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Distributed Coordinator ED (Etcd): Distributed systems use etcd as a consistent key-value store for configuration management, service discovery, and coordinating distributed work. Many organizations use etcd to implement production systems such as container schedulers, service discovery services, and distributed data storage.
- Document Database PG (PostgreSql)
- Key Value Database AG (Apache Geode): Apache Geode provides a database-like consistency model, reliable transaction processing and a shared-nothing architecture to maintain very low latency performance with high concurrency processing.(https://geode.apache.org/docs/guide/114/getting_started/intro_to_clients.html) or (https://docs.spring.io/spring-boot-data-geode-build/1.7.5/reference/html5/).
- Key Value Database RD (Redis): RDB is NOT good if you need to minimize the chance of data loss in case Redis stops working.
- Wide Column Database CD (Apache Cassandra)
- Search Engine (Open Search): It supports Rest Api, https://opensearch.org/docs/latest/clients/java/
What open source client we can use already implemented? (custom, open-search client, ...)
Open Search
Create a composition index
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