Hello monks,

I have a relatively large datafile (100MB or so). All lines from this file are to be processed and dumped to MySQL table, **except** those lines that are already in MySQL table.

For example, ids F1,FTDR,RJIER,KERF are present in MySQL and I dont want to process lines from the datafile beginning with these IDs. I do the following at this time:

# populate DISTINCT ids from table into a variable
# separated by pipe symbol; variable looks like below
# and contains 15000 distinct ids
$compare = "F1|FTDR|RJIER|KERF...." 

# open the file and loop
open (MFIL,"<datafile") or die ("ouch");
while ($lines = <MFIL>)
{
  chomp ($lines);
  $lines =~ m/^$compare/o && next;
  print $lines,"\n";
}
close (MFIL);

[download]

This takes over 5 minutes on a 384MB RAM box running FC4 kernel 2.6.11 and Perl v.5.8.6.

If I process all lines from the file and handle MySQL errors (of duplicacy) manually, the file takes about 3 minutes. I am sure there should be a better/faster method to doing this. Please feel free to suggestion me options.

Thank you, all.

Regards,
Chirag Shukla

In reply to large file and processing efficiency by chiragshukla

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