Core

by using mounted pages i got problems the the search extension. after a few days in the search result page some hits of other domains in the same typo3-pagetree appears. i found this code in class.indexer.php:

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function updateRootline() {

$updateFields = array();
    $this->getRootLineFields($updateFields);

$GLOBALS['TYPO3_DB']->exec_UPDATEquery('index_section', 'page_id='.intval($this->conf['id']), $updateFields);
}
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called from line 595 in case, no update is nessesary. because the where class page_id this code overrides all records with other rootline infos (rl0-rl2) too.

what is the reason to update the rootline fields?