core-bundle/src/Resources/contao/dca/tl_page.php
public function purgeSearchIndex(Contao\DataContainer $dc)
	{
		if (!$dc->id)
		{
			return;
		}

		$objResult = $this->Database->prepare("SELECT id FROM tl_search WHERE pid=?")
									->execute($dc->id);

		while ($objResult->next())
		{
			$this->Database->prepare("DELETE FROM tl_search WHERE id=?")
						   ->execute($objResult->id);

			$this->Database->prepare("DELETE FROM tl_search_index WHERE pid=?")
						   ->execute($objResult->id);
		}
	}
public function purgeSearchIndex(Contao\DataContainer $dc)
	{
		if (!$dc->id)
		{
			return;
		}

		$objResult = $this->Database->prepare("SELECT id FROM tl_search WHERE pid=?")
									->execute($dc->id);

		while ($objResult->next())
		{
			$this->Database->prepare("DELETE FROM tl_search WHERE id=?")
						   ->execute($objResult->id);

			$this->Database->prepare("DELETE FROM tl_search_index WHERE pid=?")
						   ->execute($objResult->id);
		}
	}
Purge the search index if a page is being deleted

@param Contao\DataContainer $dc