DynamoDB Flashcards
What is AWS DynamoDB?
DynamoDB is a fast and flexible NoSQL DB service for all applications that need consistent, single-digit milliscond latency at any scale
Does DynamoDB support document data models?
Yes
Does DynamoDB support key-value data models?
Yes
Where is DynamoDB data stored?
On SSD storage
How does Dynamo DB provide data redundancy?
Data in DynamoDB is spread across 3 geographically distinct data centers
What is the data consistency model for DynamoDB?
Eventually Consistent Reads by Default
Strongly Consistent Reads as an option
Roughly when are Eventually Consistent Reads consistent?
Data consistency is usually reached within 1 second
What are Strongly Consistent Reads?
A strongly consistent read reflects all writes that received a successful response prior to the read.
What does DAX stand for?
DynamoDB Accelerator
What is AWS DAX?
Fully managed, highly-available in-memory cache for DynamoDB
What is the performance improvement offered by AWS DAX?
10x performance improvement over DB standalone
Reduces request time from milliseconds to microseconds
What does the developer need to do to manage the logic in AWS DAX?
Nothing. The caching logic is fully managed by AWS
Can AWS DAX also provide write speedup?
Yes, it is a write-through cache
What does DynamoDB Transactions assist with?
Atomic operations
(Think money transfer, can’t debit one account without crediting another)
How does using DynamoDB Transactions affect read/write capacity?
Transactions does 2 underlying reads or writes of every item in the transaction, one to prepare, and one to commit.