Perl script to do a fast nextval() calls in PostgreSQL to show the cache = 1 vs. cache = 10000 and speed differences. Note: Lots of "sql injection" happening here because this is a demo. This runs so fast that the prepare time (when using proper ? syntax) was actually much more CPU than the work itself.

pg.pl

#!/usr/bin/perl

use strict;
use DBI;
use Parallel::ForkManager;

# seqtest=# create sequence t1 increment by 1 start with 1 cache 1;
# CREATE SEQUENCE
# seqtest=# create sequence t1000 increment by 1 start with 1 cache 10000;
# CREATE SEQUENCE

my $seq = shift or die "Please provide sequence name as arg #1\n";

my $dbh = DBI->connect("DBI:Pg:dbname=seqtest", "", "", { RaiseError => 1 }) or die("Could not connec to db\n");

my $pm = Parallel::ForkManager->new(10);

for ( my $i = 0; $i < 100; $i++ )
{
    my $pid = $pm->start and next;

    # now am child
    my $d = $dbh->clone;

    for( 1..10000 )
    {
        # $d->do("select nextval(?)", undef, $seq);
        $d->do("select nextval('$seq')");
    }

    $pm->finish;
}

# we are purely parent at this point
$pm->wait_all_children;
warn("done!\n");

1;
__END__