Single-writer primary at peak QPS

errorsingle-writer-primary-at-peak-qps

A single-writer, unsharded relational primary has a throughput ceiling. Declaring more than five thousand requests per second against it means the peak finds that ceiling in production.

Severity: error
Selects: every node of kind sql-database
Components in scope: 76

What it checks

It looks at every node of kind sql-database, and fires when:

— all of these hold:
— the node's `multiWriter` is false
— the node's `sharded` is false
— the node's declared requests per second is more than 5000

Message

Database '{{node.id}}' is a single unsharded writer declared at more than 5000 rps. Shard it or move to a multi-writer distributed store.

{{node.id}} style paths are filled in from the node, the edge or the design the finding is about.

Applies to · 76 components

SQL database sql-database

Tripped by · 15

Reference designs whose broken twin names this rule in its header. The gate reads the same header, and fails when a rule no design trips.

amazon-orderreference doordash-deliveryreference dropbox-syncreference etsy-searchreference facebook-taoreference github-mysqlreference gojek-platformreference hotstar-streamingreference reddit-feedreference shopify-flash-salereference stack-overflowreference uber-dispatchreference unique-id-generatorreference youtube-upload-playbackreference zerodha-kitereference

Source

1# yaml-language-server: $schema=../schema/rule.schema.json
2# A single-writer, unsharded relational primary has a ceiling. Declaring more than
3# 5000 requests per second against it means the peak will find that ceiling in
4# production, as the 1.6M QPS Aurora crash at DoorDash did.
5# Tripped by: designs/doordash-delivery.broken.yaml
6schemaVersion: "1"
7type: "rule"
8id: "single-writer-primary-at-peak-qps"
9severity: "error"
10select:
11  node:
12    kind: "sql-database"
13when:
14  all:
15    - prop: "multiWriter"
16      equals: false
17    - prop: "sharded"
18      equals: false
19    - nfr:
20        rps:
21          gt: 5000
22message: "Database '{{node.id}}' is a single unsharded writer declared at more than 5000 rps. Shard it or move to a multi-writer distributed store."

The same page as markdown, for an agent: /catalogue/rules/single-writer-primary-at-peak-qps.md