diff --git a/mercurial/setdiscovery.py b/mercurial/setdiscovery.py
--- a/mercurial/setdiscovery.py
+++ b/mercurial/setdiscovery.py
@@ -107,12 +107,16 @@
     :size: the maximum size of the sample"""
     sample = dag.headsetofconnecteds(nodes)
     if len(sample) >= size:
-        return _limitsample(sample, size)
+        # Return full set of heads, without limiting
+        return sample
     _updatesample(dag, None, sample, quicksamplesize=size)
     return sample
 
 def _takefullsample(dag, nodes, size):
     sample = dag.headsetofconnecteds(nodes)
+    if len(sample) >= size:
+        # Return full set of heads, without limiting
+        return sample
     # update from heads
     _updatesample(dag, nodes, sample)
     # update from roots