diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index ea44bae3a9..43580a51f7 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -684,6 +684,7 @@ phutil_register_library_map(array(
     'PhabricatorFlagQuery' => 'applications/flag/query/PhabricatorFlagQuery.php',
     'PhabricatorFormExample' => 'applications/uiexample/examples/PhabricatorFormExample.php',
     'PhabricatorGarbageCollectorDaemon' => 'infrastructure/daemon/PhabricatorGarbageCollectorDaemon.php',
+    'PhabricatorGitGraphStream' => 'applications/repository/daemon/PhabricatorGitGraphStream.php',
     'PhabricatorGoodForNothingWorker' => 'infrastructure/daemon/workers/worker/PhabricatorGoodForNothingWorker.php',
     'PhabricatorHandleObjectSelectorDataView' => 'applications/phid/handle/view/PhabricatorHandleObjectSelectorDataView.php',
     'PhabricatorHash' => 'infrastructure/util/PhabricatorHash.php',
diff --git a/src/applications/repository/daemon/PhabricatorGitGraphStream.php b/src/applications/repository/daemon/PhabricatorGitGraphStream.php
new file mode 100644
index 0000000000..62a2382098
--- /dev/null
+++ b/src/applications/repository/daemon/PhabricatorGitGraphStream.php
@@ -0,0 +1,96 @@
+<?php
+
+/*
+ * Copyright 2012 Facebook, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+final class PhabricatorGitGraphStream {
+
+  private $repository;
+  private $iterator;
+
+  private $parents        = array();
+  private $dates          = array();
+
+  public function __construct(
+    PhabricatorRepository $repository,
+    $start_commit) {
+
+    $this->repository = $repository;
+
+    $future = $repository->getLocalCommandFuture(
+      "log --format=%s %s --",
+      '%H%x01%P%x01%ct',
+      $start_commit);
+
+    $this->iterator = new LinesOfALargeExecFuture($future);
+    $this->iterator->setDelimiter("\n");
+    $this->iterator->rewind();
+  }
+
+  public function getParents($commit) {
+    if (!isset($this->parents[$commit])) {
+      $this->parseUntil($commit);
+    }
+    return $this->parents[$commit];
+  }
+
+  public function getCommitDate($commit) {
+    if (!isset($this->dates[$commit])) {
+      $this->parseUntil($commit);
+    }
+    return $this->dates[$commit];
+  }
+
+  private function parseUntil($commit) {
+    if ($this->isParsed($commit)) {
+      return;
+    }
+
+    $gitlog = $this->iterator;
+
+    while ($gitlog->valid()) {
+      $line = $gitlog->current();
+      $gitlog->next();
+
+      $line = trim($line);
+      if (!strlen($line)) {
+        break;
+      }
+      list($hash, $parents, $epoch) = explode("\1", $line);
+
+      if ($parents) {
+        $parents = explode(' ', $parents);
+      } else {
+        // First commit.
+        $parents = array();
+      }
+
+      $this->dates[$hash] = $epoch;
+      $this->parents[$hash] = $parents;
+
+      if ($this->isParsed($commit)) {
+        return;
+      }
+    }
+
+    throw new Exception("No such commit '{$commit}' in repository!");
+  }
+
+  private function isParsed($commit) {
+    return isset($this->dates[$commit]);
+  }
+
+}
diff --git a/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php b/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php
index b887404df8..4eb9ccebeb 100644
--- a/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php
+++ b/src/applications/repository/daemon/PhabricatorRepositoryPullLocalDaemon.php
@@ -614,12 +614,11 @@ final class PhabricatorRepositoryPullLocalDaemon
 
     $seen_parent = array();
 
+    $stream = new PhabricatorGitGraphStream($repository, $commit);
+
     while (true) {
       $target = array_pop($discover);
-      list($parents) = $repository->execxLocalCommand(
-        'log -n1 --pretty="%%P" %s',
-        $target);
-      $parents = array_filter(explode(' ', trim($parents)));
+      $parents = $stream->getParents($target);
       foreach ($parents as $parent) {
         if (isset($seen_parent[$parent])) {
           // We end up in a loop here somehow when we parse Arcanist if we
@@ -656,9 +655,7 @@ final class PhabricatorRepositoryPullLocalDaemon
 
     while (true) {
       $target = array_pop($insert);
-      list($epoch) = $repository->execxLocalCommand(
-        'log -n1 --pretty="%%ct" %s',
-        $target);
+      $epoch = $stream->getCommitDate($target);
       $epoch = trim($epoch);
 
       if ($branch !== null) {