Tuning and Query Performance
Group By and Aggregate Performance
N1QL Pushdowns optimize the performance of N1QL queries by supporting GROUP BY and Aggregate expressions.
A covering index includes the actual values of all the fields specified in the query, and does not need to fetch the values from the data service. Covered queries are faster and deliver better performance.
In Couchbase Server 6.6 Enterprise Edition and later, the Flex Index feature provides the ability for a N1QL query to use a Full Text Search index transparently with standard N1QL syntax.
The cost-based optimizer takes into account the cost of memory, CPU, network transport, and disk usage when choosing the optimal plan to execute a query.