Predicate suggestion in console tab very slow with large schema

Moved from GitHub ratel/222

Posted by EnricoMi:

With a schema of 250k predicates typing queries in the console tab is very cumbersome. Typing the first letter of a predicate, Ratel filters for matching predicates and provides a long long list of predicates. This takes like 30 seconds for the first letter and makes the browser stall. A predicates list of thousands of entries is of questionable value. The list of suggestions should be limited to the top 20 or 50. This improves performance and UX.