exlain_url sql function

explain_url.sql

CREATE OR REPLACE FUNCTION public.explain_url(query text)
 RETURNS text
 LANGUAGE plperlu
AS $function$

        my $query = shift;
        elog(ERROR,"not an explain query") unless $query =~ /^\s*explain\s/i;
        my $rv = spi_exec_query($query);
        my $nrows = $rv->{processed};
        my $text = $query . "\n  QUERY PLAN\n-------------------\n";
        foreach my $rn (0 .. $nrows-1) 
        { 
            $text = $text . "$rv->{rows}[$rn]->{'QUERY PLAN'}\n"; 
        }

        use HTTP::Request::Common qw(POST);
        use LWP::UserAgent;
        my $ua = LWP::UserAgent->new;

        my $req = POST ' http://explain.depesz.com/',
             [ plan => $text ];

        my $resp = $ua->request($req);
        my $loc = $resp->header('Location');
        $loc =~ s!^/!http://explain.depesz.com/!;
        return $loc;
$function$;