{"id":"dynamodb-gsi-nonunique-partition-key-sort-key-disambiguates","text":"When a DynamoDB GSI partition key is non-unique (e.g., same URL bookmarked by multiple customers), the sort key is used to disambiguate — as demonstrated by the Bookmarks model's ByUrl index using customerId as sort key.","truth_value":"IN","source":"entries/2026/03/11/amazondynamodb-latest-developerguide-workbenchSampleModelshtml.md","source_url":"","source_hash":"2584c372aeb1871e","justifications":[],"dependents":[],"metadata":{},"explanation":{"steps":[{"node":"dynamodb-gsi-nonunique-partition-key-sort-key-disambiguates","truth_value":"IN","reason":"premise"}]}}