Amazon Simple Storage Service (S3) stores data for millions of applications used by market leaders in every industry.

With S3, I can store as many objects as I want and individual objects can be as large as 5 terabytes. Data in object storage have traditionally been accessed as a whole entities, meaning when you ask for a 5 gigabyte object you get all 5 gigabytes. It’s the nature of object storage.

By using S3 Select to retrieve only the data needed by your application, you can achieve drastic performance increases – in many cases you can get as much as a 400% improvement.

S3 Select is extremely useful when:
You have a large amount of structured data that can be queried upon.
Only a small portion of the object is relevant to your current needs.
You want to have partial data retrieval ability and get filtered data for user. You want to pre-filter S3 objects before performing additional analysis with tools like Spark or Presto. You want to reduce the volume of data that has to be loaded and processed by your applications thus, improving performance and thus, reducing cost.

The cost of S3 Select depends on two things — DATA SCANNED TO QUERY and DATA RETURNED. For example, if S3 query scans 5GB data and returns 2GB data, the cost for us-east-1 region would be :
Data Scanned by S3 SELECT : $0.002 / GB * 5 = $0.01
Data Returned by S3 SELECT : $0.0007/GB * 2 = $0.0014
Total = $0.0114 per S3 SELECT request.

To use S3 Select, your data must be structured in either CSV or JSON format with UTF-8 encoding. You can also compress your files with GZIP or BZIP2 before sending to S3 to save on object size.

select count(*) from s3object s
select * from s3object s limit 10
select * from s3object s where s.reqId='1000'
select * from s3object s where s.reqMethod='GET'
select * from s3object s where s.resStatusCode='401'
select * from s3object s where s.resStatusCode='200'
select * from s3object s where s.accept='application/json'