perf: reuse event loop in BatchSpanProcessor instead of creating one per export#45
Merged
perf: reuse event loop in BatchSpanProcessor instead of creating one per export#45
Conversation
![cubic-dev-ai[bot]](https://avatars.githubusercontent.com/in/1082092?s=60&v=4){kind=small}
There was a problem hiding this comment.
1 issue found across 1 file
Prompt for AI agents (all issues)
Check if these issues are valid — if so, understand the root cause of each and fix them.
<file name="drift/core/batch_processor.py">
<violation number="1" location="drift/core/batch_processor.py:203">
P2: Reusing the export thread’s event loop without verifying the current thread can break force_flush when stop() times out. In that case, _force_flush() runs on a different thread and will attempt to drive the export thread’s loop, causing a RuntimeError. Gate the reuse on running in the export thread (or always create a temporary loop off-thread).</violation>
</file>
Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.
sohil-kshirsagar
approved these changes
Jan 18, 2026
This file contains hidden or 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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
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Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be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.
Summary
BatchSpanProcessorpreviously calledasyncio.new_event_loop()for every batch export when using async adapters. Creating and destroying event loops is expensive (involves allocating selectors, registering file descriptors, and other OS-level setup/teardown) and can show up as latency/jitter under load. This change creates a single long-lived event loop when the export thread starts and reuses it for all async exports.Changes
_thread_loopinstance variable to store the long-lived event loop_export_loop()instead of per-export_export_batch()for async adapter exportsfinallyblock when the export thread exits_force_flush()after shutdown (rare, one-time occurrence when the thread has already exited)tests/unit/test_batch_processor.py