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

mysql query with single quotes in a variable
$sitedetails = "INSERT INTO vars (address, sitename, description, ownername, theme) VALUES ('$u

help with image upload code
Hello,

right now this code I have resizes images and then places them into the uploads folder

Email with Attachments in PHP
Hi Friends

How to send email in PHP with attachment.
I know simple mail can be sent with

gather checkbox data from form into email
Hello all,

First, i'd like to thank everyone who responded to my previous posts regarding set

Oracle Connectivity
Hi Every One,

Can we access SAP from oracle database.If it possible then please spec

Alternate messaging
I have 4 strings in MySQL db1

$string1 : Hello
$string2 : Hi
$string3 : Great
$strin

Show message after entering data
Hello Colleagues

I would like to display messages after entering the data example: "
dat

Image loading
Hi Developers,

I'm trying to display an image from images/image.gif getting the url from mysq

apart from cron
I need to run a php file every one hour. Is there any other solution apart from cron job?

Code Review - SQL and Insertion Attacks (Warning: Not for Newbs)
Hey guys,

Its been a while, I know. Use to love coming here to answer peoples questions, but