Best way to cross matching large datasets

Posted on 16th Feb 2014 07:03 pm by admin

Hi,

Im running a script where am I cross matching about 200 000 data sets with each other. Each data set consists of 8 parameters and I want to count all datasets which have similar or the same parameters for each data set.

Right now, I am doing the matching via a MySql query which im calling about 200 000 times. The problem is that using a query is extremely expensive… it takes up to 2 hours until the script is done. So I am wondering if there is a better method to cross match data sets and if some of could help me find a better solution.

While researching I found out that arrays may be a faster alternative to queries. And so far, I identified 3 possible ways for cross matching:

1. nested foreach () loops
foreach($array as ar1)
foreach($array as ar2)
if ($ar1[0] == $ar1[0])….

2. Using an Array_map with Callback function, so that i would have only one "hand coded" loop
foreach($array as arr)
if ($arr[0] == $parameter)….

3. Array walk where i could save one "hand coded" loop as well.

Theoretically would be the best/fastest way to go about it? Can Anyone tell me what technically the difference between those 3 ways is? And which one is the better approach or if there other alternatives to them?

I am thankful for any advice that helps me reduce execution time!

Your Answer:

Login to answer

Other forums

iMatch stored value with the current value in a loop
Hello,

I have a MySQL db were I store articles in.

I have a form to fill these article

How could I do this?
Ive got a simple lottery game, and am using an sql database to keep track of the numbers bought. But

Sharing PHP Sessions Across Domains
I am in the process of writing a script to share a php session across various domains I have.
The

Paypal
Hi all,

I have an advanced basic knowledge of php

I want to try something new for a s

Multi Level Array Problem
hi all,

For example I have array like below:

$temp = array(array('north america', 'us'

array ...
hi
Code: function formatCategories($categories, $parentId)
{
// $navCat stores all child

How to display random record from table?
I have the following code:

Code: <?php
$display_block .= "<input type=

Not sure why this script is not working?
Hi I am new to php programing and I was trying to make up a simple script like a captcha but I canno

PHP5 - AJAX help
I've been following the tutorial on w2schools (http://www.w3schools.com/php/php_ajax_database.asp) a

Clean URLs
Hi I was wandering if anyone has ever implemented URLs on their PHP run website using URLS like wiki