diff --git a/src/applications/cache/spec/PhabricatorDataCacheSpec.php b/src/applications/cache/spec/PhabricatorDataCacheSpec.php
index ca840c10f8..0d78f01ff5 100644
--- a/src/applications/cache/spec/PhabricatorDataCacheSpec.php
+++ b/src/applications/cache/spec/PhabricatorDataCacheSpec.php
@@ -1,84 +1,132 @@
 <?php
 
 final class PhabricatorDataCacheSpec extends PhabricatorCacheSpec {
 
+  private $cacheSummary;
+
+  public function setCacheSummary(array $cache_summary) {
+    $this->cacheSummary = $cache_summary;
+    return $this;
+  }
+
+  public function getCacheSummary() {
+    return $this->cacheSummary;
+  }
+
   public static function getActiveCacheSpec() {
     $spec = new PhabricatorDataCacheSpec();
     // NOTE: If APCu is installed, it reports that APC is installed.
     if (extension_loaded('apc') && !extension_loaded('apcu')) {
       return self::getAPCSpec($spec);
     } else if (extension_loaded('apcu')) {
       return self::getAPCuSpec($spec);
     } else {
       return self::getNoneSpec($spec);
     }
   }
 
   private static function getAPCSpec(PhabricatorDataCacheSpec $spec) {
     $spec
       ->setName(pht('APC User Cache'))
       ->setVersion(phpversion('apc'));
 
     if (ini_get('apc.enabled')) {
       $spec->setIsEnabled(true);
       self::getAPCCommonSpec($spec);
     } else {
       $spec->setIsEnabled(false);
       $spec->newIssue(
         pht('Enable APC'),
         pht(
           'The "APC" extension is currently disabled. Set "apc.enabled" to '.
           'true to provide caching.'),
         'apc.enabled');
     }
 
     return $spec;
   }
 
   private static function getAPCuSpec(PhabricatorDataCacheSpec $spec) {
     $spec
       ->setName(pht('APCu'))
       ->setVersion(phpversion('apcu'));
 
     if (ini_get('apc.enabled')) {
       $spec->setIsEnabled(true);
       self::getAPCCommonSpec($spec);
     } else {
       $spec->setIsEnabled(false);
       $spec->newissue(
         pht('Enable APCu'),
         pht(
           'The "APCu" extension is currently disabled. Set '.
           '"apc.enabled" to true to provide caching.'),
         'apc.enabled');
     }
 
     return $spec;
   }
 
   private static function getNoneSpec(PhabricatorDataCacheSpec $spec) {
     if (version_compare(phpversion(), '5.5', '>=')) {
       $spec->newIssue(
         pht('Install APCu'),
         pht(
           'Install the "APCu" PHP extension to provide data caching.'));
     } else {
       $spec->newIssue(
         pht('Install APC'),
         pht(
           'Install the "APC" PHP extension to provide data caching.'));
     }
 
     return $spec;
   }
 
   private static function getAPCCommonSpec(PhabricatorDataCacheSpec $spec) {
     $mem = apc_sma_info();
     $spec->setTotalMemory($mem['num_seg'] * $mem['seg_size']);
 
     $info = apc_cache_info('user');
     $spec->setUsedMemory($info['mem_size']);
     $spec->setEntryCount(count($info['cache_list']));
+
+    $cache = $info['cache_list'];
+    $state = array();
+    foreach ($cache as $item) {
+      $key = self::getKeyPattern($item['info']);
+      if (empty($state[$key])) {
+        $state[$key] = array(
+          'max' => 0,
+          'total' => 0,
+          'count' => 0,
+        );
+      }
+      $state[$key]['max'] = max($state[$key]['max'], $item['mem_size']);
+      $state[$key]['total'] += $item['mem_size'];
+      $state[$key]['count']++;
+    }
+
+    $spec->setCacheSummary($state);
+  }
+
+  private static function getKeyPattern($key) {
+    // If this key isn't in the current cache namespace, don't reveal any
+    // information about it.
+    $namespace = PhabricatorEnv::getEnvConfig('phabricator.cache-namespace');
+    if (strncmp($key, $namespace.':', strlen($namespace) + 1)) {
+      return '<other-namespace>';
+    }
+
+    $key = preg_replace('/(?<![a-zA-Z])\d+(?![a-zA-Z])/', 'N', $key);
+    $key = preg_replace('/PHID-[A-Z]{4}-[a-z0-9]{20}/', 'PHID', $key);
+
+    // TODO: We should probably standardize how digests get embedded into cache
+    // keys to make this rule more generic.
+    $key = preg_replace('/:celerity:.*$/', ':celerity:X', $key);
+    $key = preg_replace('/:pkcs8:.*$/', ':pkcs8:X', $key);
+
+    return $key;
   }
 
 }
diff --git a/src/applications/config/controller/PhabricatorConfigCacheController.php b/src/applications/config/controller/PhabricatorConfigCacheController.php
index a0211d1c84..cf2d78142d 100644
--- a/src/applications/config/controller/PhabricatorConfigCacheController.php
+++ b/src/applications/config/controller/PhabricatorConfigCacheController.php
@@ -1,148 +1,187 @@
 <?php
 
 final class PhabricatorConfigCacheController
   extends PhabricatorConfigController {
 
   public function handleRequest(AphrontRequest $request) {
     $viewer = $this->getViewer();
 
     $nav = $this->buildSideNavView();
     $nav->selectFilter('cache/');
 
     $title = pht('Cache Status');
 
     $crumbs = $this
       ->buildApplicationCrumbs()
       ->addTextCrumb(pht('Cache Status'));
 
     $code_box = $this->renderCodeBox();
     $data_box = $this->renderDataBox();
 
     $nav->appendChild(
       array(
         $crumbs,
         $code_box,
         $data_box,
       ));
 
     return $this->buildApplicationPage(
       $nav,
       array(
         'title' => $title,
       ));
   }
 
   private function renderCodeBox() {
     $cache = PhabricatorOpcodeCacheSpec::getActiveCacheSpec();
 
     $properties = id(new PHUIPropertyListView());
 
     $this->renderCommonProperties($properties, $cache);
 
     return id(new PHUIObjectBoxView())
       ->setFormErrors($this->renderIssues($cache->getIssues()))
       ->setHeaderText(pht('Opcode Cache'))
       ->addPropertyList($properties);
   }
 
   private function renderDataBox() {
     $cache = PhabricatorDataCacheSpec::getActiveCacheSpec();
 
     $properties = id(new PHUIPropertyListView());
 
     $this->renderCommonProperties($properties, $cache);
 
+    $table = null;
+    if ($cache->getName() !== null) {
+      $total_memory = $cache->getTotalMemory();
+
+      $summary = $cache->getCacheSummary();
+      $summary = isort($summary, 'total');
+      $summary = array_reverse($summary, true);
+
+      $rows = array();
+      foreach ($summary as $key => $info) {
+        $rows[] = array(
+          $key,
+          pht('%s', new PhutilNumber($info['count'])),
+          phutil_format_bytes($info['max']),
+          phutil_format_bytes($info['total']),
+          sprintf('%.1f%%', (100 * ($info['total'] / $total_memory))),
+        );
+      }
+
+      $table = id(new AphrontTableView($rows))
+        ->setHeaders(
+          array(
+            pht('Pattern'),
+            pht('Count'),
+            pht('Largest'),
+            pht('Total'),
+            pht('Usage'),
+          ))
+        ->setColumnClasses(
+          array(
+            'wide',
+            'n',
+            'n',
+            'n',
+            'n',
+          ));
+    }
+
     return id(new PHUIObjectBoxView())
       ->setHeaderText(pht('Data Cache'))
-      ->addPropertyList($properties);
+      ->addPropertyList($properties)
+      ->appendChild($table);
   }
 
   private function renderCommonProperties(
     PHUIPropertyListView $properties,
     PhabricatorCacheSpec $cache) {
 
     if ($cache->getName() !== null) {
       $name = $this->renderYes($cache->getName());
     } else {
       $name = $this->renderNo(pht('None'));
     }
     $properties->addProperty(pht('Cache'), $name);
 
     if ($cache->getIsEnabled()) {
       $enabled = $this->renderYes(pht('Enabled'));
     } else {
       $enabled = $this->renderNo(pht('Not Enabled'));
     }
     $properties->addProperty(pht('Enabled'), $enabled);
 
     $version = $cache->getVersion();
     if ($version) {
       $properties->addProperty(pht('Version'), $this->renderInfo($version));
     }
 
     if ($cache->getName() === null) {
       return;
     }
 
     $mem_total = $cache->getTotalMemory();
     $mem_used = $cache->getUsedMemory();
 
     if ($mem_total) {
       $percent = 100 * ($mem_used / $mem_total);
 
       $properties->addProperty(
         pht('Memory Usage'),
         pht(
           '%s of %s',
           phutil_tag('strong', array(), sprintf('%.1f%%', $percent)),
           phutil_format_bytes($mem_total)));
     }
 
     $entry_count = $cache->getEntryCount();
     if ($entry_count !== null) {
       $properties->addProperty(
         pht('Cache Entries'),
         pht('%s', new PhutilNumber($entry_count)));
     }
 
   }
 
   private function renderIssues(array $issues) {
     $result = array();
     foreach ($issues as $issue) {
       $title = $issue['title'];
       $body = $issue['body'];
       $result[] = array(
         phutil_tag('strong', array(), $title.':'),
         ' ',
         $body,
       );
     }
     return $result;
   }
 
   private function renderYes($info) {
     return array(
       id(new PHUIIconView())->setIconFont('fa-check', 'green'),
       ' ',
       $info,
     );
   }
 
   private function renderNo($info) {
     return array(
       id(new PHUIIconView())->setIconFont('fa-times-circle', 'red'),
       ' ',
       $info,
     );
   }
 
   private function renderInfo($info) {
     return array(
       id(new PHUIIconView())->setIconFont('fa-info-circle', 'grey'),
       ' ',
       $info,
     );
   }
 
 }