[Pgpool-general] Problems using pgpool, perl DBI, and prepared statements

[Kevin Murphy]

I'm trying out pgpool for the first time, and I'm getting errors like 
this in my Perl application:

DBD::Pg::st execute failed: ERROR:  prepared statement "dbdpg_1" already 
exists

In the sample program below, I get no errors if I create just one DB 
handle (set $mode to 'one-connection').  However, if the DB handle is 
connected and disconnected around each query (set $mode to 
'multiple-connections'), I get the error on the second iteration.  If 
the program is changed to do just one iteration, it always succeeds -- 
until it has been run one more time than there are pgpool connection 
processes running.  It seems that the query can be prepared only once 
through any given pgpool process ....

I'm using pgpool 2.6.5, PostgreSQL 8.1, Perl 5.8.6, DBI 1.48, DBD::Pg 
1.43, on Mac OS X 10.4.3.

I feel that I must be missing something obvious.

Thanks,
Kevin Murphy

# begin
use strict;
use warnings;
use DBI;
my $mode = 'multiple-connections';
my ($dbh, $sth);
if ($mode eq 'one-connection') {
    $dbh = 
DBI->connect("dbi:Pg:dbname=testdb;host=127.0.0.1;port=9999",'testuser', 
'testpass')
        or die DBI->errstr;
}
foreach my $iteration (1..20) {
    unless ($mode eq 'one-connection') {
        $dbh = 
DBI->connect("dbi:Pg:dbname=testdb;host=127.0.0.1;port=9999",'testuser', 
'testpass')
            or die DBI->errstr;
    }
    $sth = $dbh->prepare('select 1 from pg_class where relname = ?') or 
die $dbh->errstr;
    $sth->execute('views') or die $sth->errstr;
    while (my @row = $sth->fetchrow_array) {
    }
    $sth->finish;
    unless ($mode eq 'one-connection') {
        $dbh->disconnect;
    }
    print "Iteration $iteration OK\n";
}
if ($mode eq 'one-connection') {
    $dbh->disconnect;
}
#end