Cassandra at Yelp

Yelp — . 30 . , 5 . . Yelp Cassandra. , Cassandra Day Russia 2021 , Database Reliability Engineer Yelp.

Cassandra — NoSQL. , distributed wide-column NoSQL datastore. Cassandra write’, consistency .

, , Cassandra Yelp. . MySQL Cassandra. MySQL , Cassandra . , .

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2. Cassandra. — Cassandra- host port, . , - .
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Cassandra Yelp

90 , 60 Kubernetes- 500 ( — Cassandra).

, Read Load — 600 . RPS , Write Load — 400 RPS. .

Yelp . , . , - batch-, -, Cassandra - Cassandra.

- Cassandra. Cassandra , - ; Cassandra caching- distributed tracing — Yelp, , ( ).

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Cassandra : us-east us-west.

, us-east us-west, multi region cluster. us-east, , us-west.

( Kubernetes) Kubernetes-. — Cassandra: , , - CPU . , , , — . , .

, , , , . , , . etcd. Etcd — distributed key-value store.

AWS, EBS volumes — Amazon Elastic Block Storage. Kubernetes, .

, Smartstack, Envoy.

Yelp (Schema Changes)

: (schema), , — . Cassandra node , , , Cassandra, , - (, - ), Cassandra , — , .

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, , , Database Reliability, . , SQL-, , , : , , , , , - .

. , , . , , - , , . — . - SQL statement .

. Yelp pushplan — , , - . . , . , , pushplan. pushplan- Cassandra.

, Yelp. keyspace Cassandra, pushplan dev-, , utility- , pushplan. pushplan, , : Jira-, , , keyspace, . SQL-.

SQL-. , , create table. «» pushplan, … , , SQL-.

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• SQL-. , , . , , .
• DRE- best practices. , , primary key; - 20 pushplan — . .

.

Cassandra

, Cassandra : Cassandra- Cassandra-.

. , Cassandra, web application .

Cassandra- , , Cassandra- : host-, . , - , Cassandra, — . , .

, proxy-, Apollo. Python, Cassandra-.

. -, , Cassandra, host port, , Cassandra. . — host port Apollo.

SmartStack, , Apollo. host port, : « Apollo», SmartStack .

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— , , DRE, Cassandra-. , , Cassandra, , scale up scale down , , . .

proxy- .

Apollo-. , , - , , .

: — . Query-. . , , , .

, — -… , - 140 40 . 60 . -. , , 60 integration-, . .

, select-, .

, , GET_REVIEWS, , , SQL- .

unit-, swagger spec, — end point API Apollo, fake data — end-to-end .

, ( pushplan) , , . , . , - , , . Apollo , : , . .

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1. . .
2. Cassandra-, , .

, Stargate. Open Source , DataStax. API . .

Cassandra-, , , . , , — . , consistency requirements, , .

Stargate. Stargate Cassandra- . : … , Stargate . : , , , . proxy Stargate.

, Stargate… Cassandra, , API . REST API, gRPC, WebSocket GraphQL.

GraphQL API.

GraphQL

Stargate Cassandra schema — , key space , GraphQL-. : Type-safe API. GraphQL over under fetching. : . , Apollo. Cassandra- . , , - .

GraphQL API development . , Facebook ( ), Twitter, Github. Yelp GraphQL.

, . , , - Yelp. , MVP ( Stargate ) — , Yelp.

Stargate

Apollo, Stargate : ( node), Cassandra- , — 100 , 3 . RPS 24 . ? : Cassandra ? ?

, 24 3 . RPS.

rage of latencies , . (high tail) (99.9+), spite.

, Stargate :

1. , , CPU , . high tail latencies, JVM, Stargate .
2. , , Stargate.

Client libraries

, , ? : http-, REST-. .

swagger spec — endpoint, . API endpoint — GraphQL/{keyspace}. keyspace GraphQL-. : swagger spec Client Libraries.

, , Client Libraries , , , , , , .

, Stargate-. Client Library, GraphQL Query .

:

1. Service Discovery ( , host port).
2. request budget. , , - Yelp 2 . , 100 . , -.
3. distributed tracing — , .
4. : , , 200 .

GraphQL Playground

Playground — development environment, . GraphQL, Playground. Stargate out of the box. IDE, /graphqlschema, Cassandra-, GraphQL Queries.

: , , .

Operability

Operability, Stargate, , , Yelp-. — Distributed Tracing Integration. — , - Stargate. , Load… , , CPU, …

Stargate Cassandra-, property, Cassandra- . ( - ) TLS .