Couchbase Server 4.5 introduces a range of new features and enhancements, particularly focusing on array indexing capabilities. The update includes performance improvements in N1QL queries through covering array indexes, which optimize queries by avoiding unnecessary data retrieval trips. To create covering array indexes, the array must be included as an index key in the CREATE INDEX statement, allowing N1QL to evaluate predicates effectively. The release also supports additional N1QL operators like UNNEST and ANY AND EVERY for array indexes, enhancing query flexibility. Using a covered array index significantly boosts query performance, as demonstrated by a query that executes 375 times faster when utilizing the new indexing features. The update further allows the use of keywords such as DISTINCT ARRAY and ALL to define array indexes and introduces rules for index selection to ensure queries leverage the most suitable index. Overall, Couchbase 4.5 aims to offer improved efficiency and functionality in managing complex data structures.