26 lines
1.2 KiB
Markdown
26 lines
1.2 KiB
Markdown
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# Key-value store
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## Abstraction: hash table
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A key-value store generally allows for O(1) reads and writes and is often backed by memory or SSD. Data stores can
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maintain keys in [lexicographic order](https://en.wikipedia.org/wiki/Lexicographical_order) , allowing efficient
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retrieval of key ranges. Key-value stores can allow for storing of metadata with a value.
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Key-value stores provide high performance and are often used for simple data models or for rapidly-changing data, such
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as an in-memory cache layer. Since they offer only a limited set of operations, complexity is shifted to the application
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layer if additional operations are needed.
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A key-value store is the basis for more complex system systems such as a document store, and in some cases, a graph
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database.
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## Source(s) and further reading: key-value store
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- [Key-value database](https://en.wikipedia.org/wiki/Key-value_database)
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- [Disadvantages of key-value stores](http://stackoverflow.com/questions/4056093/what-are-the-disadvantages-of-using-a-key-value-table-over-nullable-columns-or)
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- [Redis architecture](http://qnimate.com/overview-of-redis-architecture/)
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- [Memcached architecture](https://www.adayinthelifeof.nl/2011/02/06/memcache-internals/)
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