How to lose money with DynamoDb 💸
Jon Packer • RevolverConf 2024.1
(CONTEXT)
Hobby Project
Beer festival list app
Unique checkins
Avoid these beers at all costs
x-ratelimit-limit: 100 x-ratelimit-remaining: 0
✨ Untickd ✅
- AWS Lambda + API Gateway
- AWS Scheduled events
- Data stored in DynamoDb
GET /ticks/:userId
-> [{ "checkinId": 62137
"beerId": 23298,
"timestamp": "2022-11-23T18:43:22Z",
"rating": 4.25 }, ...and 8959 more]
GET /tick/:userId/:beerId
-> ❌: 404
-> ✅: { "checkinId": 62137
"beerId": 23298,
... etc }The Plan
- Store checkin histories in my database
- Scheduled update from Untappd once an hour
- Scale: 2000-3000 users, ~500-10000 checkins each
[foreshadowing]
Title Text
{
"id": 1,
"name": "A thing stored in DynamoDb",
"attributes": {
"contrived": true,
"array": [1, 2, 3]
}
}Store documents in this database!
** not a document database
**
Schema:
Users table
{
"userId": 12345, // primary key
"checkins": {
"<beer id>": {
"checkinId": 12345,
"timestamp": "2022-12-12T19:23:46Z",
"rating": 3.75
},
... and 8959 more
}
}Hmm, that's odd
Rewrite!
Checkins table
{
"checkinId": 12345, // primary key
"userId": 23456,
"beerId": 34567,
"timestamp": "2022-12-12T19:23:46Z",
"rating": 3.75
}To the moon 📈
Dramatic Reconstruction
❌ ProvisionedThroughputExceededException
📜 Secondary Indexes
