CREATE TABLE t (id INTEGER PRIMARY KEY, str TEXT)
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and filled the table with 20_000 random strings. Then I used the following simplistic script to benchmark.

use Cache::Memcached;
my $memd = new Cache::Memcached {'servers' => [ "localhost:11212" ]};

use DBI qw(:sql_types);
my $dbh = DBI->connect("dbi:SQLite:dbname=mem.sqlite");

use Benchmark qw(:all);
my $count = 40_000;

cmpthese($count, {
    'query_dbh' =>     sub {
        my $id = int(rand(20_000));
        my $sth = $dbh->prepare("SELECT str FROM t WHERE id = ?");
        $sth->execute($id);
        my ($str) = $sth->fetchrow_array;
        
        open F, ">", "foo.txt" or die $!;
        print F "id: $id, str: $str\n";
        close F;
    },
    'query_mem' =>     sub {
        my $id = int(rand(20_000));
    
        open F, ">", "foo.txt" or die $!;
        my $str = $memd->get($id);
        unless ($str) {
            my $sth = $dbh->prepare("SELECT str FROM t WHERE id = ?");
            $sth->execute($id);
            ($str) = $sth->fetchrow_array;
            
            $memd->set($id, $str);
        }
        print F "id: $id, str: $str\n";
        close F;
    }
});

            Rate query_mem query_dbf
query_mem 2723/s        --      -29%
query_dbh 3846/s       41%        --
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I consistently get results such as above, while I expected the memcache to slowly fill up and speed up the queries way faster than only accessing the file based db. What am I doing wrong, or are my expectations wrong?