Distributed Algorithm - Standard Problems

Standard Problems

Atomic commit

An atomic commit is an operation where a set of distinct changes is applied as a single operation. If the atomic commit succeeds, it means that all the changes have been applied. If there is a failure before the atomic commit can be completed, the "commit" is aborted and no changes will be applied.

Algorithms for solving the atomic commit protocol include the two-phase commit protocol and the three-phase commit protocol.

Consensus

Consensus algorithms try to solve the problem of a number of processes agreeing on a common decision.

More precisely, a Consensus protocol must satisfy the four formal properties below.

• Termination: every correct process decides some value.
• Validity: if all processes propose the same value, then every correct process decides .
• Integrity: every correct process decides at most one value, and if it decides some value, then must have been proposed by some process.
• Agreement: if a correct process decides, then every correct process decides .

A typical algorithm for solving consensus is the paxos algorithm.

Distributed search

Leader election

Leader election is the process of designating a single process as the organizer of some task distributed among several computers (nodes). Before the task is begun, all network nodes are unaware which node will serve as the "leader," or coordinator, of the task. After a leader election algorithm has been run, however, each node throughout the network recognizes a particular, unique node as the task leader.

Mutual exclusion

Reliable Broadcast

Reliable broadcast is a communication primitive in distributed systems. A reliable broadcast is defined by the following properties:

• Validity - if a correct process sends a message, then some correct process will eventually deliver that message
• Agreement - if a correct process delivers a message, then all correct processes eventually deliver that message
• Integrity - every correct process delivers the same message at most once and only if that message has been sent by a process

A reliable broadcast can have sequential, causal or total ordering.

Replication

Resource allocation

Spanning tree generation

Symmetry breaking, e.g. vertex coloring