Use RepositoryGraphCache to service diffusion.lastmodifiedquery

Summary:
Ref T2683. At least locally, browse views are now nearly instantaneous, even in Mercurial. We also fall back to what we were doing before if we miss or take too long, so this shouldn't make things very much worse even in extreme cases.

For a local `hg` repo, the time we spend pulling browse stuff has dropped from ~3,000ms to ~20ms. This is probably atypical, but not completely crazy or rigged or anything.

Test Plan: Viewed Git, Subversion and Mercurial repositories and observed dramatically better performance in Git and Mercurial as they took advantage of the cache.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley, jhurwitz

Maniphest Tasks: T2683

Differential Revision: https://secure.phabricator.com/D9047

src/applications/diffusion/conduit/ConduitAPI_diffusion_lastmodifiedquery_Method.php

@@ -21,23 +21,28 @@ final class ConduitAPI_diffusion_lastmodifiedquery_Method
     $drequest = $this->getDiffusionRequest();
     $repository = $drequest->getRepository();
 
-    $result = array();
+    $paths = $request->getValue('paths');
-    foreach ($request->getValue('paths') as $path => $commit) {
+    $results = $this->loadCommitsFromCache($paths);
+
+    foreach ($paths as $path => $commit) {
+      if (array_key_exists($path, $results)) {
+        continue;
+      }
       list($hash) = $repository->execxLocalCommand(
         'log -n1 --format=%%H %s -- %s',
         $commit,
         $path);
-      $result[$path] = trim($hash);
+      $results[$path] = trim($hash);
     }
 
-    return $result;
+    return $results;
   }
 
   protected function getSVNResult(ConduitAPIRequest $request) {
     $drequest = $this->getDiffusionRequest();
     $repository = $drequest->getRepository();
 
-    $result = array();
+    $results = array();
     foreach ($request->getValue('paths') as $path => $commit) {
       $history_result = DiffusionQuery::callConduitWithDiffusionRequest(
         $request->getUser(),
@@ -55,30 +60,93 @@ final class ConduitAPI_diffusion_lastmodifiedquery_Method
       $history_array = DiffusionPathChange::newFromConduit(
         $history_result['pathChanges']);
       if ($history_array) {
-        $result[$path] = head($history_array)
+        $results[$path] = head($history_array)
           ->getCommit()
           ->getCommitIdentifier();
       }
     }
 
-    return $result;
+    return $results;
   }
 
   protected function getMercurialResult(ConduitAPIRequest $request) {
     $drequest = $this->getDiffusionRequest();
     $repository = $drequest->getRepository();
 
-    $result = array();
+    $paths = $request->getValue('paths');
-    foreach ($request->getValue('paths') as $path => $commit) {
+    $results = $this->loadCommitsFromCache($paths);
+
+    foreach ($paths as $path => $commit) {
+      if (array_key_exists($path, $results)) {
+        continue;
+      }
+
       list($hash) = $repository->execxLocalCommand(
         'log --template %s --limit 1 --removed --rev %s -- %s',
         '{node}',
         hgsprintf('reverse(ancestors(%s))',  $commit),
         nonempty(ltrim($path, '/'), '.'));
-      $result[$path] = trim($hash);
+      $results[$path] = trim($hash);
     }
 
-    return $result;
+    return $results;
+  }
+
+  private function loadCommitsFromCache(array $map) {
+    $drequest = $this->getDiffusionRequest();
+    $repository = $drequest->getRepository();
+
+    $path_map = id(new DiffusionPathIDQuery(array_keys($map)))
+      ->loadPathIDs();
+
+    $commit_query = id(new DiffusionCommitQuery())
+      ->setViewer($drequest->getUser())
+      ->withRepository($repository)
+      ->withIdentifiers(array_values($map));
+    $commit_query->execute();
+
+    $commit_map = $commit_query->getIdentifierMap();
+    $commit_map = mpull($commit_map, 'getID');
+
+    $graph_cache = new PhabricatorRepositoryGraphCache();
+
+    $results = array();
+    foreach ($map as $path => $commit) {
+      $path_id = idx($path_map, $path);
+      if (!$path_id) {
+        continue;
+      }
+      $commit_id = idx($commit_map, $commit);
+      if (!$commit_id) {
+        continue;
+      }
+
+      $cache_result = $graph_cache->loadLastModifiedCommitID(
+        $commit_id,
+        $path_id);
+
+      if ($cache_result !== false) {
+        $results[$path] = $cache_result;
+      }
+    }
+
+    if ($results) {
+      $commits = id(new DiffusionCommitQuery())
+        ->setViewer($drequest->getUser())
+        ->withRepository($repository)
+        ->withIDs($results)
+        ->execute();
+      foreach ($results as $path => $id) {
+        $commit = idx($commits, $id);
+        if ($commit) {
+          $results[$path] = $commit->getCommitIdentifier();
+        } else {
+          unset($results[$path]);
+        }
+      }
+    }
+
+    return $results;
   }
 
 }

src/applications/diffusion/view/DiffusionBrowseTableView.php

@@ -113,6 +113,7 @@ final class DiffusionBrowseTableView extends DiffusionView {
           'uri'   => (string)$request->generateURI(
             array(
               'action' => 'lastmodified',
+              'stable' => true,
             )),
           'map' => $need_pull,
         ));

src/applications/repository/graphcache/PhabricatorRepositoryGraphCache.php

@@ -200,7 +200,7 @@ final class PhabricatorRepositoryGraphCache {
     if ($prefix === null) {
       $self = get_class($this);
       $size = $this->getBucketSize();
-      $prefix = "{$self}:{$size}:1:";
+      $prefix = "{$self}:{$size}:2:";
     }
 
     return $prefix.$bucket_key;