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

Help With editting and deleting form
Hallo !!

So look at this image :

http://img194.imageshack.us/img194/8272/snapshot5f.pn

filesize() returns 0
I have a socket program that runs in an infinite loop, listening for connections, in this socket I h

CURL XML Request [From C to PHP]
Hi,

I need some help converting this into something that will work with PHP.

Code: #

problem in pagination when processing with selectbox form
Hi,

I have a search form, with select boxes, if am selecting the value from the form, it work

Not capturing all the information we require in the form.......
Hi Guys,

I was wondering if you would share some more of your knowledge today, I'm hoping it

update post issues
I am trying to create an update to a post function, while the update does occur, the page routing an

Deleting Partners on the Customer Master.
Does SAP handle removing the Partner from Open Sales Orders when a Partner is deleted in the Custome

trim function issues
Hi guys, total noob here...

So I've been tinkering around with a html and am using php to em

Upload file and add HTML
Hey everyone,

I have a client has meeting agendas and minutes that should be posted online. I

writing my own sobel filter convolution - something is wrong
I am trying to keep it very simple, I cant see anything wrong with my logic, could anybody help poin