If you're using a recent version of DBD::Pg, you shouldn't need to set the parameter at all. The only way how I was able to get the wrong string back was to set it to 0 but not set the binmode of STDOUT. Try experimenting with the following script: 
#!/usr/bin/perl
use warnings;
use strict;
use utf8;
use feature qw{ say };

use DBI;
use Encode;

for my $utf8 (1, -1, 0) {
    my $string = $utf8 ? 'Кирилл цагаан толгой'
                       : encode('UTF-8', 'Кирилл цагаан толгой');

    my $db = 'DBI'->connect('dbi:Pg:dbname=postgres', "", "");
    say $db->{pg_enable_utf8} = $utf8;

    $db->do('CREATE TABLE IF NOT EXISTS cyr (t TEXT)');
    $db->do('DELETE FROM cyr');

    my $insert = $db->prepare('INSERT INTO cyr (t) VALUES (?)');
    $insert->execute($string);

    my $select = $db->prepare('SELECT t FROM cyr');
    $select->execute;
    binmode *STDOUT, $utf8 ? ':encoding(UTF-8)' : ':raw';
    while (my @row = $select->fetchrow_array) {
        say @row;
    }
}

The script needs to be saved as UTF-8.

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

In reply to Re^3: JSON::XS Cyrillic unicode not saving properly by choroba
in thread JSON::XS Cyrillic unicode not saving properly by cormanaz

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.