CRAQ
An enhancement of Chain Replication that introduces apportioned query handling on top of the original protocol. It is typically paired with coordination components such as ZooKeeper to implement the control plane and supports dynamic chain reconfiguration to improve high availability.
Timeline (last 90 days)
CRAQ (Chain Replication with Apportioned Queries), proposed by Terrace and Freedman in 2009, allows all nodes on the chain to respond to read requests in order to horizontally scale read throughput.
CRAQ maintains two states for each object—a committed version and a dirty version; a non-tail node can respond to read requests locally when it holds a committed state, otherwise it must query the tail node for the latest committed version number.
All Facts (2)
CRAQ (Chain Replication with Apportioned Queries), proposed by Terrace and Freedman in 2009, allows all nodes on the chain to respond to read requests in order to horizontally scale read throughput.
50%UnverifiedCRAQ maintains two states for each object—a committed version and a dirty version; a non-tail node can respond to read requests locally when it holds a committed state, otherwise it must query the tail node for the latest committed version number.
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