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!

No comments posted yet

Your Answer:

Login to answer
343 Like 48 Dislike
Previous forums Next forums
Other forums

How to use php and sql to check if values match the ones in a table (for logins)
How would I code it that the script takes two variables that are passed to it (UserID and PIN), and

function not returning the correct value
I have a program that needs to return a value from a function. I have an output statement inside the

Remore client postprocessing phase getting dump SAPSQL_ARRAY_INSERT_DUPREC
Hello Expects,I have started remore client copy. Data was copied successfully. but while running pos

Calculating n! using vector
#include
#include
#include

using

What do you call the "token" thing?
You know how some sites have links that run on tokens? Tokens are links that only stay alive for a c

Login logout link help
Hi all,

Im new to php and Im having trouble creating a login/logout link for my page that dis

Problem with Subscreen
Dear Experts ,
I am facing a problem with the subscreens. My senario is as follows :

how do i make a string??
hey guys,
can someone please tell me how to put data from the glob function into a string

Sendmail.php - heading error following check_input
Hi,

I would greatly appreciate some help? I am brand new to PHP and have been searching and e

help with this code please?
Hello,

I am trying to build a remote upload script for my image hosting site.

I am usi

Sign up to write
Sign up now if you have flare of writing..
Login   |   Register
Follow Us
Indyaspeak @ Facebook Indyaspeak @ Twitter Indyaspeak @ Pinterest RSS



Play Free Quiz and Win Cash