Crate sdcons

Source
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§sdcons

sdcons is an implementation of geo-replicated distributed consensus algorithm. It is based on the paper:

SDPaxos: Building Efficient Semi-Decentralized Geo-replicated State Machines (ACM Symposium on Cloud Computing 2018, SoCC ’18)

Like original SDPaxos, sdcons provides one-round-trip latency reading and writing capabilities under realistic configurations (deployed with three or five nodes).

In addition, I ported some optimizations mentioned in the raft algorithm to SDPaxos. Including:

  • log term
  • leader election
  • leadership transfering
  • membership configuration (joint consensus)
  • batched & pipelined log replication
  • lease reading

These optimizations make SDPaxos easier to implement and verify.

However, the current sdcons has not yet implemented the Straggler detection mentioned in the SDPaxos paper.

Unlike SDPaxos, sdcons uses the term channel to represent the paxos commiting progress. The Ordering instance is represented as Index, the Command instance is represented as Entry. Because the term index is used to represent Ordering instance, I choose term id to represent the index in raft.

Re-exports§

pub use crate::storage::LogMetaView;

Modules§

constant
The crate constant defines a set constant used by sdcons.
storage
The crate storage defines a set of structs and traits which are used to store/access log sequences.
types
The crate types defines a set types used by sdcons.

Structs§

MsgBuilder
A helper struct contains all infos about how to create a message.
PostReady
A struct records info generated by RawNode::advance() and used in RawNode::post_advance().
RawNode
A structure that users can use directly, and any sdcons-related operations need to be forwarded through this structure.
SdconsOption
The options for create a sdcons node.
WriteTask
WriteTask records all info to persistent.

Enums§

Control
A set of operations is used to control the inner state of sdcons.
Error

Traits§

AdvanceTemplate
A template-method trait descript the actions used in RawNode::advance().
LogReader
A trait is used by RawNode to load logs from persistent device.
RoleObserver
A trait describes a set observer function invoked when a channel role is changed.