Cover index in Couchbase

SQL++
1

How does couchbase decided to cover an index. I have created two indexes but when i look into execution plan one is covered and other is not.

created index idx_123 on bucket( value1,value2,value3,value4,value5,value6) where type=“ABC”

Create index idx_324 on bucket (a,b,c,d) where type=“PQR”

What metrics does it consider for taking this decision?

2

If index has all the information that required by query then it uses covered index.
If plan uses UnionScan, IntersectScan will not cover the query.

3

so my query is
Select a,b,c,d from bucket where type=PQR and
a=""
and b=""
group by c,d.

But i can see in plan it is not getting covered though index has all data

4

PQR must be string.

Select a,b,c,d from bucket where type="PQR" and
a=""
and b=""
group by c,d

If you have issue post the full EXPLAIN and index definition.

5

yes let me share execution plan