protected function loadPage()
 {
     $table = new DifferentialDiff();
     $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));
     return $table->loadAllFromArray($data);
 }
<?php

$diff_table = new DifferentialDiff();
$conn_w = $diff_table->establishConnection('w');
$size = 1000;
$row_iter = id(new LiskMigrationIterator($diff_table))->setPageSize($size);
$chunk_iter = new PhutilChunkedIterator($row_iter, $size);
foreach ($chunk_iter as $chunk) {
    $sql = array();
    foreach ($chunk as $diff) {
        $id = $diff->getID();
        echo pht('Migrating diff ID %d...', $id) . "\n";
        $phid = $diff->getPHID();
        if (strlen($phid)) {
            continue;
        }
        $type_diff = DifferentialDiffPHIDType::TYPECONST;
        $new_phid = PhabricatorPHID::generateNewPHID($type_diff);
        $sql[] = qsprintf($conn_w, '(%d, %s)', $id, $new_phid);
    }
    if (!$sql) {
        continue;
    }
    foreach (PhabricatorLiskDAO::chunkSQL($sql, ', ') as $sql_chunk) {
        queryfx($conn_w, 'INSERT IGNORE INTO %T (id, phid) VALUES %Q
        ON DUPLICATE KEY UPDATE phid = VALUES(phid)', $diff_table->getTableName(), $sql_chunk);
    }
}
echo pht('Done.') . "\n";
 private function loadDiffIDs($conn_r, array $revisions)
 {
     assert_instances_of($revisions, 'DifferentialRevision');
     $diff_table = new DifferentialDiff();
     $diff_ids = queryfx_all($conn_r, 'SELECT revisionID, id FROM %T WHERE revisionID IN (%Ld)
     ORDER BY id DESC', $diff_table->getTableName(), mpull($revisions, 'getID'));
     $diff_ids = igroup($diff_ids, 'revisionID');
     foreach ($revisions as $revision) {
         $ids = idx($diff_ids, $revision->getID(), array());
         $ids = ipull($ids, 'id');
         $revision->attachDiffIDs($ids);
     }
 }