If I'm reading right, you're doing a linear search through the text file each time looking for a specific $userid.

If the file is sorted, and you're looking for values in the same order, then you can use seek and tell to move around in the file. Something like this: 

my $last_pos = 0;               # start at the beginning
# later....
seek(FILE, $last_pos);          # go to where I was
while (<FILE>) {                # start reading line at a time
     if (/$userid/) {           # sure about the /o, BTW?
        $last_pos = tell(FILE); # remember this spot
        ....                    # other stuff

[download]
You can see why order is important: I'm assuming you can find the next record by advancing in the file.

If the requests are in random order, then it may be worthwhile to build your own index (we used to call these ISAM files back in the day ;-). In the beginning of your code, scan the file once, build a hash of positions. Then you can seek to any particular record. Something like this: 

my %index;
while (<FILE>) {
    $userid = split(...)     # It's in there somewhere, right?
    $index{$userid} = tell(FILE};
}
# later...
seek(FILE, $index{$userid});
$_ = <FILE>;
($inv, $date, $amt) = split (...);

[download]
You'll have to fiddle with these to make sure you're seeking to the right spot in the file

Now the big suggestion: forget everything I just wrote! Get yourself a relational database and get rid of all this seek/tell stuff. If you've got that much data and you're doing random reads, there's just no point in writing your own ISAM stuff.

HTH

In reply to Re: Search Efficiency by VSarkiss
in thread Search Efficiency by treebeard

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