When is the sampling-based profiler (profiling_inferred_spans_enabled) expected to be out of beta?
Configuration reference | APM PHP Agent Reference [1.x] | Elastic says:
This functionality is in technical preview and may be changed or removed in a future release. Elastic will work to fix any issues, but features in technical preview are not subject to the support SLA of official GA features.
A simple bottleneck (like sleep(10);) is shown in the trace sample only when using this type of profiling.