ref(opentelemetry): Avoid sampling work for non-root spans #15820
+62
−67
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
mydea
changed the title
AbhiPrasad
reviewed
Mar 25, 2025
| // We only sample based on parameters (like tracesSampleRate or tracesSampler) for root spans (which is done in sampleSpan). | ||
| // Non-root-spans simply inherit the sampling decision from their parent. | ||
| if (!isRootSpan) { | ||
| return wrapSamplingDecision({ |
There was a problem hiding this comment.
Don't we have to run this._client.emit('beforeSampling' for this as well?
There was a problem hiding this comment.
I don't think so, we only use this (today) in Next.js, where I assume this is for root spans:
// There are situations where the Next.js Node.js server forwards requests for the Edge Runtime server (e.g. in
// middleware) and this causes spans for Sentry ingest requests to be created. These are not exempt from our tracing
// because we didn't get the chance to do `suppressTracing`, since this happens outside of userland.
// We need to drop these spans.cc @lforst ?
There was a problem hiding this comment.
Looks fine to me! If you want to confirm you can look at the dumps from the E2E tests.
There was a problem hiding this comment.
I mean all the tests are passing, I would assume something would fail if this breaks it :) (and sampling should not be applied to child spans anyhow, so this should be fine!)
mydea
force-pushed
the
fn/streamline-sampling-spans
branch
from
a1f2f91 to
f47b0d8
Compare
AbhiPrasad
approved these changes
Mar 26, 2025
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Related to #15725 (comment)
When a span is not a root span, we do not need to do sampling work for it. By reordering stuff in the
shouldSamplefunction, we should be able to save a bunch of operations for the vast majority of (non-root) spans.I think this should be just fine!