Queries with "Is not null" and "is valued" in predicate is not using secondary indexes.

1. create index idx_result on ds(result:string)
2. Run:

• Explain select result from ds where result is valued;
• Explain select result from ds where result is not null;

Observe that both the queries are not using secondary indexes.

For N1QL, "Is not null" or "is valued" uses secondary indexes.