path1 | 50 | 50 |
| path2 | 40 | 40 |
| path3 | 10 | 10 |
+--------+------+----------------------+
I figure the logic needs to loop through all the paths and calculate the current percentage and then determine which one is furthest from the "allocated percentage" and then update the table hits=hits+1. I'm having trouble with the last compare part.
$overall_hits = $db->getall('Select sum(total_hits) from table');
$source = $db->getall('Select * from table');
foreach($source as $row){
$current_percentage = ($row['total_hits']/$overall_hits)*100;
//how should I compare? what if they are equal?
if($current_percentage < $row['allocated_percentaged'])
{
$chosen_path = $row['source'];
$db->sql("Update table set total_hits=total_hits+1 where source='".$chosen_path."'");
break;
}else{
continue;
}
}
Am I even on the right track here?

Answer 1

Presuming I understand what you're trying to do, you can do all of the logic checks in your SQL.
Using the following data as an example:
CREATE TABLE t (
source TEXT,
hits INT,
percentage INT
);
INSERT INTO t (source, hits, percentage)
VALUES
('path1', 41, 50),
('path2', 27, 40),
('path3', 3, 10)
You can simply run a query against the entire table, to calculate what percentage each of the paths is at:
SELECT
source,
hits,
percentage,
(hits / percentage) * 100
AS current
FROM t
ORDER BY current ASC;
Which will give you the following results
SOURCE HITS PERCENTAGE CURRENT
path1 3 10 30
path2 27 40 67.5
path3 41 50 82
You can then simply add LIMIT 1 to the end of your query, to only obtain 1 result. This will give you the path with the lowest number of hits : allocated ratio.
SOURCE HITS PERCENTAGE CURRENT
path1 3 10 30
You can see it in action on SQLFiddle here.