Read-heavy datastore without a cache

warningread-heavy-path-without-cache

The design states a read-heavy workload and application servers read this datastore directly, yet the design has no cache anywhere. Every read pays a database round trip.

Severity: warning
Selects: every node of kind sql-database or nosql-database
Components in scope: 123

What it checks

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

— all of these hold:
— the design requirement `traffic.readWriteRatio` is a number greater than 10
— the node has at least one synchronous incoming edge from an app-server
— this does not hold:
— the design contains a node of kind cache

Message

Datastore '{{node.id}}' serves a read-heavy workload directly from application servers and the design has no cache.

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

Applies to · 123 components

NoSQL database nosql-database SQL database sql-database

Tripped by · 1

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.

object-storagereference

Source

1# yaml-language-server: $schema=../schema/rule.schema.json
2# The design states a read-heavy workload and application servers read this datastore
3# directly, yet no cache exists anywhere in the design. Every read pays a database round trip.
4# Tripped by: designs/object-storage.broken.yaml
5schemaVersion: "1"
6type: "rule"
7id: "read-heavy-path-without-cache"
8severity: "warning"
9select:
10  node:
11    kind: ["sql-database", "nosql-database"]
12when:
13  all:
14    - requirement: "traffic.readWriteRatio"
15      gt: 10
16    - hasEdge:
17        direction: "in"
18        mode: "sync"
19        peerKind: "app-server"
20    - not:
21        hasNode:
22          kind: "cache"
23message: "Datastore '{{node.id}}' serves a read-heavy workload directly from application servers and the design has no cache."

The same page as markdown, for an agent: /catalogue/rules/read-heavy-path-without-cache.md