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# System prepended metadata

title: Cloud vendor for MVP

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# Cloud vendor for MVP
* AWS :white_check_mark: 
* GCP

AWS provides free tier quota for many services. I have not worked on GCP so not sure about it. Let's sketch basic architecture and compare service charges.

**I'm considering AWS as of now**

# Question Table Structure

**We should use dynamo db for our question storage**

| Exam Name[P] | Subject Name[P] | Topic[P] | Difficulty level[P]| creation time[S]| QuestionId[S] |Question Text[GS] | Question image path on S3| List of answers path on S3|
| -------- | -------- | -------- |--|--|--|--|--|--|
|      |      |      |

**P** stands for partition key
**S** stands for sorting key
**GS** stands for global secondary index [needed to figure out similar questions effectively]

# Query Pattern on Question table
* for given exam, subject, topic get difficult/easy question
* for given exam, subject, topic, difficulty level get questions which take time x minutes to solve
* for given questionId get question
* for given user get all his asked and answered questions
* Delete question


# Questions and Answers will be stored as image on S3

We'll use **AWS Cloudfront CDN** for fast image retrieval (inspired from Instagram arch)

# Feeds
**AWS ElastiCache**

# Authentication
**AWS cognito**