diff --git a/resources/sql/autopatches/20170419.thread.03.touched.sql b/resources/sql/autopatches/20170419.thread.03.touched.sql
new file mode 100644
index 0000000000..f6fee00272
--- /dev/null
+++ b/resources/sql/autopatches/20170419.thread.03.touched.sql
@@ -0,0 +1,2 @@
+ALTER TABLE {$NAMESPACE}_conpherence.conpherence_participant
+  DROP dateTouched;
diff --git a/src/applications/conpherence/editor/ConpherenceEditor.php b/src/applications/conpherence/editor/ConpherenceEditor.php
index 6668b3324f..59d854cdc3 100644
--- a/src/applications/conpherence/editor/ConpherenceEditor.php
+++ b/src/applications/conpherence/editor/ConpherenceEditor.php
@@ -1,512 +1,508 @@
 <?php
 
 final class ConpherenceEditor extends PhabricatorApplicationTransactionEditor {
 
   const ERROR_EMPTY_PARTICIPANTS = 'error-empty-participants';
   const ERROR_EMPTY_MESSAGE = 'error-empty-message';
 
   public function getEditorApplicationClass() {
     return 'PhabricatorConpherenceApplication';
   }
 
   public function getEditorObjectsDescription() {
     return pht('Conpherence Rooms');
   }
 
   public static function createThread(
     PhabricatorUser $creator,
     array $participant_phids,
     $title,
     $message,
     PhabricatorContentSource $source,
     $topic) {
 
     $conpherence = ConpherenceThread::initializeNewRoom($creator);
     $errors = array();
     if (empty($participant_phids)) {
       $errors[] = self::ERROR_EMPTY_PARTICIPANTS;
     } else {
       $participant_phids[] = $creator->getPHID();
       $participant_phids = array_unique($participant_phids);
     }
 
     if (empty($message)) {
       $errors[] = self::ERROR_EMPTY_MESSAGE;
     }
 
     if (!$errors) {
       $xactions = array();
       $xactions[] = id(new ConpherenceTransaction())
         ->setTransactionType(ConpherenceTransaction::TYPE_PARTICIPANTS)
         ->setNewValue(array('+' => $participant_phids));
       if ($title) {
         $xactions[] = id(new ConpherenceTransaction())
           ->setTransactionType(
             ConpherenceThreadTitleTransaction::TRANSACTIONTYPE)
           ->setNewValue($title);
       }
       if (strlen($topic)) {
         $xactions[] = id(new ConpherenceTransaction())
           ->setTransactionType(
             ConpherenceThreadTopicTransaction::TRANSACTIONTYPE)
           ->setNewValue($topic);
       }
 
       $xactions[] = id(new ConpherenceTransaction())
         ->setTransactionType(PhabricatorTransactions::TYPE_COMMENT)
         ->attachComment(
           id(new ConpherenceTransactionComment())
           ->setContent($message)
           ->setConpherencePHID($conpherence->getPHID()));
 
       id(new ConpherenceEditor())
         ->setActor($creator)
         ->setContentSource($source)
         ->setContinueOnNoEffect(true)
         ->applyTransactions($conpherence, $xactions);
     }
 
     return array($errors, $conpherence);
   }
 
   public function generateTransactionsFromText(
     PhabricatorUser $viewer,
     ConpherenceThread $conpherence,
     $text) {
 
     $xactions = array();
     $xactions[] = id(new ConpherenceTransaction())
       ->setTransactionType(PhabricatorTransactions::TYPE_COMMENT)
       ->attachComment(
         id(new ConpherenceTransactionComment())
         ->setContent($text)
         ->setConpherencePHID($conpherence->getPHID()));
     return $xactions;
   }
 
   public function getTransactionTypes() {
     $types = parent::getTransactionTypes();
 
     $types[] = ConpherenceTransaction::TYPE_PARTICIPANTS;
 
     $types[] = PhabricatorTransactions::TYPE_COMMENT;
     $types[] = PhabricatorTransactions::TYPE_VIEW_POLICY;
     $types[] = PhabricatorTransactions::TYPE_EDIT_POLICY;
 
     return $types;
   }
 
   public function getCreateObjectTitle($author, $object) {
     return pht('%s created this room.', $author);
   }
 
   protected function getCustomTransactionOldValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case ConpherenceTransaction::TYPE_PARTICIPANTS:
         if ($this->getIsNewObject()) {
           return array();
         }
         return $object->getParticipantPHIDs();
     }
   }
 
   protected function getCustomTransactionNewValue(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case ConpherenceTransaction::TYPE_PARTICIPANTS:
         return $this->getPHIDTransactionNewValue($xaction);
     }
   }
 
   /**
    * We really only need a read lock if we have a comment. In that case, we
    * must update the messagesCount field on the conpherence and
    * seenMessagesCount(s) for the participant(s).
    */
   protected function shouldReadLock(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     $lock = false;
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         $lock =  true;
         break;
     }
 
     return $lock;
   }
 
   /**
    * We need to apply initial effects IFF the conpherence is new. We must
    * save the conpherence first thing to make sure we have an id and a phid, as
    * well as create the initial set of participants so that we pass policy
    * checks.
    */
   protected function shouldApplyInitialEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     return $this->getIsNewObject();
   }
 
   protected function applyInitialEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $object->save();
 
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case ConpherenceTransaction::TYPE_PARTICIPANTS:
           // Since this is a new ConpherenceThread, we have to create the
           // participation data asap to pass policy checks. For existing
           // ConpherenceThreads, the existing participation is correct
           // at this stage. Note that later in applyCustomExternalTransaction
           // this participation data will be updated.
           $participants = array();
           $phids = $this->getPHIDTransactionNewValue($xaction, array());
           foreach ($phids as $phid) {
             if ($phid == $this->getActor()->getPHID()) {
               $message_count = 1;
             } else {
               $message_count = 0;
             }
             $participants[$phid] =
               id(new ConpherenceParticipant())
               ->setConpherencePHID($object->getPHID())
               ->setParticipantPHID($phid)
-              ->setDateTouched(time())
               ->setSeenMessageCount($message_count)
               ->save();
             $object->attachParticipants($participants);
           }
           break;
       }
     }
   }
 
   protected function applyCustomInternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case ConpherenceTransaction::TYPE_PARTICIPANTS:
         if (!$this->getIsNewObject()) {}
         break;
     }
 
   }
 
   protected function applyBuiltinInternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case PhabricatorTransactions::TYPE_COMMENT:
         $object->setMessageCount((int)$object->getMessageCount() + 1);
         break;
     }
 
     return parent::applyBuiltinInternalTransaction($object, $xaction);
   }
 
   protected function applyCustomExternalTransaction(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     switch ($xaction->getTransactionType()) {
       case ConpherenceTransaction::TYPE_PARTICIPANTS:
         if ($this->getIsNewObject()) {
           continue;
         }
         $participants = $object->getParticipants();
 
         $old_map = array_fuse($xaction->getOldValue());
         $new_map = array_fuse($xaction->getNewValue());
 
         $remove = array_keys(array_diff_key($old_map, $new_map));
         foreach ($remove as $phid) {
           $remove_participant = $participants[$phid];
           $remove_participant->delete();
           unset($participants[$phid]);
         }
 
         $add = array_keys(array_diff_key($new_map, $old_map));
         foreach ($add as $phid) {
           if ($phid == $this->getActor()->getPHID()) {
             $message_count = $object->getMessageCount();
           } else {
             $message_count = 0;
           }
           $participants[$phid] =
             id(new ConpherenceParticipant())
             ->setConpherencePHID($object->getPHID())
             ->setParticipantPHID($phid)
-            ->setDateTouched(time())
             ->setSeenMessageCount($message_count)
             ->save();
         }
         $object->attachParticipants($participants);
         break;
     }
   }
 
   protected function applyFinalEffects(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     if (!$xactions) {
       return $xactions;
     }
 
     $message_count = 0;
     foreach ($xactions as $xaction) {
       switch ($xaction->getTransactionType()) {
         case PhabricatorTransactions::TYPE_COMMENT:
           $message_count++;
 
           // update everyone's participation status on a message -only-
           $xaction_phid = $xaction->getPHID();
           $participants = $object->getParticipants();
           $user = $this->getActor();
           $time = time();
           foreach ($participants as $phid => $participant) {
             if ($phid != $user->getPHID()) {
               if ($participant->isUpToDate($object)) {
                 $participant->setSeenMessageCount(
                   $object->getMessageCount() - $message_count);
               }
-              $participant->setDateTouched($time);
             } else {
               $participant->setSeenMessageCount($object->getMessageCount());
-              $participant->setDateTouched($time);
             }
             $participant->save();
           }
 
           PhabricatorUserCache::clearCaches(
             PhabricatorUserMessageCountCacheType::KEY_COUNT,
             array_keys($participants));
 
           break;
       }
     }
 
     if ($xactions) {
       $data = array(
         'type'        => 'message',
         'threadPHID'  => $object->getPHID(),
         'messageID'   => last($xactions)->getID(),
         'subscribers' => array($object->getPHID()),
       );
 
       PhabricatorNotificationClient::tryToPostMessage($data);
     }
 
     return $xactions;
   }
 
   protected function requireCapabilities(
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
     parent::requireCapabilities($object, $xaction);
 
     switch ($xaction->getTransactionType()) {
       case ConpherenceTransaction::TYPE_PARTICIPANTS:
         $old_map = array_fuse($xaction->getOldValue());
         $new_map = array_fuse($xaction->getNewValue());
 
         $add = array_keys(array_diff_key($new_map, $old_map));
         $rem = array_keys(array_diff_key($old_map, $new_map));
 
         $actor_phid = $this->getActingAsPHID();
 
         $is_join = (($add === array($actor_phid)) && !$rem);
         $is_leave = (($rem === array($actor_phid)) && !$add);
 
         if ($is_join) {
           // Anyone can join a thread they can see.
         } else if ($is_leave) {
           // Anyone can leave a thread.
         } else {
           // You need CAN_EDIT to add or remove participants. For additional
           // discussion, see D17696 and T4411.
           PhabricatorPolicyFilter::requireCapability(
             $this->requireActor(),
             $object,
             PhabricatorPolicyCapability::CAN_EDIT);
         }
 
         break;
       case ConpherenceThreadTitleTransaction::TRANSACTIONTYPE:
       case ConpherenceThreadTopicTransaction::TRANSACTIONTYPE:
         PhabricatorPolicyFilter::requireCapability(
           $this->requireActor(),
           $object,
           PhabricatorPolicyCapability::CAN_EDIT);
         break;
     }
   }
 
   protected function mergeTransactions(
     PhabricatorApplicationTransaction $u,
     PhabricatorApplicationTransaction $v) {
 
     $type = $u->getTransactionType();
     switch ($type) {
       case ConpherenceTransaction::TYPE_PARTICIPANTS:
         return $this->mergePHIDOrEdgeTransactions($u, $v);
     }
 
     return parent::mergeTransactions($u, $v);
   }
 
   protected function shouldSendMail(
     PhabricatorLiskDAO $object,
     array $xactions) {
     return true;
   }
 
   protected function buildReplyHandler(PhabricatorLiskDAO $object) {
     return id(new ConpherenceReplyHandler())
       ->setActor($this->getActor())
       ->setMailReceiver($object);
   }
 
   protected function buildMailTemplate(PhabricatorLiskDAO $object) {
     $id = $object->getID();
     $title = $object->getTitle();
     if (!$title) {
       $title = pht(
         '%s sent you a message.',
         $this->getActor()->getUserName());
     }
     $phid = $object->getPHID();
 
     return id(new PhabricatorMetaMTAMail())
       ->setSubject("Z{$id}: {$title}")
       ->addHeader('Thread-Topic', "Z{$id}: {$phid}");
   }
 
   protected function getMailTo(PhabricatorLiskDAO $object) {
     $to_phids = array();
 
     $participants = $object->getParticipants();
     if (!$participants) {
       return $to_phids;
     }
 
     $participant_phids = mpull($participants, 'getParticipantPHID');
 
     $users = id(new PhabricatorPeopleQuery())
       ->setViewer(PhabricatorUser::getOmnipotentUser())
       ->withPHIDs($participant_phids)
       ->needUserSettings(true)
       ->execute();
     $users = mpull($users, null, 'getPHID');
 
     $notification_key = PhabricatorConpherenceNotificationsSetting::SETTINGKEY;
     $notification_email =
       PhabricatorConpherenceNotificationsSetting::VALUE_CONPHERENCE_EMAIL;
 
     foreach ($participants as $phid => $participant) {
       $user = idx($users, $phid);
       if ($user) {
         $default = $user->getUserSetting($notification_key);
       } else {
         $default = $notification_email;
       }
 
       $settings = $participant->getSettings();
       $notifications = idx($settings, 'notifications', $default);
 
       if ($notifications == $notification_email) {
         $to_phids[] = $phid;
       }
     }
 
     return $to_phids;
   }
 
   protected function getMailCC(PhabricatorLiskDAO $object) {
     return array();
   }
 
   protected function buildMailBody(
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $body = parent::buildMailBody($object, $xactions);
     $body->addLinkSection(
       pht('CONPHERENCE DETAIL'),
       PhabricatorEnv::getProductionURI('/'.$object->getMonogram()));
 
     return $body;
   }
 
   protected function addEmailPreferenceSectionToMailBody(
     PhabricatorMetaMTAMailBody $body,
     PhabricatorLiskDAO $object,
     array $xactions) {
 
     $href = PhabricatorEnv::getProductionURI(
       '/'.$object->getMonogram().'?settings');
     $label = pht('EMAIL PREFERENCES FOR THIS ROOM');
     $body->addLinkSection($label, $href);
   }
 
   protected function getMailSubjectPrefix() {
     return PhabricatorEnv::getEnvConfig('metamta.conpherence.subject-prefix');
   }
 
   protected function supportsSearch() {
     return true;
   }
 
   protected function validateTransaction(
     PhabricatorLiskDAO $object,
     $type,
     array $xactions) {
 
     $errors = parent::validateTransaction($object, $type, $xactions);
 
     switch ($type) {
       case ConpherenceTransaction::TYPE_PARTICIPANTS:
         foreach ($xactions as $xaction) {
           $new_phids = $this->getPHIDTransactionNewValue($xaction, array());
           $old_phids = nonempty($object->getParticipantPHIDs(), array());
           $phids = array_diff($new_phids, $old_phids);
 
           if (!$phids) {
             continue;
           }
 
           $users = id(new PhabricatorPeopleQuery())
             ->setViewer($this->requireActor())
             ->withPHIDs($phids)
             ->execute();
           $users = mpull($users, null, 'getPHID');
           foreach ($phids as $phid) {
             if (isset($users[$phid])) {
               continue;
             }
             $errors[] = new PhabricatorApplicationTransactionValidationError(
               $type,
               pht('Invalid'),
               pht('New room participant "%s" is not a valid user.', $phid),
               $xaction);
           }
         }
         break;
     }
 
     return $errors;
   }
 }
diff --git a/src/applications/conpherence/query/ConpherenceParticipantQuery.php b/src/applications/conpherence/query/ConpherenceParticipantQuery.php
index bb879be4e4..e538ded2c2 100644
--- a/src/applications/conpherence/query/ConpherenceParticipantQuery.php
+++ b/src/applications/conpherence/query/ConpherenceParticipantQuery.php
@@ -1,128 +1,65 @@
 <?php
 
-/**
- * Query class that answers these questions:
- *
- * - Q: What are the conpherences to show when I land on /conpherence/ ?
- * - A:
- *
- *     id(new ConpherenceParticipantQuery())
- *     ->withParticipantPHIDs(array($my_phid))
- *     ->execute();
- *
- * - Q: What are the next set of conpherences as I scroll up (more recent) or
- *      down (less recent) this list of conpherences?
- * - A:
- *
- *     id(new ConpherenceParticipantQuery())
- *     ->withParticipantPHIDs(array($my_phid))
- *     ->withParticipantCursor($top_participant)
- *     ->setOrder(ConpherenceParticipantQuery::ORDER_NEWER)
- *     ->execute();
- *
- *     -or-
- *
- *     id(new ConpherenceParticipantQuery())
- *     ->withParticipantPHIDs(array($my_phid))
- *     ->withParticipantCursor($bottom_participant)
- *     ->setOrder(ConpherenceParticipantQuery::ORDER_OLDER)
- *     ->execute();
- *
- * For counts of read, un-read, or all conpherences by participant, see
- * @{class:ConpherenceParticipantCountQuery}.
- */
 final class ConpherenceParticipantQuery extends PhabricatorOffsetPagedQuery {
 
-  const LIMIT = 100;
-  const ORDER_NEWER = 'newer';
-  const ORDER_OLDER = 'older';
-
   private $participantPHIDs;
-  private $participantCursor;
-  private $order = self::ORDER_OLDER;
 
   public function withParticipantPHIDs(array $phids) {
     $this->participantPHIDs = $phids;
     return $this;
   }
 
-  public function withParticipantCursor(ConpherenceParticipant $participant) {
-    $this->participantCursor = $participant;
-    return $this;
-  }
-
-  public function setOrder($order) {
-    $this->order = $order;
-    return $this;
-  }
-
   public function execute() {
     $table = new ConpherenceParticipant();
-    $conn_r = $table->establishConnection('r');
+    $thread = new ConpherenceThread();
+
+    $conn = $table->establishConnection('r');
 
     $data = queryfx_all(
-      $conn_r,
-      'SELECT * FROM %T participant %Q %Q %Q',
+      $conn,
+      'SELECT * FROM %T participant JOIN %T thread
+        ON participant.conpherencePHID = thread.phid %Q %Q %Q',
       $table->getTableName(),
-      $this->buildWhereClause($conn_r),
-      $this->buildOrderClause($conn_r),
-      $this->buildLimitClause($conn_r));
+      $thread->getTableName(),
+      $this->buildWhereClause($conn),
+      $this->buildOrderClause($conn),
+      $this->buildLimitClause($conn));
 
     $participants = $table->loadAllFromArray($data);
 
-    $participants = mpull($participants, null, 'getConpherencePHID');
-
-    if ($this->order == self::ORDER_NEWER) {
-      $participants = array_reverse($participants);
+    // TODO: Fix this, it's bogus.
+    if ('garbage') {
+      if (count($this->participantPHIDs) !== 1) {
+        throw new Exception(
+          pht(
+            'This query only works when querying for exactly one participant '.
+            'PHID!'));
+      }
+      // This will throw results away if we aren't doing a query for exactly
+      // one participant PHID.
+      $participants = mpull($participants, null, 'getConpherencePHID');
     }
 
     return $participants;
   }
 
-  protected function buildWhereClause(AphrontDatabaseConnection $conn_r) {
+  protected function buildWhereClause(AphrontDatabaseConnection $conn) {
     $where = array();
 
-    if ($this->participantPHIDs) {
+    if ($this->participantPHIDs !== null) {
       $where[] = qsprintf(
-        $conn_r,
+        $conn,
         'participantPHID IN (%Ls)',
         $this->participantPHIDs);
     }
 
-    if ($this->participantCursor) {
-      $date_touched = $this->participantCursor->getDateTouched();
-      $id = $this->participantCursor->getID();
-      if ($this->order == self::ORDER_OLDER) {
-        $compare_date = '<';
-        $compare_id = '<=';
-      } else {
-        $compare_date = '>';
-        $compare_id = '>=';
-      }
-      $where[] = qsprintf(
-        $conn_r,
-        '(dateTouched %Q %d OR (dateTouched = %d AND id %Q %d))',
-        $compare_date,
-        $date_touched,
-        $date_touched,
-        $compare_id,
-        $id);
-    }
-
     return $this->formatWhereClause($where);
   }
 
-  private function buildOrderClause(AphrontDatabaseConnection $conn_r) {
-    $order_word = ($this->order == self::ORDER_OLDER) ? 'DESC' : 'ASC';
-    // if these are different direction we won't get as efficient a query
-    // see http://dev.mysql.com/doc/refman/5.5/en/order-by-optimization.html
-    $order = qsprintf(
-      $conn_r,
-      'ORDER BY dateTouched %Q, id %Q',
-      $order_word,
-      $order_word);
-
-    return $order;
+  private function buildOrderClause(AphrontDatabaseConnection $conn) {
+    return qsprintf(
+      $conn,
+      'ORDER BY thread.dateModified DESC, thread.id DESC, participant.id DESC');
   }
 
 }
diff --git a/src/applications/conpherence/storage/ConpherenceParticipant.php b/src/applications/conpherence/storage/ConpherenceParticipant.php
index cb4f7f401d..1c4178c2dc 100644
--- a/src/applications/conpherence/storage/ConpherenceParticipant.php
+++ b/src/applications/conpherence/storage/ConpherenceParticipant.php
@@ -1,59 +1,54 @@
 <?php
 
 final class ConpherenceParticipant extends ConpherenceDAO {
 
   protected $participantPHID;
   protected $conpherencePHID;
   protected $seenMessageCount;
-  protected $dateTouched;
   protected $settings = array();
 
   protected function getConfiguration() {
     return array(
       self::CONFIG_SERIALIZATION => array(
         'settings' => self::SERIALIZATION_JSON,
       ),
       self::CONFIG_COLUMN_SCHEMA => array(
-        'dateTouched' => 'epoch',
         'seenMessageCount' => 'uint64',
       ),
       self::CONFIG_KEY_SCHEMA => array(
         'conpherencePHID' => array(
           'columns' => array('conpherencePHID', 'participantPHID'),
           'unique' => true,
         ),
-        'participationIndex' => array(
-          'columns' => array('participantPHID', 'dateTouched', 'id'),
-        ),
         'key_thread' => array(
           'columns' => array('participantPHID', 'conpherencePHID'),
         ),
       ),
     ) + parent::getConfiguration();
   }
 
   public function getSettings() {
     return nonempty($this->settings, array());
   }
 
   public function markUpToDate(
     ConpherenceThread $conpherence,
     ConpherenceTransaction $xaction) {
 
     if (!$this->isUpToDate($conpherence)) {
       $this->setSeenMessageCount($conpherence->getMessageCount());
       $this->save();
 
       PhabricatorUserCache::clearCache(
         PhabricatorUserMessageCountCacheType::KEY_COUNT,
         $this->getParticipantPHID());
     }
 
     return $this;
   }
 
   public function isUpToDate(ConpherenceThread $conpherence) {
     return ($this->getSeenMessageCount() == $conpherence->getMessageCount());
   }
 
 }