从多个 dynamodb 表中获取项目的好方法（低延迟）？

Question

I have several dynamodb tables, table A, table B, table C and table D.

I want to get item A from table A, item B from table B, item C from table C and item D from table D.

Currently I make 4 dynamodb getItem calls to 4 tables to get the items sequentially. Each call cost ~12 millisecond, total ~50 millisecond.

ItemA a = tableA.getItem("A");
ItemB b = tableB.getItem("B");
ItemC c = tableC.getItem("C");
ItemD d = tableD.getItem("D");

Is there a better way to make the calls to reduce latency? Not sure how i can make it parallel here.

Answer 1

If the requests, as in your example, are not dependent on one another - in other words, you don't need to know the result of the first request to send the second, you don't need to do them sequentially (one after another) - you can start all four in parallel.

How to start four requests in parallel depends on the specific programming you are using, but you have an even easier option: Send just one BatchGetItem request - with the four requests in it. DynamoDB will do all these requests in parallel for you.