HTTP needs to be a POST after a certain size

I'm querying a view using the PHP SDK using the view method, $object->view($ddocname [, $viewname ] [, $viewoptions ]), and finding that when I pass in a certain number of keys in the viewoptions param, the method silently fails and just returns null. It appears that 164 keys is OK, but 179 is not. I didn't see documentation indicating a key limit and would expect an error if there were.
Here's the call:
// 179 keys breaks, 164 OK
$result = $this->cb->view(self::VIEW_DAP,'modelcount',array('keys' => $keys,
'group_level' => 2,
'group' => true,
'skip' => 0)

Here's a link to the forum thread I created:
http://www.couchbase.com/forums/thread/key-limit-view-queries

As you'll see in the responses, this is probably a much more general issue that the PHP SDK uses GET calls that have a string length limit. It seems that the SDK should either use POSTs to avoid the limit or document the size limits in the documentation.