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Full Discussion: Honey, I broke awk! (duplicate line removal in 30M line 3.7GB csv file)
Top Forums Shell Programming and Scripting Honey, I broke awk! (duplicate line removal in 30M line 3.7GB csv file) Post 302894660 by Michael Stora on Wednesday 26th of March 2014 03:08:12 PM
Old 03-26-2014
Honey, I broke awk! (duplicate line removal in 30M line 3.7GB csv file)
I have a script that builds a database ~30 million lines, ~3.7 GB .cvs file. After multiple optimzations It takes about 62 min to bring in and parse all the files and used to take 10 min to remove duplicates until I was requested to add another column. I am using the highly optimized awk code:
Code:
awk '!($0 in a) { a[$0]; print }'

In this case a[$0] mearly initializes the array element without writing to it and ($0 in a) aparently accesses an array table but not the elements themselves.

The traditional solution took many hours even with test chunks of the data.

I previously tried to debug some files with corruptions by adding a filename@path column and that exceeded the maximum pipe size. I was asked to add a relatively short column and it does not break any pipes but does not complete even after 12 hours.

I've removed several pipes in my script and replaced them with temp files to hold data between commands, but the addition of that short column has caused the duplicate line removal to go from ~10 minutes to God knows how long.

Any other options to do the duplicate line removal more efficiently (in segments, sorting first, etc.)?

Do I have any other options? My environment is:
GNU Awk 4.0.2
GNU bash, version 4.1.10(4)-release
CYGWIN_NT-6.1-WOW64 1.7.17(0.262/5/3) 2012-10-19 14:39 i686 Cygwin
Windows 7 Enterprise Ver 6.1 Build 7601 Service Pack 1
Last edited by Michael Stora; 03-26-2014 at 05:32 PM..
 

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LEARN ABOUT CENTOS

processcsv.py

PROCESSCSV.PY(1)					      Virtualization Support						  PROCESSCSV.PY(1)

NAME

       processcsv.py - process virt-top CSV files

SUMMARY

	virt-top --csv data.csv
	processcsv.py < data.csv

DESCRIPTION

       virt-top is a top(1)-like utility for showing stats of virtualized domains.

       processcsv.py is a simple Python script that post-processes the output of "virt-top --csv".

       It is used like this:

	virt-top --csv data.csv
	processcsv.py < data.csv

       The second command will overwrite the following files in the current directory:

       "global.csv"
	   This contains the global (host) statistics columns from the CSV file.

       "domainNN.csv" (multiple files)
	   For each libvirt domain ID NN, a file is created containing the per-domain statistics from the CSV file.

SEE ALSO

       virt-top(1)

AUTHORS

       Richard W.M. Jones <rjones @ redhat . com>

COPYRIGHT

       (C) Copyright 2007-2012 Red Hat Inc., Richard W.M. Jones http://libvirt.org/

       This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by
       the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

       This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

       You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation,
       Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

virt-top-1.0.8							    2013-12-29							  PROCESSCSV.PY(1)
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