Couchbase Server indexes enhance the performance of query and search operations.
The following forms of index are available:
Primary: Provided by the Index Service, this is based on the unique key of every item in a specified bucket. Every primary index is maintained asynchronously. A primary index is intended to be used for simple queries, which have no filters or predicates. For information on creating a primary index, see CREATE PRIMARY INDEX.
Secondary: Provided by the Index Service, this is based on an attribute within a document. The value associated with the attribute can be of any type: scalar, object, or array.
A Secondary Index is frequently referred to as a Global Secondary Index, or GSI. This is the kind of index used most frequently in Couchbase Server, for queries performed with the N1Ql query-language. GSIs are also likely to be used extensively by the Analytics Service.
Full Text: Provided by the Search Service, this is a specially purposed index, which contains targets derived from the textual contents of documents within one or more specified buckets. Text-matches of different degrees of exactitude can be searched for. Both input and target text-values can be purged of irrelevant characters (such as punctuation marks or html tags). For information on how to create Full Text Indexes, see Creating Indexes.
View: Supports Couchbase Views, with fields and information extracted from documents.