Description:
------------
From http://www.php.net/manual/en/info.configuration.php#ini.max-input-vars
it stated that the limitation is only on each nested level of multidimensional 
array. But actually, it limit on the root level of variabel. Easy speaking, it 
count appearance of '&' in input.

this script should work since each level only contain 900 var, but it stopped 
after 1000th appearance of '&'

it may be connected to Bug #60728

Test script:
---------------
$a = array();
for ($i = 0; $i < 900; $i++)
{
  if ($i != 899) $a['asd'.$i] = "$i";
  else for ($j = 0; $j < 900; $j++)
    $a['asd'.$i]['qwe'.$j] = "$i - $j";
}
$a = http_build_query($a);
parse_str($a,$b);
$b = http_build_query($b);
echo count(explode('&',$a))."\n";
echo count(explode('&',$b))."\n";

Expected result:
----------------
1799
1799

Actual result:
--------------
Warning: parse_str(): Input variables exceeded 1000. To increase the limit change 
max_input_vars in php.ini. in var://_POST/script on line 9
1799
1000