How deeply does 100 Go Mistakes and How to Avoid Them cover monotonic clock?

Defines both clock types, traces monotonic data loss through JSON, and contrasts ==, Equal, and Truncate(0).

Monotonic clock

As explained in 100 Go Mistakes and How to Avoid Them

A monotonic clock is a time source that advances steadily for measuring elapsed durations without being adjusted backward by wall-clock changes.

A monotonic clock advances steadily for measuring elapsed durations. Unlike a wall clock, it is not moved backward or forward by time jumps such as NTP corrections, although its frequency may be adjusted. section 10.3.2

Go's time.Time can hold both wall time and monotonic time. time.Now() supplies both, but JSON unmarshaling restores only wall time, so comparing the original and decoded values with == can unexpectedly return false. section 10.3.2

A misleadingly unequal timestamp

The original value prints a monotonic suffix such as m=+0.000338660, while the unmarshaled value does not. Their wall times match, but their monotonic components differ; == therefore prints false.

How 100 Go Mistakes and How to Avoid Them covers it

Cover of 100 Go Mistakes and How to Avoid Them

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Related concepts

clockcontrasts with · A computer clock is a timekeeping source or interface that provides time values or measurements to software.
steady clockincludes · A steady clock is a clock whose measured time never decreases and advances at a steady rate.
operating systemuses · An operating system is system software that manages computer hardware and provides services and interfaces for application programs.
meancontrasts with · A mean is a measure of central tendency, calculated as the arithmetic average of values or, for a random variable, as the probability-weighted average of its possible values.

This explainer was generated by Manning's knowledge graph from the text of 100 Go Mistakes and How to Avoid Them. The section links point to the parts of the book it draws on.