Hi pg, I used the following to do the test earlier:

#!C:/Perl/bin/perl
use strict;
use DBI;
use DBD::Sybase;
use Data::Dumper;

my $dbh = DBI->connect("dbi:Sybase:server=SERVER;database=DATABASE",  
+                          "USER","PASSWORD")
    or die "Can not connect to database!";

my $sth = $dbh->prepare( qq{ select amount from trades_gdw_total });

$sth->execute();

while (my $rows = $sth->fetchall_arrayref([0], 3)) {
  last if ($#$rows <= 0);
  for (@$rows) {
    print "got @$_\n";
  }
  print "---\n";
}
[download]

And I got the desired behaviour, with no errors reported. I am using DBI version 1.39, with DBD::Sybase, by the way.

I studied the source code of DBI, and extracted the following code concerning the behaviour of fetchall_arrayref:

  # we copy the array here because fetch (currently) always
  # returns the same array ref. XXX

  if ($slice && @$slice) {
    
    # if called with [0]

    $max_rows = -1 unless defined $max_rows;
    push @rows, [ @{$row}[ @$slice] ]
      while($max_rows-- and $row = $sth->fetch);
  }
  elsif (defined $max_rows) {

    # if called with undef

    $max_rows = -1 unless defined $max_rows;
    push @rows, [ @$row ]
      while($max_rows-- and $row = $sth->fetch);
  }
  else {
    push @rows, [ @$row ] while($row = $sth->fetch);
  }
[download]

And everything points to fetch.