Improved Response Time Using the DOMAIN_INDEX_SORT Hint

You can also optimize for response time using the related DOMAIN_INDEX_SORT hint. Like FIRST_ROWS(n), when queries are optimized for response time, Oracle Text returns the first rows in the shortest time possible.

For example, you can use this hint as follows

select /*+ DOMAIN_INDEX_SORT */ pk, score(1), col from ctx_tab 
            where contains(txt_col, 'test', 1) > 0 order by score(1) desc;

However, this hint is only rule-based. This means that Oracle Text always chooses the index which satisfies the ORDER BY clause. This might result in sub-optimal performance for queries in which the CONTAINS clause is very selective. In these cases, Oracle recommends that you use the FIRST_ROWS(n) hint, which is fully cost-based.