AOSPERF04-BP03 Use the flat object type for nested objects - Amazon OpenSearch Service Lens
Implementation guidanceResources

AOSPERF04-BP03 Use the flat object type for nested objects

Improve efficiency by using flat object types for indexing and querying complex data structures, reducing storage and retrieval overhead.

Level of risk exposed if this best practice is not established: Medium

Desired outcome: You use flat object types for indexing and querying complex data structures, which improves the efficiency of your storage and retrieval of nested objects.

Benefits of establishing this best practice:

  • Efficient reads: Fetching performance is similar to that of a keyword field.

  • Memory efficiency: Storing the entire complex JSON object in one field without indexing all of its subfields reduces the number of fields in an index.

  • Space efficiency: OpenSearch does not create an inverted index for subfields in flat objects, which saves space.

  • Compatibility for migration: You can migrate your data from systems that support similar flat types to OpenSearch.

Implementation guidance

The flat object field type treats the JSON object as a string, allowing subfield access without indexing for faster lookup and addressing performance concerns.

Flat objects are defined in the mapping of an index, either at creation time or by adding a new field that is flat object type. You cannot change an existing field to use flat object.

Implementation steps

  • Create a mapping for your index where issue is of type flat_object: 

PUT /test-index/
        {
        "mappings": {
        "properties": {
        "issue": {
        "type": "flat_object"
        }
        }
        }
        }

Resources