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DAX (Dynamo DB Accelerator)

A fully managed, clustered in-memory cache for DynamoDB * Delivers up to 10x read performance improvement * Microsecond performance for millions of requests per second * Ideal for Read-Heavy and bursty workloads e.g. auction applications, gaming and retail sites during black Friday promotions

How DAX Works

• Dax is a write-through caching service - data is written to the Cache as well as the back end store at the same time
• Allows you to point your DynamoDB API calls at the DAX cluster
• If the item you are querying is in the cache (cache hit), DAX returns the result to the application
• If the item is not available (cache miss) then DAX performs an Eventually Consistent GetItem operation against DynamoDB
• Retrieval of data from DAX reduces the read load on DynamoDB tables
• May be able to reduce Provisioned Read Capacity

What DAX is not suitable for

• Caters for Eventually Consistent reads only - no not suitable for applications that require Strongly Consistent Reads
• Write intensive applications
• Applications that do not perform many read operations
• Applications that do not require microsecond response times

Exam Tips - DAX

• Provides in-memory caching for DynamoDB tables
• Improves response times for Eventually Consistent reads only
• You point your API calls to the DAX cluster instead of your table
• If item you are querying is on the cache, DAX with return it; otherwise it will perform an Eventually Consistent GetItem operation to your DynamoDB table
• Not suitable for write-intensive applications or applications that require Strongly Consistent Reads