diff --git a/solr/contrib/dataimporthandler/CHANGES.txt b/solr/contrib/dataimporthandler/CHANGES.txt
index eb6d3afcc87..85acdcfcb96 100644
--- a/solr/contrib/dataimporthandler/CHANGES.txt
+++ b/solr/contrib/dataimporthandler/CHANGES.txt
@@ -19,6 +19,12 @@ New Features
 * SOLR-1499: Added SolrEntityProcessor that imports data from another Solr core or instance based on a specified query.
              (Lance Norskog, Erik Hatcher, Pulkit Singhal, Ahmet Arslan, Luca Cavanna, Martijn van Groningen)
 
+Changes in Runtime Behavior
+----------------------
+* SOLR-3142: Imports no longer default optimize to true, instead false. If you want to force all segments to be merged
+             into one, you can specify this parameter yourself. NOTE: this can be very expensive operation and usually
+             does not make sense for delta-imports.  (Robert MUir)
+
 ==================  3.5.0 ==================
 
 Bug Fixes
diff --git a/solr/contrib/dataimporthandler/src/java/org/apache/solr/handler/dataimport/DataImporter.java b/solr/contrib/dataimporthandler/src/java/org/apache/solr/handler/dataimport/DataImporter.java
index 8239f333670..d8b3494932d 100644
--- a/solr/contrib/dataimporthandler/src/java/org/apache/solr/handler/dataimport/DataImporter.java
+++ b/solr/contrib/dataimporthandler/src/java/org/apache/solr/handler/dataimport/DataImporter.java
@@ -523,7 +523,7 @@ public class DataImporter {
 
     public boolean commit = true;
 
-    public boolean optimize = true;
+    public boolean optimize = false;
 
     public int start = 0;
 
@@ -571,7 +571,7 @@ public class DataImporter {
       if (requestParams.containsKey("clean"))
         clean = StrUtils.parseBool((String) requestParams.get("clean"),true);
       if (requestParams.containsKey("optimize")) {
-        optimize = StrUtils.parseBool((String) requestParams.get("optimize"),true);
+        optimize = StrUtils.parseBool((String) requestParams.get("optimize"),false);
         if (optimize)
           commit = true;
       }