HLClock v0.1.6 HLClock View Source

Hybrid Logical Clock

Provides globally-unique, monotonic timestamps. Timestamps are bounded by the clock synchronization constraint, max_drift.

In order to account for physical time drift within the system, timestamps should regularly be exchanged between nodes. Generate a timestamp at one node via HLClock.send_timestamp/1; at the other node, call HLClock.recv_timestamp/2 with the received timestamp from the first node.

Inspired by https://www.cse.buffalo.edu/tech-reports/2014-04.pdf

Link to this section Summary

Functions

before?(t1, t2)

Determines if the clock's timestamp "happened before" a different timestamp

max_drift()

Configurable clock synchronization parameter, ε. Defaults to 300 seconds

now()

Functionally equivalent to using send_timestamp/0. This generates a timestamp for local causality tracking

recv_timestamp(remote)

Given the current timestamp for this node and a provided remote timestamp, perform the merge of both logical time and logical counters. Returns the new current timestamp for the local node

send_timestamp()

Generate a single HLC Timestamp for sending to other nodes or local causality tracking

Link to this section Functions

before?(t1, t2) View Source

Determines if the clock's timestamp "happened before" a different timestamp

max_drift() View Source

Configurable clock synchronization parameter, ε. Defaults to 300 seconds

now() View Source

Functionally equivalent to using send_timestamp/0. This generates a timestamp for local causality tracking.

recv_timestamp(remote) View Source

Given the current timestamp for this node and a provided remote timestamp, perform the merge of both logical time and logical counters. Returns the new current timestamp for the local node

send_timestamp() View Source

Generate a single HLC Timestamp for sending to other nodes or local causality tracking