diff --git a/dbcon/joblist/distributedenginecomm.cpp b/dbcon/joblist/distributedenginecomm.cpp
index 6fbbee3c5..01f29e75d 100644
--- a/dbcon/joblist/distributedenginecomm.cpp
+++ b/dbcon/joblist/distributedenginecomm.cpp
@@ -329,8 +329,11 @@ void DistributedEngineComm::Setup()
 
         for (j = 0; j < pmCount; j++)
         {
-            if (newClients[i]->isSameAddr(*fPmConnections[j]))
+            if (!fPmConnections.empty() && j < fPmConnections.size() &&
+                newClients[i]->isSameAddr(*fPmConnections[j]))
+            {
                 break;
+            }
         }
 
         if (j == pmCount)
diff --git a/dbcon/joblist/resourcemanager.cpp b/dbcon/joblist/resourcemanager.cpp
index 7ac2f98cb..b9f207d5b 100644
--- a/dbcon/joblist/resourcemanager.cpp
+++ b/dbcon/joblist/resourcemanager.cpp
@@ -171,6 +171,8 @@ ResourceManager::ResourceManager(bool runningInExeMgr) :
         totalUmMemLimit = pmJoinMemLimit;
     else
     {
+        // Installation.PMwithUM = y by default so RM prefers HashJoin.TotalPmUmMemory
+        // if it exists.
         string whichLimit = "TotalUmMemory";
         string pmWithUM = fConfig->getConfig("Installation", "PMwithUM");
 
diff --git a/oam/etc/Columnstore.xml b/oam/etc/Columnstore.xml
index b7caf0b62..df95e40ad 100644
--- a/oam/etc/Columnstore.xml
+++ b/oam/etc/Columnstore.xml
@@ -443,7 +443,7 @@
 		<InitialInstallFlag>y</InitialInstallFlag>
 		<SingleServerInstall>y</SingleServerInstall>
 		<ServerTypeInstall>2</ServerTypeInstall>
-		<PMwithUM>n</PMwithUM>
+		<PMwithUM>y</PMwithUM>
 		<MySQLRep>n</MySQLRep>
 		<DBRootStorageType>internal</DBRootStorageType>
 		<UMStorageType>internal</UMStorageType>