diff --git a/src/infrastructure/cluster/PhabricatorDatabaseRef.php b/src/infrastructure/cluster/PhabricatorDatabaseRef.php
index 5a32ef7c11..7dc55427ca 100644
--- a/src/infrastructure/cluster/PhabricatorDatabaseRef.php
+++ b/src/infrastructure/cluster/PhabricatorDatabaseRef.php
@@ -1,731 +1,738 @@
 <?php
 
 final class PhabricatorDatabaseRef
   extends Phobject {
 
   const STATUS_OKAY = 'okay';
   const STATUS_FAIL = 'fail';
   const STATUS_AUTH = 'auth';
   const STATUS_REPLICATION_CLIENT = 'replication-client';
 
   const REPLICATION_OKAY = 'okay';
   const REPLICATION_MASTER_REPLICA = 'master-replica';
   const REPLICATION_REPLICA_NONE = 'replica-none';
   const REPLICATION_SLOW = 'replica-slow';
   const REPLICATION_NOT_REPLICATING = 'not-replicating';
 
   const KEY_HEALTH = 'cluster.db.health';
   const KEY_REFS = 'cluster.db.refs';
   const KEY_INDIVIDUAL = 'cluster.db.individual';
 
   private $host;
   private $port;
   private $user;
   private $pass;
   private $disabled;
   private $isMaster;
   private $isIndividual;
 
   private $connectionLatency;
   private $connectionStatus;
   private $connectionMessage;
+  private $connectionException;
 
   private $replicaStatus;
   private $replicaMessage;
   private $replicaDelay;
 
   private $healthRecord;
   private $didFailToConnect;
 
   private $isDefaultPartition;
   private $applicationMap = array();
   private $masterRef;
   private $replicaRefs = array();
   private $usePersistentConnections;
 
   public function setHost($host) {
     $this->host = $host;
     return $this;
   }
 
   public function getHost() {
     return $this->host;
   }
 
   public function setPort($port) {
     $this->port = $port;
     return $this;
   }
 
   public function getPort() {
     return $this->port;
   }
 
   public function setUser($user) {
     $this->user = $user;
     return $this;
   }
 
   public function getUser() {
     return $this->user;
   }
 
   public function setPass(PhutilOpaqueEnvelope $pass) {
     $this->pass = $pass;
     return $this;
   }
 
   public function getPass() {
     return $this->pass;
   }
 
   public function setIsMaster($is_master) {
     $this->isMaster = $is_master;
     return $this;
   }
 
   public function getIsMaster() {
     return $this->isMaster;
   }
 
   public function setDisabled($disabled) {
     $this->disabled = $disabled;
     return $this;
   }
 
   public function getDisabled() {
     return $this->disabled;
   }
 
   public function setConnectionLatency($connection_latency) {
     $this->connectionLatency = $connection_latency;
     return $this;
   }
 
   public function getConnectionLatency() {
     return $this->connectionLatency;
   }
 
   public function setConnectionStatus($connection_status) {
     $this->connectionStatus = $connection_status;
     return $this;
   }
 
   public function getConnectionStatus() {
     if ($this->connectionStatus === null) {
       throw new PhutilInvalidStateException('queryAll');
     }
 
     return $this->connectionStatus;
   }
 
   public function setConnectionMessage($connection_message) {
     $this->connectionMessage = $connection_message;
     return $this;
   }
 
   public function getConnectionMessage() {
     return $this->connectionMessage;
   }
 
   public function setReplicaStatus($replica_status) {
     $this->replicaStatus = $replica_status;
     return $this;
   }
 
   public function getReplicaStatus() {
     return $this->replicaStatus;
   }
 
   public function setReplicaMessage($replica_message) {
     $this->replicaMessage = $replica_message;
     return $this;
   }
 
   public function getReplicaMessage() {
     return $this->replicaMessage;
   }
 
   public function setReplicaDelay($replica_delay) {
     $this->replicaDelay = $replica_delay;
     return $this;
   }
 
   public function getReplicaDelay() {
     return $this->replicaDelay;
   }
 
   public function setIsIndividual($is_individual) {
     $this->isIndividual = $is_individual;
     return $this;
   }
 
   public function getIsIndividual() {
     return $this->isIndividual;
   }
 
   public function setIsDefaultPartition($is_default_partition) {
     $this->isDefaultPartition = $is_default_partition;
     return $this;
   }
 
   public function getIsDefaultPartition() {
     return $this->isDefaultPartition;
   }
 
   public function setUsePersistentConnections($use_persistent_connections) {
     $this->usePersistentConnections = $use_persistent_connections;
     return $this;
   }
 
   public function getUsePersistentConnections() {
     return $this->usePersistentConnections;
   }
 
   public function setApplicationMap(array $application_map) {
     $this->applicationMap = $application_map;
     return $this;
   }
 
   public function getApplicationMap() {
     return $this->applicationMap;
   }
 
   public function getPartitionStateForCommit() {
     $state = PhabricatorEnv::getEnvConfig('cluster.databases');
     foreach ($state as $key => $value) {
       // Don't store passwords, since we don't care if they differ and
       // users may find it surprising.
       unset($state[$key]['pass']);
     }
 
     return phutil_json_encode($state);
   }
 
   public function setMasterRef(PhabricatorDatabaseRef $master_ref) {
     $this->masterRef = $master_ref;
     return $this;
   }
 
   public function getMasterRef() {
     return $this->masterRef;
   }
 
   public function addReplicaRef(PhabricatorDatabaseRef $replica_ref) {
     $this->replicaRefs[] = $replica_ref;
     return $this;
   }
 
   public function getReplicaRefs() {
     return $this->replicaRefs;
   }
 
 
   public function getRefKey() {
     $host = $this->getHost();
 
     $port = $this->getPort();
     if (strlen($port)) {
       return "{$host}:{$port}";
     }
 
     return $host;
   }
 
   public static function getConnectionStatusMap() {
     return array(
       self::STATUS_OKAY => array(
         'icon' => 'fa-exchange',
         'color' => 'green',
         'label' => pht('Okay'),
       ),
       self::STATUS_FAIL => array(
         'icon' => 'fa-times',
         'color' => 'red',
         'label' => pht('Failed'),
       ),
       self::STATUS_AUTH => array(
         'icon' => 'fa-key',
         'color' => 'red',
         'label' => pht('Invalid Credentials'),
       ),
       self::STATUS_REPLICATION_CLIENT => array(
         'icon' => 'fa-eye-slash',
         'color' => 'yellow',
         'label' => pht('Missing Permission'),
       ),
     );
   }
 
   public static function getReplicaStatusMap() {
     return array(
       self::REPLICATION_OKAY => array(
         'icon' => 'fa-download',
         'color' => 'green',
         'label' => pht('Okay'),
       ),
       self::REPLICATION_MASTER_REPLICA => array(
         'icon' => 'fa-database',
         'color' => 'red',
         'label' => pht('Replicating Master'),
       ),
       self::REPLICATION_REPLICA_NONE => array(
         'icon' => 'fa-download',
         'color' => 'red',
         'label' => pht('Not A Replica'),
       ),
       self::REPLICATION_SLOW => array(
         'icon' => 'fa-hourglass',
         'color' => 'red',
         'label' => pht('Slow Replication'),
       ),
       self::REPLICATION_NOT_REPLICATING => array(
         'icon' => 'fa-exclamation-triangle',
         'color' => 'red',
         'label' => pht('Not Replicating'),
       ),
     );
   }
 
   public static function getClusterRefs() {
     $cache = PhabricatorCaches::getRequestCache();
 
     $refs = $cache->getKey(self::KEY_REFS);
     if (!$refs) {
       $refs = self::newRefs();
       $cache->setKey(self::KEY_REFS, $refs);
     }
 
     return $refs;
   }
 
   public static function getLiveIndividualRef() {
     $cache = PhabricatorCaches::getRequestCache();
 
     $ref = $cache->getKey(self::KEY_INDIVIDUAL);
     if (!$ref) {
       $ref = self::newIndividualRef();
       $cache->setKey(self::KEY_INDIVIDUAL, $ref);
     }
 
     return $ref;
   }
 
   public static function newRefs() {
     $default_port = PhabricatorEnv::getEnvConfig('mysql.port');
     $default_port = nonempty($default_port, 3306);
 
     $default_user = PhabricatorEnv::getEnvConfig('mysql.user');
 
     $default_pass = PhabricatorEnv::getEnvConfig('mysql.pass');
     $default_pass = new PhutilOpaqueEnvelope($default_pass);
 
     $config = PhabricatorEnv::getEnvConfig('cluster.databases');
 
     return id(new PhabricatorDatabaseRefParser())
       ->setDefaultPort($default_port)
       ->setDefaultUser($default_user)
       ->setDefaultPass($default_pass)
       ->newRefs($config);
   }
 
   public static function queryAll() {
     $refs = self::getActiveDatabaseRefs();
     return self::queryRefs($refs);
   }
 
   private static function queryRefs(array $refs) {
     foreach ($refs as $ref) {
       $conn = $ref->newManagementConnection();
 
       $t_start = microtime(true);
       $replica_status = false;
       try {
         $replica_status = queryfx_one($conn, 'SHOW SLAVE STATUS');
         $ref->setConnectionStatus(self::STATUS_OKAY);
       } catch (AphrontAccessDeniedQueryException $ex) {
         $ref->setConnectionStatus(self::STATUS_REPLICATION_CLIENT);
         $ref->setConnectionMessage(
           pht(
             'No permission to run "SHOW SLAVE STATUS". Grant this user '.
             '"REPLICATION CLIENT" permission to allow Phabricator to '.
             'monitor replica health.'));
       } catch (AphrontInvalidCredentialsQueryException $ex) {
         $ref->setConnectionStatus(self::STATUS_AUTH);
         $ref->setConnectionMessage($ex->getMessage());
       } catch (AphrontQueryException $ex) {
         $ref->setConnectionStatus(self::STATUS_FAIL);
 
         $class = get_class($ex);
         $message = $ex->getMessage();
         $ref->setConnectionMessage(
           pht(
             '%s: %s',
             get_class($ex),
             $ex->getMessage()));
       }
       $t_end = microtime(true);
       $ref->setConnectionLatency($t_end - $t_start);
 
       if ($replica_status !== false) {
         $is_replica = (bool)$replica_status;
         if ($ref->getIsMaster() && $is_replica) {
           $ref->setReplicaStatus(self::REPLICATION_MASTER_REPLICA);
           $ref->setReplicaMessage(
             pht(
               'This host has a "master" role, but is replicating data from '.
               'another host ("%s")!',
               idx($replica_status, 'Master_Host')));
         } else if (!$ref->getIsMaster() && !$is_replica) {
           $ref->setReplicaStatus(self::REPLICATION_REPLICA_NONE);
           $ref->setReplicaMessage(
             pht(
               'This host has a "replica" role, but is not replicating data '.
               'from a master (no output from "SHOW SLAVE STATUS").'));
         } else {
           $ref->setReplicaStatus(self::REPLICATION_OKAY);
         }
 
         if ($is_replica) {
           $latency = idx($replica_status, 'Seconds_Behind_Master');
           if (!strlen($latency)) {
             $ref->setReplicaStatus(self::REPLICATION_NOT_REPLICATING);
           } else {
             $latency = (int)$latency;
             $ref->setReplicaDelay($latency);
             if ($latency > 30) {
               $ref->setReplicaStatus(self::REPLICATION_SLOW);
               $ref->setReplicaMessage(
                 pht(
                   'This replica is lagging far behind the master. Data is at '.
                   'risk!'));
             }
           }
         }
       }
     }
 
     return $refs;
   }
 
   public function newManagementConnection() {
     return $this->newConnection(
       array(
         'retries' => 0,
         'timeout' => 2,
       ));
   }
 
   public function newApplicationConnection($database) {
     return $this->newConnection(
       array(
         'database' => $database,
       ));
   }
 
   public function isSevered() {
     // If we only have an individual database, never sever our connection to
     // it, at least for now. It's possible that using the same severing rules
     // might eventually make sense to help alleviate load-related failures,
     // but we should wait for all the cluster stuff to stabilize first.
     if ($this->getIsIndividual()) {
       return false;
     }
 
     if ($this->didFailToConnect) {
       return true;
     }
 
     $record = $this->getHealthRecord();
     $is_healthy = $record->getIsHealthy();
     if (!$is_healthy) {
       return true;
     }
 
     return false;
   }
 
   public function isReachable(AphrontDatabaseConnection $connection) {
     $record = $this->getHealthRecord();
     $should_check = $record->getShouldCheck();
 
     if ($this->isSevered() && !$should_check) {
       return false;
     }
 
+    $this->connectionException = null;
     try {
       $connection->openConnection();
       $reachable = true;
     } catch (AphrontSchemaQueryException $ex) {
       // We get one of these if the database we're trying to select does not
       // exist. In this case, just re-throw the exception. This is expected
       // during first-time setup, when databases like "config" will not exist
       // yet.
       throw $ex;
     } catch (Exception $ex) {
+      $this->connectionException = $ex;
       $reachable = false;
     }
 
     if ($should_check) {
       $record->didHealthCheck($reachable);
     }
 
     if (!$reachable) {
       $this->didFailToConnect = true;
     }
 
     return $reachable;
   }
 
   public function checkHealth() {
     $health = $this->getHealthRecord();
 
     $should_check = $health->getShouldCheck();
     if ($should_check) {
       // This does an implicit health update.
       $connection = $this->newManagementConnection();
       $this->isReachable($connection);
     }
 
     return $this;
   }
 
   private function getHealthRecordCacheKey() {
     $host = $this->getHost();
     $port = $this->getPort();
     $key = self::KEY_HEALTH;
 
     return "{$key}({$host}, {$port})";
   }
 
   public function getHealthRecord() {
     if (!$this->healthRecord) {
       $this->healthRecord = new PhabricatorClusterServiceHealthRecord(
         $this->getHealthRecordCacheKey());
     }
     return $this->healthRecord;
   }
 
+  public function getConnectionException() {
+    return $this->connectionException;
+  }
+
   public static function getActiveDatabaseRefs() {
     $refs = array();
 
     foreach (self::getMasterDatabaseRefs() as $ref) {
       $refs[] = $ref;
     }
 
     foreach (self::getReplicaDatabaseRefs() as $ref) {
       $refs[] = $ref;
     }
 
     return $refs;
   }
 
   public static function getAllMasterDatabaseRefs() {
     $refs = self::getClusterRefs();
 
     if (!$refs) {
       return array(self::getLiveIndividualRef());
     }
 
     $masters = array();
     foreach ($refs as $ref) {
       if ($ref->getIsMaster()) {
         $masters[] = $ref;
       }
     }
 
     return $masters;
   }
 
   public static function getMasterDatabaseRefs() {
     $refs = self::getAllMasterDatabaseRefs();
     return self::getEnabledRefs($refs);
   }
 
   public function isApplicationHost($database) {
     return isset($this->applicationMap[$database]);
   }
 
   public function loadRawMySQLConfigValue($key) {
     $conn = $this->newManagementConnection();
 
     try {
       $value = queryfx_one($conn, 'SELECT @@%Q', $key);
       $value = $value['@@'.$key];
     } catch (AphrontQueryException $ex) {
       $value = null;
     }
 
     return $value;
   }
 
   public static function getMasterDatabaseRefForApplication($application) {
     $masters = self::getMasterDatabaseRefs();
 
     $application_master = null;
     $default_master = null;
     foreach ($masters as $master) {
       if ($master->isApplicationHost($application)) {
         $application_master = $master;
         break;
       }
       if ($master->getIsDefaultPartition()) {
         $default_master = $master;
       }
     }
 
     if ($application_master) {
       $masters = array($application_master);
     } else if ($default_master) {
       $masters = array($default_master);
     } else {
       $masters = array();
     }
 
     $masters = self::getEnabledRefs($masters);
     $master = head($masters);
 
     return $master;
   }
 
   public static function newIndividualRef() {
     $default_user = PhabricatorEnv::getEnvConfig('mysql.user');
     $default_pass = new PhutilOpaqueEnvelope(
       PhabricatorEnv::getEnvConfig('mysql.pass'));
     $default_host = PhabricatorEnv::getEnvConfig('mysql.host');
     $default_port = PhabricatorEnv::getEnvConfig('mysql.port');
 
     return id(new self())
       ->setUser($default_user)
       ->setPass($default_pass)
       ->setHost($default_host)
       ->setPort($default_port)
       ->setIsIndividual(true)
       ->setIsMaster(true)
       ->setIsDefaultPartition(true)
       ->setUsePersistentConnections(false);
   }
 
   public static function getAllReplicaDatabaseRefs() {
     $refs = self::getClusterRefs();
 
     if (!$refs) {
       return array();
     }
 
     $replicas = array();
     foreach ($refs as $ref) {
       if ($ref->getIsMaster()) {
         continue;
       }
 
       $replicas[] = $ref;
     }
 
     return $replicas;
   }
 
   public static function getReplicaDatabaseRefs() {
     $refs = self::getAllReplicaDatabaseRefs();
     return self::getEnabledRefs($refs);
   }
 
   private static function getEnabledRefs(array $refs) {
     foreach ($refs as $key => $ref) {
       if ($ref->getDisabled()) {
         unset($refs[$key]);
       }
     }
     return $refs;
   }
 
   public static function getReplicaDatabaseRefForApplication($application) {
     $replicas = self::getReplicaDatabaseRefs();
 
     $application_replicas = array();
     $default_replicas = array();
     foreach ($replicas as $replica) {
       $master = $replica->getMasterRef();
 
       if ($master->isApplicationHost($application)) {
         $application_replicas[] = $replica;
       }
 
       if ($master->getIsDefaultPartition()) {
         $default_replicas[] = $replica;
       }
     }
 
     if ($application_replicas) {
       $replicas = $application_replicas;
     } else {
       $replicas = $default_replicas;
     }
 
     $replicas = self::getEnabledRefs($replicas);
 
     // TODO: We may have multiple replicas to choose from, and could make
     // more of an effort to pick the "best" one here instead of always
     // picking the first one. Once we've picked one, we should try to use
     // the same replica for the rest of the request, though.
 
     return head($replicas);
   }
 
   private function newConnection(array $options) {
     // If we believe the database is unhealthy, don't spend as much time
     // trying to connect to it, since it's likely to continue to fail and
     // hammering it can only make the problem worse.
     $record = $this->getHealthRecord();
     if ($record->getIsHealthy()) {
       $default_retries = 3;
       $default_timeout = 10;
     } else {
       $default_retries = 0;
       $default_timeout = 2;
     }
 
     $spec = $options + array(
       'user' => $this->getUser(),
       'pass' => $this->getPass(),
       'host' => $this->getHost(),
       'port' => $this->getPort(),
       'database' => null,
       'retries' => $default_retries,
       'timeout' => $default_timeout,
       'persistent' => $this->getUsePersistentConnections(),
     );
 
     $is_cli = (php_sapi_name() == 'cli');
 
     $use_persistent = false;
     if (!empty($spec['persistent']) && !$is_cli) {
       $use_persistent = true;
     }
     unset($spec['persistent']);
 
     $connection = self::newRawConnection($spec);
 
     // If configured, use persistent connections. See T11672 for details.
     if ($use_persistent) {
       $connection->setPersistent($use_persistent);
     }
 
     // Unless this is a script running from the CLI, prevent any query from
     // running for more than 30 seconds. See T10849 for details.
     if (!$is_cli) {
       $connection->setQueryTimeout(30);
     }
 
     return $connection;
   }
 
   public static function newRawConnection(array $options) {
     if (extension_loaded('mysqli')) {
       return new AphrontMySQLiDatabaseConnection($options);
     } else {
       return new AphrontMySQLDatabaseConnection($options);
     }
   }
 
 }
diff --git a/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php b/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php
index 743ca9b759..b3b324e951 100644
--- a/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php
+++ b/src/infrastructure/storage/lisk/PhabricatorLiskDAO.php
@@ -1,319 +1,332 @@
 <?php
 
 /**
  * @task config Configuring Storage
  */
 abstract class PhabricatorLiskDAO extends LiskDAO {
 
   private static $namespaceStack = array();
 
   const ATTACHABLE = '<attachable>';
   const CONFIG_APPLICATION_SERIALIZERS = 'phabricator/serializers';
 
 /* -(  Configuring Storage  )------------------------------------------------ */
 
   /**
    * @task config
    */
   public static function pushStorageNamespace($namespace) {
     self::$namespaceStack[] = $namespace;
   }
 
   /**
    * @task config
    */
   public static function popStorageNamespace() {
     array_pop(self::$namespaceStack);
   }
 
   /**
    * @task config
    */
   public static function getDefaultStorageNamespace() {
     return PhabricatorEnv::getEnvConfig('storage.default-namespace');
   }
 
   /**
    * @task config
    */
   public static function getStorageNamespace() {
     $namespace = end(self::$namespaceStack);
     if (!strlen($namespace)) {
       $namespace = self::getDefaultStorageNamespace();
     }
     if (!strlen($namespace)) {
       throw new Exception(pht('No storage namespace configured!'));
     }
     return $namespace;
   }
 
   /**
    * @task config
    */
   protected function establishLiveConnection($mode) {
     $namespace = self::getStorageNamespace();
     $database = $namespace.'_'.$this->getApplicationName();
 
     $is_readonly = PhabricatorEnv::isReadOnly();
 
     if ($is_readonly && ($mode != 'r')) {
       $this->raiseImproperWrite($database);
     }
 
     $connection = $this->newClusterConnection(
       $this->getApplicationName(),
       $database,
       $mode);
 
     // TODO: This should be testing if the mode is "r", but that would probably
     // break a lot of things. Perform a more narrow test for readonly mode
     // until we have greater certainty that this works correctly most of the
     // time.
     if ($is_readonly) {
       $connection->setReadOnly(true);
     }
 
     return $connection;
   }
 
   private function newClusterConnection($application, $database, $mode) {
     $master = PhabricatorDatabaseRef::getMasterDatabaseRefForApplication(
       $application);
 
+    $master_exception = null;
+
     if ($master && !$master->isSevered()) {
       $connection = $master->newApplicationConnection($database);
       if ($master->isReachable($connection)) {
         return $connection;
       } else {
         if ($mode == 'w') {
           $this->raiseImpossibleWrite($database);
         }
         PhabricatorEnv::setReadOnly(
           true,
           PhabricatorEnv::READONLY_UNREACHABLE);
+
+        $master_exception = $master->getConnectionException();
       }
     }
 
     $replica = PhabricatorDatabaseRef::getReplicaDatabaseRefForApplication(
       $application);
     if ($replica) {
       $connection = $replica->newApplicationConnection($database);
       $connection->setReadOnly(true);
       if ($replica->isReachable($connection)) {
         return $connection;
       }
     }
 
     if (!$master && !$replica) {
       $this->raiseUnconfigured($database);
     }
 
-    $this->raiseUnreachable($database);
+    $this->raiseUnreachable($database, $master_exception);
   }
 
   private function raiseImproperWrite($database) {
     throw new PhabricatorClusterImproperWriteException(
       pht(
         'Unable to establish a write-mode connection (to application '.
         'database "%s") because Phabricator is in read-only mode. Whatever '.
         'you are trying to do does not function correctly in read-only mode.',
         $database));
   }
 
   private function raiseImpossibleWrite($database) {
     throw new PhabricatorClusterImpossibleWriteException(
       pht(
         'Unable to connect to master database ("%s"). This is a severe '.
         'failure; your request did not complete.',
         $database));
   }
 
   private function raiseUnconfigured($database) {
     throw new Exception(
       pht(
         'Unable to establish a connection to any database host '.
         '(while trying "%s"). No masters or replicas are configured.',
         $database));
   }
 
-  private function raiseUnreachable($database) {
-    throw new PhabricatorClusterStrandedException(
-      pht(
-        'Unable to establish a connection to any database host '.
-        '(while trying "%s"). All masters and replicas are completely '.
-        'unreachable.',
-        $database));
+  private function raiseUnreachable($database, Exception $proxy = null) {
+    $message = pht(
+      'Unable to establish a connection to any database host '.
+      '(while trying "%s"). All masters and replicas are completely '.
+      'unreachable.',
+      $database);
+
+    if ($proxy) {
+      $proxy_message = pht(
+        '%s: %s',
+        get_class($proxy),
+        $proxy->getMessage());
+      $message = $message."\n\n".$proxy_message;
+    }
+
+    throw new PhabricatorClusterStrandedException($message);
   }
 
 
   /**
    * @task config
    */
   public function getTableName() {
     $str = 'phabricator';
     $len = strlen($str);
 
     $class = strtolower(get_class($this));
     if (!strncmp($class, $str, $len)) {
       $class = substr($class, $len);
     }
     $app = $this->getApplicationName();
     if (!strncmp($class, $app, strlen($app))) {
       $class = substr($class, strlen($app));
     }
 
     if (strlen($class)) {
       return $app.'_'.$class;
     } else {
       return $app;
     }
   }
 
   /**
    * @task config
    */
   abstract public function getApplicationName();
 
   protected function getConnectionNamespace() {
     return self::getStorageNamespace().'_'.$this->getApplicationName();
   }
 
 
   /**
    * Break a list of escaped SQL statement fragments (e.g., VALUES lists for
    * INSERT, previously built with @{function:qsprintf}) into chunks which will
    * fit under the MySQL 'max_allowed_packet' limit.
    *
    * Chunks are glued together with `$glue`, by default ", ".
    *
    * If a statement is too large to fit within the limit, it is broken into
    * its own chunk (but might fail when the query executes).
    */
   public static function chunkSQL(
     array $fragments,
     $glue = ', ',
     $limit = null) {
 
     if ($limit === null) {
       // NOTE: Hard-code this at 1MB for now, minus a 10% safety buffer.
       // Eventually we could query MySQL or let the user configure it.
       $limit = (int)((1024 * 1024) * 0.90);
     }
 
     $result = array();
 
     $chunk = array();
     $len = 0;
     $glue_len = strlen($glue);
     foreach ($fragments as $fragment) {
       $this_len = strlen($fragment);
 
       if ($chunk) {
         // Chunks after the first also imply glue.
         $this_len += $glue_len;
       }
 
       if ($len + $this_len <= $limit) {
         $len += $this_len;
         $chunk[] = $fragment;
       } else {
         if ($chunk) {
           $result[] = $chunk;
         }
         $len = strlen($fragment);
         $chunk = array($fragment);
       }
     }
 
     if ($chunk) {
       $result[] = $chunk;
     }
 
     foreach ($result as $key => $fragment_list) {
       $result[$key] = implode($glue, $fragment_list);
     }
 
     return $result;
   }
 
   protected function assertAttached($property) {
     if ($property === self::ATTACHABLE) {
       throw new PhabricatorDataNotAttachedException($this);
     }
     return $property;
   }
 
   protected function assertAttachedKey($value, $key) {
     $this->assertAttached($value);
     if (!array_key_exists($key, $value)) {
       throw new PhabricatorDataNotAttachedException($this);
     }
     return $value[$key];
   }
 
   protected function detectEncodingForStorage($string) {
     return phutil_is_utf8($string) ? 'utf8' : null;
   }
 
   protected function getUTF8StringFromStorage($string, $encoding) {
     if ($encoding == 'utf8') {
       return $string;
     }
 
     if (function_exists('mb_detect_encoding')) {
       if (strlen($encoding)) {
         $try_encodings = array(
           $encoding,
         );
       } else {
         // TODO: This is pretty much a guess, and probably needs to be
         // configurable in the long run.
         $try_encodings = array(
           'JIS',
           'EUC-JP',
           'SJIS',
           'ISO-8859-1',
         );
       }
 
       $guess = mb_detect_encoding($string, $try_encodings);
       if ($guess) {
         return mb_convert_encoding($string, 'UTF-8', $guess);
       }
     }
 
     return phutil_utf8ize($string);
   }
 
   protected function willReadData(array &$data) {
     parent::willReadData($data);
 
     static $custom;
     if ($custom === null) {
       $custom = $this->getConfigOption(self::CONFIG_APPLICATION_SERIALIZERS);
     }
 
     if ($custom) {
       foreach ($custom as $key => $serializer) {
         $data[$key] = $serializer->willReadValue($data[$key]);
       }
     }
   }
 
   protected function willWriteData(array &$data) {
     static $custom;
     if ($custom === null) {
       $custom = $this->getConfigOption(self::CONFIG_APPLICATION_SERIALIZERS);
     }
 
     if ($custom) {
       foreach ($custom as $key => $serializer) {
         $data[$key] = $serializer->willWriteValue($data[$key]);
       }
     }
 
     parent::willWriteData($data);
   }
 
 
 }