diff --git a/conf/default.conf.php b/conf/default.conf.php
index 8b81ceb8a3..37d1db1f6a 100644
--- a/conf/default.conf.php
+++ b/conf/default.conf.php
@@ -180,9 +180,6 @@ return array(
   // (e.g., db.example.com:1234).
   'mysql.host' => 'localhost',
 
-  // The number of times to try reconnecting to the MySQL database
-  'mysql.connection-retries' => 3,
-
   // Phabricator supports PHP extensions MySQL and MySQLi. It is possible to
   // implement also other access mechanism (e.g. PDO_MySQL). The class must
   // extend AphrontMySQLDatabaseConnectionBase.
diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
index 55bbad9e3d..9c12935261 100644
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -938,6 +938,7 @@ phutil_register_library_map(array(
     'PhabricatorMetaMTAViewController' => 'applications/metamta/controller/PhabricatorMetaMTAViewController.php',
     'PhabricatorMetaMTAWorker' => 'applications/metamta/PhabricatorMetaMTAWorker.php',
     'PhabricatorMustVerifyEmailController' => 'applications/auth/controller/PhabricatorMustVerifyEmailController.php',
+    'PhabricatorMySQLConfigOptions' => 'applications/config/option/PhabricatorMySQLConfigOptions.php',
     'PhabricatorMySQLFileStorageEngine' => 'applications/files/engine/PhabricatorMySQLFileStorageEngine.php',
     'PhabricatorNotificationBuilder' => 'applications/notification/builder/PhabricatorNotificationBuilder.php',
     'PhabricatorNotificationClearController' => 'applications/notification/controller/PhabricatorNotificationClearController.php',
@@ -2262,6 +2263,7 @@ phutil_register_library_map(array(
     'PhabricatorMetaMTAViewController' => 'PhabricatorMetaMTAController',
     'PhabricatorMetaMTAWorker' => 'PhabricatorWorker',
     'PhabricatorMustVerifyEmailController' => 'PhabricatorAuthController',
+    'PhabricatorMySQLConfigOptions' => 'PhabricatorApplicationConfigOptions',
     'PhabricatorMySQLFileStorageEngine' => 'PhabricatorFileStorageEngine',
     'PhabricatorNotificationClearController' => 'PhabricatorNotificationController',
     'PhabricatorNotificationController' => 'PhabricatorController',
diff --git a/src/applications/config/controller/PhabricatorConfigEditController.php b/src/applications/config/controller/PhabricatorConfigEditController.php
index c0753e25f1..14c88b2c9a 100644
--- a/src/applications/config/controller/PhabricatorConfigEditController.php
+++ b/src/applications/config/controller/PhabricatorConfigEditController.php
@@ -100,6 +100,15 @@ final class PhabricatorConfigEditController
       $error_view = id(new AphrontErrorView())
         ->setTitle(pht('You broke everything!'))
         ->setErrors($errors);
+    } else if ($option->getHidden()) {
+      $msg = pht(
+        "This configuration is hidden and can not be edited or viewed from ".
+        "the web interface.");
+
+      $error_view = id(new AphrontErrorView())
+        ->setTitle(pht('Configuration Hidden'))
+        ->setSeverity(AphrontErrorView::SEVERITY_WARNING)
+        ->appendChild('<p>'.phutil_escape_html($msg).'</p>');
     } else if ($option->getLocked()) {
       $msg = pht(
         "This configuration is locked and can not be edited from the web ".
@@ -111,10 +120,14 @@ final class PhabricatorConfigEditController
         ->appendChild('<p>'.phutil_escape_html($msg).'</p>');
     }
 
-    $control = $this->renderControl(
-      $option,
-      $display_value,
-      $e_value);
+    if ($option->getHidden()) {
+      $control = null;
+    } else {
+      $control = $this->renderControl(
+        $option,
+        $display_value,
+        $e_value);
+    }
 
     $engine = new PhabricatorMarkupEngine();
     $engine->addObject($option, 'description');
@@ -135,14 +148,15 @@ final class PhabricatorConfigEditController
           ->setValue($description))
       ->appendChild($control);
 
+    $submit_control = id(new AphrontFormSubmitControl())
+      ->addCancelButton($done_uri);
+
     if (!$option->getLocked()) {
-      $form
-        ->appendChild(
-          id(new AphrontFormSubmitControl())
-            ->addCancelButton($done_uri)
-            ->setValue(pht('Save Config Entry')));
+      $submit_control->setValue(pht('Save Config Entry'));
     }
 
+    $form->appendChild($submit_control);
+
     $examples = $this->renderExamples($option);
     if ($examples) {
       $form->appendChild(
@@ -151,10 +165,12 @@ final class PhabricatorConfigEditController
           ->setValue($examples));
     }
 
-    $form->appendChild(
-      id(new AphrontFormMarkupControl())
-        ->setLabel(pht('Default'))
-        ->setValue($this->renderDefaults($option)));
+    if (!$option->getHidden()) {
+      $form->appendChild(
+        id(new AphrontFormMarkupControl())
+          ->setLabel(pht('Default'))
+          ->setValue($this->renderDefaults($option)));
+    }
 
     $title = pht('Edit %s', $this->key);
     $short = pht('Edit');
@@ -256,6 +272,20 @@ final class PhabricatorConfigEditController
             break;
         }
         break;
+      case 'class':
+        if (!class_exists($value)) {
+          $e_value = pht('Invalid');
+          $errors[] = pht('Class does not exist.');
+        } else {
+          $base = $option->getBaseClass();
+          if (!is_subclass_of($value, $base)) {
+            $e_value = pht('Invalid');
+            $errors[] = pht('Class is not of valid type.');
+          } else {
+            $set_value = $value;
+          }
+        }
+        break;
       default:
         $json = json_decode($value, true);
         if ($json === null && strtolower($value) != 'null') {
@@ -319,11 +349,26 @@ final class PhabricatorConfigEditController
         $control = id(new AphrontFormSelectControl())
           ->setOptions(
             array(
-              ''      => '(Use Default)',
+              ''      => pht('(Use Default)'),
               'true'  => idx($option->getOptions(), 0),
               'false' => idx($option->getOptions(), 1),
             ));
         break;
+      case 'class':
+        $symbols = id(new PhutilSymbolLoader())
+          ->setType('class')
+          ->setAncestorClass($option->getBaseClass())
+          ->setConcreteOnly(true)
+          ->selectSymbolsWithoutLoading();
+        $names = ipull($symbols, 'name', 'name');
+        sort($names);
+        $names = array(
+          '' => pht('(Use Default)'),
+        ) + $names;
+
+        $control = id(new AphrontFormSelectControl())
+          ->setOptions($names);
+        break;
       case 'list<string>':
         $control = id(new AphrontFormTextAreaControl())
           ->setCaption(pht('Separate values with newlines or commas.'));
diff --git a/src/applications/config/controller/PhabricatorConfigGroupController.php b/src/applications/config/controller/PhabricatorConfigGroupController.php
index def0510ca4..1d5042b2fd 100644
--- a/src/applications/config/controller/PhabricatorConfigGroupController.php
+++ b/src/applications/config/controller/PhabricatorConfigGroupController.php
@@ -67,22 +67,24 @@ final class PhabricatorConfigGroupController
 
     $list = new PhabricatorObjectItemListView();
     foreach ($options as $option) {
-      $current_value = PhabricatorEnv::getEnvConfig($option->getKey());
-      $current_value = $this->prettyPrintJSON($current_value);
-      $current_value = phutil_render_tag(
-        'div',
-        array(
-          'class' => 'config-options-current-value',
-        ),
-        '<span>'.pht('Current Value:').'</span> '.
-        phutil_escape_html($current_value));
-
-
       $item = id(new PhabricatorObjectItemView())
         ->setHeader($option->getKey())
         ->setHref('/config/edit/'.$option->getKey().'/')
-        ->addAttribute(phutil_escape_html($option->getSummary()))
-        ->appendChild($current_value);
+        ->addAttribute(phutil_escape_html($option->getSummary()));
+
+      if (!$option->getHidden()) {
+        $current_value = PhabricatorEnv::getEnvConfig($option->getKey());
+        $current_value = $this->prettyPrintJSON($current_value);
+        $current_value = phutil_render_tag(
+          'div',
+          array(
+            'class' => 'config-options-current-value',
+          ),
+          '<span>'.pht('Current Value:').'</span> '.
+          phutil_escape_html($current_value));
+
+        $item->appendChild($current_value);
+      }
 
       $db_value = idx($db_values, $option->getKey());
       if ($db_value && !$db_value->getIsDeleted()) {
@@ -91,7 +93,9 @@ final class PhabricatorConfigGroupController
         $item->addIcon('edit-grey', pht('Default'));
       }
 
-      if ($option->getLocked()) {
+      if ($option->getHidden()) {
+        $item->addIcon('unpublish', pht('Hidden'));
+      } else if ($option->getLocked()) {
         $item->addIcon('lock', pht('Locked'));
       }
 
diff --git a/src/applications/config/option/PhabricatorApplicationConfigOptions.php b/src/applications/config/option/PhabricatorApplicationConfigOptions.php
index 21e23b782b..9bd6d402db 100644
--- a/src/applications/config/option/PhabricatorApplicationConfigOptions.php
+++ b/src/applications/config/option/PhabricatorApplicationConfigOptions.php
@@ -41,6 +41,21 @@ abstract class PhabricatorApplicationConfigOptions extends Phobject {
               $option->getKey()));
         }
         break;
+      case 'class':
+        $symbols = id(new PhutilSymbolLoader())
+          ->setType('class')
+          ->setAncestorClass($option->getBaseClass())
+          ->setConcreteOnly(true)
+          ->selectSymbolsWithoutLoading();
+        $names = ipull($symbols, 'name', 'name');
+        if (empty($names[$value])) {
+          throw new PhabricatorConfigValidationException(
+            pht(
+              "Option '%s' value must name a class extending '%s'.",
+              $option->getKey(),
+              $option->getBaseClass()));
+        }
+        break;
       case 'list<string>':
         $valid = true;
         if (!is_array($value)) {
diff --git a/src/applications/config/option/PhabricatorConfigOption.php b/src/applications/config/option/PhabricatorConfigOption.php
index 7827626e36..e80a92ac83 100644
--- a/src/applications/config/option/PhabricatorConfigOption.php
+++ b/src/applications/config/option/PhabricatorConfigOption.php
@@ -13,6 +13,39 @@ final class PhabricatorConfigOption
   private $group;
   private $examples;
   private $locked;
+  private $hidden;
+  private $masked;
+  private $baseClass;
+
+  public function setBaseClass($base_class) {
+    $this->baseClass = $base_class;
+    return $this;
+  }
+
+  public function getBaseClass() {
+    return $this->baseClass;
+  }
+
+  public function setMasked($masked) {
+    $this->masked = $masked;
+    return $this;
+  }
+
+  public function getMasked() {
+    if ($this->getHidden()) {
+      return true;
+    }
+    return $this->masked;
+  }
+
+  public function setHidden($hidden) {
+    $this->hidden = $hidden;
+    return $this;
+  }
+
+  public function getHidden() {
+    return $this->hidden;
+  }
 
   public function setLocked($locked) {
     $this->locked = $locked;
@@ -20,6 +53,9 @@ final class PhabricatorConfigOption
   }
 
   public function getLocked() {
+    if ($this->getHidden()) {
+      return true;
+    }
     return $this->locked;
   }
 
diff --git a/src/applications/config/option/PhabricatorCoreConfigOptions.php b/src/applications/config/option/PhabricatorCoreConfigOptions.php
index d8490dcf6d..d00656a27b 100644
--- a/src/applications/config/option/PhabricatorCoreConfigOptions.php
+++ b/src/applications/config/option/PhabricatorCoreConfigOptions.php
@@ -65,19 +65,6 @@ final class PhabricatorCoreConfigOptions
             "and a call to 'Leap Into Action'. If you'd prefer more ".
             "traditional UI strings like 'Submit', you can set this flag to ".
             "disable most of the jokes and easter eggs.")),
-       $this->newOption('storage.default-namespace', 'string', 'phabricator')
-        // NOTE: Lock this, since editing it from the web torpedoes an install.
-        ->setLocked(true)
-        ->setSummary(
-          pht("The namespace that Phabricator databases should use."))
-        ->setDescription(
-          pht(
-            "Phabricator puts databases in a namespace, which defualts to ".
-            "'phabricator' -- for instance, the Differential database is ".
-            "named 'phabricator_differential' by default. You can change ".
-            "this namespace if you want. Normally, you should not do this ".
-            "unless you are developing Phabricator and using namespaces to ".
-            "separate multiple sandbox datasets.")),
        $this->newOption('environment.append-paths', 'list<string>', null)
         ->setSummary(
           pht("These paths get appended to your \$PATH envrionment variable."))
diff --git a/src/applications/config/option/PhabricatorExtendingPhabricatorConfigOptions.php b/src/applications/config/option/PhabricatorExtendingPhabricatorConfigOptions.php
index 235b231ab5..d168b4d240 100644
--- a/src/applications/config/option/PhabricatorExtendingPhabricatorConfigOptions.php
+++ b/src/applications/config/option/PhabricatorExtendingPhabricatorConfigOptions.php
@@ -15,7 +15,7 @@ final class PhabricatorExtendingPhabricatorConfigOptions
     return array(
       $this->newOption('load-libraries', 'list<string>', null)
         ->setSummary(pht("Paths to additional phutil libraries to load."))
-        ->addExample('/srv/our-sekrit-libs/sekrit-phutil', 'Valid Setting'),
+        ->addExample('/srv/our-libs/sekrit-phutil', pht('Valid Setting')),
       $this->newOption('events.listeners', 'list<string>', null)
         ->setSummary(
           pht("Listeners receive callbacks when interesting things occur."))
@@ -25,7 +25,7 @@ final class PhabricatorExtendingPhabricatorConfigOptions
             "listeners, which will receive callbacks when interesting things ".
             "occur. Specify a list of classes which extend ".
             "PhabricatorEventListener here."))
-        ->addExample('MyEventListener', 'Valid Setting'),
+        ->addExample('MyEventListener', pht('Valid Setting')),
       $this->newOption(
         'celerity.resource-path',
         'string',
@@ -36,7 +36,7 @@ final class PhabricatorExtendingPhabricatorConfigOptions
           pht(
             "Path to custom celerity resource map relative to ".
             "'phabricator/src'. See also `scripts/celerity_mapper.php`."))
-        ->addExample('local/my_celerity_map.php', 'Valid Setting'),
+        ->addExample('local/my_celerity_map.php', pht('Valid Setting')),
     );
   }
 
diff --git a/src/applications/config/option/PhabricatorMySQLConfigOptions.php b/src/applications/config/option/PhabricatorMySQLConfigOptions.php
new file mode 100644
index 0000000000..05741f4ba6
--- /dev/null
+++ b/src/applications/config/option/PhabricatorMySQLConfigOptions.php
@@ -0,0 +1,73 @@
+<?php
+
+final class PhabricatorMySQLConfigOptions
+  extends PhabricatorApplicationConfigOptions {
+
+  public function getName() {
+    return pht("MySQL");
+  }
+
+  public function getDescription() {
+    return pht("Database configuration.");
+  }
+
+  public function getOptions() {
+    return array(
+      $this->newOption('mysql.host', 'string', 'localhost')
+        ->setLocked(true)
+        ->setDescription(
+          pht("MySQL database hostname."))
+        ->addExample('localhost', pht('MySQL on this machine'))
+        ->addExample('db.example.com:3300', pht('Nonstandard port')),
+      $this->newOption('mysql.user', 'string', 'root')
+        ->setLocked(true)
+        ->setDescription(
+          pht("MySQL username to use when connecting to the database.")),
+      $this->newOption('mysql.pass', 'string', null)
+        ->setHidden(true)
+        ->setDescription(
+          pht("MySQL password to use when connecting to the database.")),
+      $this->newOption(
+        'mysql.configuration-provider',
+        'class',
+        'DefaultDatabaseConfigurationProvider')
+        ->setLocked(true)
+        ->setBaseClass('DatabaseConfigurationProvider')
+        ->setSummary(
+          pht('Configure database configuration class.'))
+        ->setDescription(
+          pht(
+            "Phabricator chooses which database to connect to through a ".
+            "swappable configuration provider. You almost certainly do not ".
+            "need to change this.")),
+      $this->newOption(
+        'mysql.implementation',
+        'class',
+        'AphrontMySQLDatabaseConnection')
+        ->setLocked(true)
+        ->setBaseClass('AphrontMySQLDatabaseConnectionBase')
+        ->setSummary(
+          pht('Configure database connection class.'))
+        ->setDescription(
+          pht(
+            "Phabricator connects to MySQL through a swappable abstraction ".
+            "layer. You can choose an alternate implementation by setting ".
+            "this option. To provide your own implementation, extend ".
+            "`AphrontMySQLDatabaseConnectionBase`. It is very unlikely that ".
+            "you need to change this.")),
+      $this->newOption('storage.default-namespace', 'string', 'phabricator')
+        ->setLocked(true)
+        ->setSummary(
+          pht("The namespace that Phabricator databases should use."))
+        ->setDescription(
+          pht(
+            "Phabricator puts databases in a namespace, which defaults to ".
+            "'phabricator' -- for instance, the Differential database is ".
+            "named 'phabricator_differential' by default. You can change ".
+            "this namespace if you want. Normally, you should not do this ".
+            "unless you are developing Phabricator and using namespaces to ".
+            "separate multiple sandbox datasets.")),
+    );
+  }
+
+}
diff --git a/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php b/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php
index 13092ca3fc..0158d18b10 100644
--- a/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php
+++ b/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php
@@ -103,7 +103,6 @@ abstract class PhabricatorLiskDAO extends LiskDAO {
       'mysql.configuration-provider',
       array($this, $mode, $namespace));
 
-    $retries = PhabricatorEnv::getEnvConfig('mysql.connection-retries');
     return PhabricatorEnv::newObjectFromConfig(
       'mysql.implementation',
       array(
@@ -112,7 +111,7 @@ abstract class PhabricatorLiskDAO extends LiskDAO {
           'pass'      => $conf->getPassword(),
           'host'      => $conf->getHost(),
           'database'  => $conf->getDatabase(),
-          'retries'   => $retries,
+          'retries'   => 3,
         ),
       ));
   }