Read Consistency

Eventually Consistent Reads

  • When you read data from a DynamoDB table, the response may not reflect the result of a recently completed write operation.
  • Responses may include some stale data.
  • If you repeat your read request after a short time, the response will return the latest data.

Strongly Consistent Reads

When you request Strongly Consistent Reads, DynamoDB returns a response with the most up-to-date data, reflecting updates from all previous writes that were successful. However, this consistency comes with some downsides:

  • Strongly Consistent Reads may not be available if there are network problems or outages. In this scenario, DynamoDB may return server error (HTTP 500).
  • Strongly Consistent Reads may have higher latency than eventually consistent reads.
  • Global secondary indexes are not supported Strongly Consistent Reads.
  • Strongly Consistent Reads uses double throughput capacity than eventually consistent reads.