summarise is used to summarise data on each node: reduce is then used to ensure that there's one overall summary
Usage
reduce(.self, ..., auto_compact = NULL)
reduce_(.self, ..., .dots, auto_compact = NULL)
Arguments
.self
Data frame
...
Additional parameters
auto_compact
Compact data after operation
.dots
Workaround for non-standard evaluation
Value
Data frame
Details
When data have not been grouped, calling summary(...) will result
in each node summarising the data it has available. This means that if
there are 3 nodes in the cluster, then there will be 3 summary values.
reduce is used to bring all those together to a single value.