protected function loadPage()
 {
     $table = new PhabricatorCountdown();
     $conn_r = $table->establishConnection('r');
     $data = queryfx_all($conn_r, 'SELECT * FROM %T %Q %Q %Q', $table->getTableName(), $this->buildWhereClause($conn_r), $this->buildOrderClause($conn_r), $this->buildLimitClause($conn_r));
     $countdowns = $table->loadAllFromArray($data);
     return $countdowns;
 }
<?php

$table = new PhabricatorCountdown();
$conn_w = $table->establishConnection('w');
$iterator = new LiskMigrationIterator($table);
foreach ($iterator as $countdown) {
    $id = $countdown->getID();
    echo pht('Adding mail key for countdown %d...', $id);
    echo "\n";
    queryfx($conn_w, 'UPDATE %T SET mailKey = %s WHERE id = %d', $table->getTableName(), Filesystem::readRandomCharacters(20), $id);
}