Give the ability to turn off Missing instrumentation spans since there is nothing to instrument in many cases

[aellett]

Environment

SaaS (https://sentry.io/)

Steps to Reproduce

I've got a scoped transaction that I started manually. While that transaction is running, I start a span every time 1) there is a network request and 2) the user navigates to a different feature within the app.

As a visualization of this, you could imagine that I've got one long session. At any point within that session, some given feature should be running, which means that a span should be running underneath that session.

Also at any point during that session, a network request might be made, which would result in a span for that request. These request spans would be unevenly spaced out throughout a session.

Expected Result

Because the user navigates from one feature to another, I would expect my "feature" spans to end up exactly next to each other and not really leave any gaps for missing instrumentation.

The only time a feature span ends is when either 1) the session ends or 2) the user navigates to a different feature (which starts a new span).

Actual Result

When I look at a trace of a session where a user has moved between a couple features, I see large blocks of spans labeled "Missing instrumentation." It feels like instrumentation is not missing, since I've got both a transaction (for the session) and a span (for the feature) running at that point.

In the attached screenshot, the session transaction starts, then a feature span starts, and while both of those are active, I see two blocks for "Missing instrumentation."

It's not such a huge problem in this situation, but I've seen situations where the user stays in one feature and makes many network requests, and in that case I get an explosion of quite a lot of "Missing instrumentation" blocks, which makes it harder to view the waterfall and track what I'm looking at.

Product Area

Performance

Link

No response

DSN

No response

Version

No response

[getsantry[bot]]

Assigning to @getsentry/support for routing ⏲️

[getsantry[bot]]

Routing to @getsentry/product-owners-performance for triage ⏲️

[Dhrumil-Sentry]

@aellett - Currently we show missing instrumentation spans if there are gaps of over 100ms between span waterfall. There is no way for a user to turn this default behavior off.

But we'll take this feedback under active consideration 🙏