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

INSERT data problem!
After having an string with apostrophes ', double quotes " or any other special characters, suc

Validating time
Hi Guys

what do you think of the following approach to validate a 24hour time:

http://

Create or replace package is ending ORA-21700
Database 9.2.0., patch 8 (9.2.0.8.0).
I trying run
create or replace package ....etc.

Mysql query, two times?
Hello to all,

I'm new to php coding and i like it alot. I need help with some noob stuff.

How to add an image/C++ OpenGL?
Hi,

I have been trying to look online for this and, so far, I haven't found anything usef

Text Not Displaying Correctly With PHP:GD
I recently moved servers and since then I have noticed that one line of text is showing weirdly.

Can anyone give me some link on .htaccess tutorial
i wish to have friendly url using .htaccess, but no idea yet about this

Hope that anyone cou

Feed Maker
Hi all.
First of all I must say I am not a php developer so I am afraid I don't know much about i

Multiple Options for a Single Page
For this example I want to use the Handlers option which is under Fed Admin and all the related codi

Google voice
I currently have a form in html, but I want it in php so the information is not in the source code.<