StunDB - A stunning distributed key-value database

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Disclaimer

This application is work in progress, so it is not ready for production yet.

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Running

Jar

1. Download the runnable jar from the latest release
2. In the same folder where the jar is placed, create a file named application.yml with contents similar to this
3. Run the application with the following command:

  java -jar stundb-application-1.0.0-shaded.jar -Dapplication.port=8000

Maven

To run with Maven, you just need to run the following command:

  mvn exec:java -f stundb/application/pom.xml

Deploying to Maven Central

Run tests and then deploy to Maven Central:

  mvn clean test -P runAcceptanceTests 
  mvn clean deploy -P publishToCentral -pl \!io.github.rafaelsilverioit:stundb-acceptance-tests

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Backlog

Done

• FIFO cache
• Locking
• Contact other nodes through seeds
• Replicate data (using CRDT)
• Leader election
• Use Netty for TCP server
• Implement node statuses so that when a node becomes unreachable, it is ignored until it becomes available again and state is synchronized (remove leader status too)
• Retry contacting seeds until a node replies, up to a maximum number of attempts
• Move from Kryo to Apache Fury
• Use a BTree to store data
• Support JPMS
• TTL/Cache invalidation
• Create a Spring Boot app to observe nodes and expose actions through a REST API
• 100% unit testing coverage for the application module
• Acceptance tests for critical journeys
• Use Netty for TCP client
• Authentication (SCRAM/SASL)

Done & later removed

• Allow state persistence
• Use Java Sockets for TCP client

Doing

• Deal with virtual clocks - Already have implemented an initial version clock, but still need to get rid of timestamps
• Change how synchronization works today - Initial change: nodes replicate changes to the leader node, then from time to time, nodes synchronize with the leader to sync their state with the entire cluster
• TESTS (unit & acceptance)!

TODO

• TLS Encryption
• Support multiple cache eviction policies
• Create a node gateway app to receive requests from clients, and load balance requests between nodes
• Payload compression/decompression when talking between nodes