Reparenting spans to support inferred spans

[nehaduggal]

The java agent recently added support for inferring spans from statistical profiles. Because these inferred spans are collected in a different way when compared to the instrumented spans, these spans can not be parents of traced spans. Due to this reality, the current transaction waterfall is insufficient to properly visualize traces including inferred spans as detailed in the java agent documentation.

The proposal linked outlines the changes we will need to make in order to reparent these spans so they can properly visualized in the distributed tracking waterfall.

Link to proposal documentation

Link to Java agent issue

Link to APM server issue

Link to UI POC