DATA3404 Lecture Notes - Lecture 12: Nosql, Petabyte, Scalability
22 Jun 2020
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Document Summary
Drivers for db: scalability, both in terms of data size and number of nodes, e. g. Yahoo announced first peta-byte database back in 2009. Cloud" data centres with several ten-thousand computers: de-coupled applications, the classic client-server does not cut it anymore on internet scale, schema flexibility. In some domains, we do not know schema in advance: and for hosted services, do not want to restrict on few fixed schemas, advanced data models, how to analyze large customer-product-like/friend network graphs in the scale of. Facebook, amazon, ebay : both a problem in scale and in query expressiveness. Get() and put() execution: route each request through a generic load balancer that will select a node based on load information, use a partition-aware client library that routes requests directly to the appropriate coordinator nodes. Vector clock: a vector clock is a list of (node, counter) pairs, every version of every object is associated with one vector clock.
