I need to setup an ID (not sequential numbers, need randomness) for each of these unique records.

Why not have the DB give you the randomness you need? If you give each record a sequential (autoincrement) record number--which guarentees uniqueness--and then have an auxillary table which maps that recno to a random 'tag' of say 6 characters: A-Z.

That would give you 300 million unique 6-char tags which should be sufficient to be going on with. And with a properly indexed table, the lookup should be very quick with any DB worth its disk space. If you ever need to expand further you can add a-z to double that; or move to seven chars which would cater for 8 billion.

The toughest part of this suggestion is generating the recno/tag mapping. Or rather, shuffling the tags once you've generated them which Perl makes easy. Shuffling a 300e6 element array is a memory intensive process even if you use an in-place shuffle. A possible solution to this is to break the problem into 2 parts.

Shuffling two small sets of 3-char stems & suffixes is trivial, and combining them at output time means you require minimal memory (~16MB), and it is very fast. It takes about a minute to produce 20e6 or roughly an hour if you wanted the full 300e6:

#! perl -slw
use strict;
use List::Util qw[ shuffle ];


our $N ||= 20e6;

my @tagStems = shuffle 'AAA' .. 'ZZZ';

my $serial = 0;
while( my $stem = pop @tagStems ) {
    for my $suffix ( shuffle 'AAA' .. 'ZZZ' ) {
        printf "%07d\t%s\n", ++$serial, $stem . $suffix;
        exit if $serial > $N;
    };
}


__END__
C:\test>786833
0000001 HBDKCE
0000002 HBDBWB
0000003 HBDRRX
0000004 HBDUJF
0000005 HBDFRH
0000006 HBDMFO
0000007 HBDAEO
0000008 HBDEYC
0000009 HBDCCZ
0000010 HBDXPK
...
0017572 HBDIWS
0017573 HBDQFL
0017574 HBDHYU
0017575 HBDUUL
0017576 HBDCGM
0017577 ZPSQVM
0017578 ZPSOUH
0017579 ZPSPJV
0017580 ZPSGAS
...
[download]

Whilst not truly random--there are some possible sequences that cannot be generated--it is sufficiently random (ie. unguessable) for many purposes.

If you needed to move to 8 billion/7-char tags, using a 4-3 or 5-2 split works equally well.