Poor Performance REGEX Search is Slower than bif:contains bif:contains returns faster, because it uses special full-text indexing to get IDs of objects that contain words mentioned in the query. It does not scan the whole table like a Regex-based query. The advantage of REGEX is flexibility. One may search for specific fragments of words or for special data like protein coding sequences. Moreover, bif:contains may be used only for variables that are directly bound in object position of triple, not for values of expressions of any other sorts.