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

Remove values in array2 from array1
I have two arrays.

Array 1 is where the array key holds various different numbers. For exampl

HTML form problem
Ive made a form to that i want to send to my email via PHP. but when it send only the name's etc sen

$_POST variable un-useable
I'm trying to use a $_POST variable in a mysql update statement but i can't use it for some unknown

Code working in IE but not FireFox
I created a dynamic navigation list for my website based off of a table in my database. The code is

Multi Level Array Problem
hi all,

For example I have array like below:

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

Production Order Enterprise Service to Manufacturing Exctn Sys (MES) ???
Hello Experts,

In our current landscape SAP ECC 5.0 is integrated to MES system via PI 7.

What's wrong with my code
sobbing for many days, still don't know why please Help. Why my page isn't posted correctly. In a

Linking with Foreign Keys
I have been getting an erro when I try and link:

create table Faculty_Specialty (I_Name v

Stumped by Third Day of Month problem
I am trying to build an algorithm that will essentially do this:
Code: [Select]$this_month = Oct

Not Inserting into DB
I can't get my Add new Division form to submit to the database. Anyone see my issue?

Code: &a