protected function deleteUnusedColumnsFromKeywordsDataTable(DataTable $dataTable)
{
$columnsToDelete = array(Metrics::INDEX_NB_UNIQ_VISITORS, Metrics::INDEX_PAGE_IS_FOLLOWING_SITE_SEARCH_NB_HITS, Metrics::INDEX_PAGE_ENTRY_NB_UNIQ_VISITORS, Metrics::INDEX_PAGE_ENTRY_NB_ACTIONS, Metrics::INDEX_PAGE_ENTRY_SUM_VISIT_LENGTH, Metrics::INDEX_PAGE_ENTRY_NB_VISITS, Metrics::INDEX_PAGE_ENTRY_BOUNCE_COUNT, Metrics::INDEX_PAGE_EXIT_NB_UNIQ_VISITORS);
$dataTable->deleteColumns($columnsToDelete);
}