> For the complete documentation index, see [llms.txt](https://karansingh.gitbook.io/aws-saa-c02/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://karansingh.gitbook.io/aws-saa-c02/advanced-s3-and-athena/select-and-glacier-select.md).

# Select and Glacier Select

![](https://4079160698-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-MOmHH1M7R1RV5MGm4F7%2F-MP-_bqKfeZdmxxYr0li%2F-MP-bn1PVy8aQqNB6qMK%2Fimage.png?alt=media\&token=32bccea5-0bea-4045-a4cf-e5941b1df74c)

* Retrieve only a subset of data from an object by using simple SQL expressions.<br>
* Can achieve drastic performance increases – As much as a 400% improvement.