Which of the following are types of Key Value Database?(Select Two)
- MongoDB
- PostgreSQL
- Redis
- etcd
Answer(s): C,D
Explanation:
etcd is an open source distributed key-value store used to hold and manage the critical information that distributed systems need to keep running. etcd's performance is heavily dependent upon storage disk speed, so it's highly recommended to use SSDs in etcd environments. Redis (for REmote DIctionary Server) is an open-source, in-memory, NoSQL key-value store that is used primarily as an application cache or quick-response database. Redis supports multiple data structures, built-in Lua scripting, multiple levels of on-disk persistence, and high availability. Redis is an in-memory data store and can function as a database, cache, or message broker.
Incorrect Answers:
MongoDB is an open source, non-relational database management system that uses flexible documents to process and store various forms of data. A NoSQL solution, MongoDB provides an elastic data model that enables users to store and query multivariate data types with ease. This not only simplifies database management for developers but also creates a highly scalable environment for applications and services. MongoDB uses documents or collections of documents as its basic unit of data. Formatted as JSON objects, these documents can store various types of data and be distributed across multiple systems. MongoDB offers a few capabilities that make it stand out from other database management systems, including load balancing, ad hoc database queries, and multi-language support. PostgreSQL, commonly pronounced "Post-GRES," is an open-source database that has a strong reputation for its reliability, flexibility, and support of open technical standards. PostgreSQL provides the ability to restore databases to a specific moment in time because it maintains a write-ahead log that logs every database change. PostgreSQL features built-in support for multiple procedural languages.