Sample transform "group_by" explanation

[tbenade]

Hi,

Can someone please help me understand what this sentence means.

If left unspecified, or if the event doesn't have group_by, then the event is not sampled separately

What does "or if the event doesn't have group_by". What does it mean for an event to have group_by.

vector/website/cue/reference/components/transforms/base/sample.cue

Line 13 in 4ad3fdc

If left unspecified, or if the event doesn't have `group_by`, then the event is not

[pront]

https://vector.dev/docs/reference/configuration/transforms/sample/#group_by

This field is templatable. If it's a constant though, then all events will be treated as a single group. Sampling will apply to that single group. If a template is specified, then groups will be created dynamically. Sampling applies to each group.