question: void purgeOrphanedArticles ( ) { if ( ! isDBAvailable ( ) ) return ; long time = System . currentTimeMillis ( ) ; safelyDeleteArticles ( "feedId NOT IN (SELECT _id FROM " + TABLE_FEEDS + ")" , null ) ; Log . d ( TAG , "purgeOrphanedArticles took " + ( System . currentTimeMillis ( ) - time ) + "ms" ) ; }
target:  delete articles, which belongs to non-existent feeds