diff --git a/src/mon/PGMap.cc b/src/mon/PGMap.cc
index 3aeb7962682..938e2862aaa 100644
--- a/src/mon/PGMap.cc
+++ b/src/mon/PGMap.cc
@@ -309,8 +309,11 @@ void PGMap::stat_pg_sub(const pg_t &pgid, const pg_stat_t &s)
   pg_sum.sub(s);
   if (s.state & PG_STATE_CREATING) {
     creating_pgs.erase(pgid);
-    if (s.acting.size())
+    if (s.acting.size()) {
       creating_pgs_by_osd[s.acting[0]].erase(pgid);
+      if (creating_pgs_by_osd[s.acting[0]].size() == 0)
+        creating_pgs_by_osd.erase(s.acting[0]);
+    }
   }
 }
 
diff --git a/src/mon/PGMonitor.cc b/src/mon/PGMonitor.cc
index 6a6dd60b84b..b66ae895225 100644
--- a/src/mon/PGMonitor.cc
+++ b/src/mon/PGMonitor.cc
@@ -775,8 +775,11 @@ void PGMonitor::send_pg_creates()
     vector<int> acting;
     int nrep = mon->osdmon()->osdmap.pg_to_acting_osds(on, acting);
 
-    if (s.acting.size())
+    if (s.acting.size()) {
       pg_map.creating_pgs_by_osd[s.acting[0]].erase(pgid);
+      if (pg_map.creating_pgs_by_osd[s.acting[0]].size() == 0)
+        pg_map.creating_pgs_by_osd.erase(s.acting[0]);
+    }
     s.acting = acting;
 
     // don't send creates for localized pgs
@@ -812,6 +815,7 @@ void PGMonitor::send_pg_creates(int osd, Connection *con)
   map<int, set<pg_t> >::iterator p = pg_map.creating_pgs_by_osd.find(osd);
   if (p == pg_map.creating_pgs_by_osd.end())
     return;
+  assert(p->second.size() > 0);
 
   dout(20) << "send_pg_creates osd." << osd << " pgs " << p->second << dendl;
   MOSDPGCreate *m = new MOSDPGCreate(mon->osdmon()->osdmap.get_epoch());