diff --git a/core/src/main/java/google/registry/batch/ResaveAllEppResourcesAction.java b/core/src/main/java/google/registry/batch/ResaveAllEppResourcesAction.java
index dd125f3a9..a655fe1a8 100644
--- a/core/src/main/java/google/registry/batch/ResaveAllEppResourcesAction.java
+++ b/core/src/main/java/google/registry/batch/ResaveAllEppResourcesAction.java
@@ -14,6 +14,7 @@
 
 package google.registry.batch;
 
+import static google.registry.mapreduce.MapreduceRunner.PARAM_FAST;
 import static google.registry.model.ofy.ObjectifyService.ofy;
 import static google.registry.persistence.transaction.TransactionManagerFactory.tm;
 
@@ -24,6 +25,7 @@ import google.registry.mapreduce.MapreduceRunner;
 import google.registry.mapreduce.inputs.EppResourceInputs;
 import google.registry.model.EppResource;
 import google.registry.request.Action;
+import google.registry.request.Parameter;
 import google.registry.request.Response;
 import google.registry.request.auth.Auth;
 import javax.inject.Inject;
@@ -39,6 +41,14 @@ import javax.inject.Inject;
  * <p>Because there are no auth settings in the {@link Action} annotation, this command can only be
  * run internally, or by pretending to be internal by setting the X-AppEngine-QueueName header,
  * which only admin users can do.
+ *
+ * <p>If the <code>?fast=true</code> querystring parameter is passed, then entities that are not
+ * changed by {@link EppResource#cloneProjectedAtTime} will not be re-saved. This helps prevent
+ * mutation load on the DB and has the beneficial side effect of writing out smaller commit logs.
+ * Note that this does NOT pick up mutations caused by migrations using the {@link
+ * com.googlecode.objectify.annotation.OnLoad} annotation, so if you are running a one-off schema
+ * migration, do not use fast mode. Fast mode defaults to false for this reason, but is used by the
+ * monthly invocation of the mapreduce.
  */
 @Action(
     service = Action.Service.BACKEND,
@@ -48,7 +58,13 @@ public class ResaveAllEppResourcesAction implements Runnable {
 
   @Inject MapreduceRunner mrRunner;
   @Inject Response response;
-  @Inject ResaveAllEppResourcesAction() {}
+
+  @Inject
+  @Parameter(PARAM_FAST)
+  boolean isFast;
+
+  @Inject
+  ResaveAllEppResourcesAction() {}
 
   /**
    * The number of shards to run the map-only mapreduce on.
@@ -66,7 +82,7 @@ public class ResaveAllEppResourcesAction implements Runnable {
         .setModuleName("backend")
         .setDefaultMapShards(NUM_SHARDS)
         .runMapOnly(
-            new ResaveAllEppResourcesActionMapper(),
+            new ResaveAllEppResourcesActionMapper(isFast),
             ImmutableList.of(EppResourceInputs.createKeyInput(EppResource.class)))
         .sendLinkToMapreduceConsole(response);
   }
@@ -76,23 +92,33 @@ public class ResaveAllEppResourcesAction implements Runnable {
       extends Mapper<Key<EppResource>, Void, Void> {
 
     private static final long serialVersionUID = -7721628665138087001L;
-    public ResaveAllEppResourcesActionMapper() {}
+
+    private final boolean isFast;
+
+    ResaveAllEppResourcesActionMapper(boolean isFast) {
+      this.isFast = isFast;
+    }
 
     @Override
     public final void map(final Key<EppResource> resourceKey) {
-      tm()
-          .transact(
-              () -> {
-                EppResource projectedResource =
-                    ofy()
-                        .load()
-                        .key(resourceKey)
-                        .now()
-                        .cloneProjectedAtTime(tm().getTransactionTime());
-                ofy().save().entity(projectedResource).now();
-              });
-      getContext().incrementCounter(String.format("%s entities re-saved", resourceKey.getKind()));
+      boolean resaved =
+          tm().transact(
+                  () -> {
+                    EppResource originalResource = ofy().load().key(resourceKey).now();
+                    EppResource projectedResource =
+                        originalResource.cloneProjectedAtTime(tm().getTransactionTime());
+                    if (isFast && originalResource.equals(projectedResource)) {
+                      return false;
+                    } else {
+                      ofy().save().entity(projectedResource).now();
+                      return true;
+                    }
+                  });
+      getContext()
+          .incrementCounter(
+              String.format(
+                  "%s entities %s",
+                  resourceKey.getKind(), resaved ? "re-saved" : "with no changes skipped"));
     }
   }
 }
-
diff --git a/core/src/main/java/google/registry/env/alpha/default/WEB-INF/cron.xml b/core/src/main/java/google/registry/env/alpha/default/WEB-INF/cron.xml
index 3ce2a943c..67f8a96d9 100644
--- a/core/src/main/java/google/registry/env/alpha/default/WEB-INF/cron.xml
+++ b/core/src/main/java/google/registry/env/alpha/default/WEB-INF/cron.xml
@@ -80,7 +80,7 @@
   </cron>
 
   <cron>
-    <url><![CDATA[/_dr/task/resaveAllEppResources]]></url>
+    <url><![CDATA[/_dr/task/resaveAllEppResources?fast=true]]></url>
     <description>
       This job resaves all our resources, projected in time to "now".
       It is needed for "deleteOldCommitLogs" to work correctly.
diff --git a/core/src/main/java/google/registry/env/production/default/WEB-INF/cron.xml b/core/src/main/java/google/registry/env/production/default/WEB-INF/cron.xml
index 364370e58..59e3634b1 100644
--- a/core/src/main/java/google/registry/env/production/default/WEB-INF/cron.xml
+++ b/core/src/main/java/google/registry/env/production/default/WEB-INF/cron.xml
@@ -103,7 +103,7 @@
   </cron>
 
   <cron>
-    <url><![CDATA[/_dr/task/resaveAllEppResources]]></url>
+    <url><![CDATA[/_dr/task/resaveAllEppResources?fast=true]]></url>
     <description>
       This job resaves all our resources, projected in time to "now".
       It is needed for "deleteOldCommitLogs" to work correctly.
diff --git a/core/src/main/java/google/registry/env/qa/default/WEB-INF/cron.xml b/core/src/main/java/google/registry/env/qa/default/WEB-INF/cron.xml
index d89b22947..4d60720b9 100644
--- a/core/src/main/java/google/registry/env/qa/default/WEB-INF/cron.xml
+++ b/core/src/main/java/google/registry/env/qa/default/WEB-INF/cron.xml
@@ -21,7 +21,7 @@
   </cron>
 
   <cron>
-    <url><![CDATA[/_dr/task/resaveAllEppResources]]></url>
+    <url><![CDATA[/_dr/task/resaveAllEppResources?fast=true]]></url>
     <description>
       This job resaves all our resources, projected in time to "now".
       It is needed for "deleteOldCommitLogs" to work correctly.
diff --git a/core/src/main/java/google/registry/env/sandbox/default/WEB-INF/cron.xml b/core/src/main/java/google/registry/env/sandbox/default/WEB-INF/cron.xml
index 1ef1a2c65..52e423499 100644
--- a/core/src/main/java/google/registry/env/sandbox/default/WEB-INF/cron.xml
+++ b/core/src/main/java/google/registry/env/sandbox/default/WEB-INF/cron.xml
@@ -87,7 +87,7 @@
   </cron>
 
   <cron>
-    <url><![CDATA[/_dr/task/resaveAllEppResources]]></url>
+    <url><![CDATA[/_dr/task/resaveAllEppResources?fast=true]]></url>
     <description>
       This job resaves all our resources, projected in time to "now".
       It is needed for "deleteOldCommitLogs" to work correctly.
diff --git a/core/src/main/java/google/registry/mapreduce/MapreduceModule.java b/core/src/main/java/google/registry/mapreduce/MapreduceModule.java
index d3e3e44e9..285d61d8b 100644
--- a/core/src/main/java/google/registry/mapreduce/MapreduceModule.java
+++ b/core/src/main/java/google/registry/mapreduce/MapreduceModule.java
@@ -15,6 +15,7 @@
 package google.registry.mapreduce;
 
 import static google.registry.mapreduce.MapreduceRunner.PARAM_DRY_RUN;
+import static google.registry.mapreduce.MapreduceRunner.PARAM_FAST;
 import static google.registry.mapreduce.MapreduceRunner.PARAM_MAP_SHARDS;
 import static google.registry.mapreduce.MapreduceRunner.PARAM_REDUCE_SHARDS;
 import static google.registry.request.RequestParameters.extractBooleanParameter;
@@ -36,6 +37,12 @@ public final class MapreduceModule {
     return extractBooleanParameter(req, PARAM_DRY_RUN);
   }
 
+  @Provides
+  @Parameter(PARAM_FAST)
+  static boolean provideIsFast(HttpServletRequest req) {
+    return extractBooleanParameter(req, PARAM_FAST);
+  }
+
   @Provides
   @Parameter(PARAM_MAP_SHARDS)
   static Optional<Integer> provideMapShards(HttpServletRequest req) {
diff --git a/core/src/main/java/google/registry/mapreduce/MapreduceRunner.java b/core/src/main/java/google/registry/mapreduce/MapreduceRunner.java
index a0e16a5f2..87ebe607a 100644
--- a/core/src/main/java/google/registry/mapreduce/MapreduceRunner.java
+++ b/core/src/main/java/google/registry/mapreduce/MapreduceRunner.java
@@ -55,6 +55,7 @@ public class MapreduceRunner {
   public static final String PARAM_DRY_RUN = "dryRun";
   public static final String PARAM_MAP_SHARDS = "mapShards";
   public static final String PARAM_REDUCE_SHARDS = "reduceShards";
+  public static final String PARAM_FAST = "fast";
 
   private static final String BASE_URL = "/_dr/mapreduce/";
   private static final String QUEUE_NAME = "mapreduce";
diff --git a/core/src/main/java/google/registry/model/UpdateAutoTimestamp.java b/core/src/main/java/google/registry/model/UpdateAutoTimestamp.java
index c77c98fc8..dd75ad7ec 100644
--- a/core/src/main/java/google/registry/model/UpdateAutoTimestamp.java
+++ b/core/src/main/java/google/registry/model/UpdateAutoTimestamp.java
@@ -22,7 +22,7 @@ import javax.annotation.Nullable;
 import org.joda.time.DateTime;
 
 /**
- * A timestamp that auto-updates on each save to Datastore.
+ * A timestamp that auto-updates on each save to Datastore/Cloud SQL.
  *
  * @see UpdateAutoTimestampTranslatorFactory
  */
@@ -31,7 +31,7 @@ public class UpdateAutoTimestamp extends ImmutableObject {
   // When set to true, database converters/translators should do tha auto update.  When set to
   // false, auto update should be suspended (this exists to allow us to preserve the original value
   // during a replay).
-  static ThreadLocal<Boolean> autoUpdateEnabled = ThreadLocal.withInitial(() -> true);
+  private static ThreadLocal<Boolean> autoUpdateEnabled = ThreadLocal.withInitial(() -> true);
 
   DateTime timestamp;
 
diff --git a/core/src/test/java/google/registry/batch/ResaveAllEppResourcesActionTest.java b/core/src/test/java/google/registry/batch/ResaveAllEppResourcesActionTest.java
index 4698dd5fe..0e601cf9f 100644
--- a/core/src/test/java/google/registry/batch/ResaveAllEppResourcesActionTest.java
+++ b/core/src/test/java/google/registry/batch/ResaveAllEppResourcesActionTest.java
@@ -55,6 +55,19 @@ class ResaveAllEppResourcesActionTest extends MapreduceTestCase<ResaveAllEppReso
         .isGreaterThan(creationTime);
   }
 
+  @Test
+  void test_fastMode_doesNotResaveEntityWithNoChanges() throws Exception {
+    ContactResource contact = persistActiveContact("test123");
+    DateTime creationTime = contact.getUpdateTimestamp().getTimestamp();
+    assertThat(ofy().load().entity(contact).now().getUpdateTimestamp().getTimestamp())
+        .isEqualTo(creationTime);
+    ofy().clearSessionCache();
+    action.isFast = true;
+    runMapreduce();
+    assertThat(ofy().load().entity(contact).now().getUpdateTimestamp().getTimestamp())
+        .isEqualTo(creationTime);
+  }
+
   @Test
   void test_mapreduceResolvesPendingTransfer() throws Exception {
     DateTime now = DateTime.now(UTC);