Configure exponential backoff while polling for tasks during the pipeline.
Positive numeric of length 1, minimum polling interval in seconds. Must be at least
Positive numeric of length 1, maximum polling interval in seconds. Must be at least
Positive numeric of length 1, greater than or equal to 1. Multiplicative rate parameter that allows the exponential backoff minimum polling interval to increase from
max. Actual polling intervals are sampled uniformly from the current minimum to
This function is for advanced usage only. Most users
should not need to modify the default exponential backoff.
To configure exponential backoff for a pipeline,
supply the output of
tar_backoff() to the
tar_option_set() in the
_targets.R file. See the Backoff
section of the help file for details.
In high-performance computing it can be expensive to repeatedly poll the
priority queue if no targets are ready to process. The number of seconds
between polls is
runif(1, min, max(max, min * rate ^ index)),
index is the number of consecutive polls so far that found
no targets ready to skip or run, and
are arguments to
(If no target is ready,
index goes up by 1. If a target is ready,
index resets to 0. For more information on exponential,
backoff, visit https://en.wikipedia.org/wiki/Exponential_backoff).
max is kinder to the CPU etc. but may incur delays
in some instances.