AWS SDK for .NET Documentation
IndexName Property
AmazonAmazon.DynamoDBv2.ModelGlobalSecondaryIndexIndexName Did this page help you?   Yes   No    Tell us about it...
The name of the global secondary index. The name must be unique among all other indexes on this table.

Constraints:

Length
3 - 255
Pattern
[a-zA-Z0-9_.-]+

Declaration Syntax
C#
public string IndexName { get; set; }

Assembly: AWSSDK (Module: AWSSDK) Version: 1.5.60.0 (1.5.60.0)