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

Something like an INI editor or a DelimitedText-Editor
Hi all,

Am very, very, very new to PHP and not sure if I should be posting this to a Javascri

Operating System
How in PHP or other language can I detect Operating system, ie Windows XP Home, Windows 7 Ultimate,

Delete Client 066 Earlywatch
Hi all,

in former times client earlywatch was required for SAPs remote access to SAP inst

Using CSS to format MySQL query
Hi,

If i want to have a news page on my site, which displays all records of a table in descen

Solution to the FindControl problem
I have seen may posts about having problems with the FindControl method. Most seem to come about bec

Little problem with form insertion in MySQL, Please help!!!
Hi!,

I'm a little bit new with php and I have a little issue here. I created a webform to ins

Tracking Unique Clicks
Hi guys and gals,

Basically I have a database which tracks clicks on my outbound links, I do

On page view, minus credit
Hello all, please, I need a little help with this script. I am charging one credit (credits can be p

Javascript using window.location seems to lose state
Not sure what forum so let me know if I'm in the wrong place. I have a main window with a ajax grid

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