use Encode qw/decode is_utf8/;
use DBI;
my $dbh = DBI->connect("dbi:Pg:dbname=ab", "***", "***", { RaiseError => 1, AutoCommit => 0 });
my $a = decode('iso8859-1', "\x{92}");
$dbh->do("CREATE TABLE a (a text)");
$dbh->do("INSERT INTO a(a) VALUES (?)",{}, $a);
my($b) = $dbh->selectrow_array("SELECT * FROM a");

if($b eq $a){
    print "Equals a: $a, b: $b\n";
}else{
    print "Not equals a: $a, b: $b\n";
}
print "a is_utf8: " , is_utf8($a), "\n";
print "b is_utf8: " , is_utf8($b), "\n";
$dbh->rollback;
$dbh->disconnect;

##</code><code>##

Not equals a: ’, b: Â’
a is_utf8: 1
b is_utf8: