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Performance degradation in google-api-core #16552
Description
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Summary of the issue
Context
Upgrading google-api-core from version 2.27.0 to 2.28.1 (and later) has caused a significant spike in CPU usage. While version 2.27.0 maintains a steady 20–40% utilization, versions 2.28.1 and above consistently reach 100% CPU consumption.
Expected Behavior:
Same consumption of CPU as in 2.27.0
Actual Behavior:
CPU consumption increased up to 5 times.
API client name and version
google-api-core v. 2.28.1 - 2.30.0
Reproduction steps: code
file: main.py
import time
import importlib
import google.api_core
time.sleep(5)
def test_api_core():
importlib.reload(google.api_core)
for _ in range(2000):
test_api_core()
print("Successfully imported 2000 times.")Reproduction steps: supporting files
file: Dockerfile
FROM python:3
WORKDIR /app
RUN pip install --no-cache-dir google-api-core==2.28.1 grpcio
COPY main.py .
CMD ["python", "main.py"]
Reproduction steps: actual results
docker stats:
2.30.0
2.27.0
Reproduction steps: expected results
OS & version + platform
No response
Python environment
No response
Python dependencies
No response
Additional context
No response
Activity
daniel-sanche commentedon Apr 3, 2026
Do you see a performance degredation during usage, or just at import time?
This seems likely related to the new version support check. But that should be a one-time cost
Crowiant commentedon Apr 7, 2026
Hello @daniel-sanche I see performance degradation during usage. It is really a one-time cost for 2.27.0 . CPU usage spikes once and then drops to 0. But for version higher than 2.27.0 spike lasts during all imports. So each import causes CPU consumption up to 100%.
bonauer-pf commentedon Apr 8, 2026
This is likely the same regression that also leads to #15015, which is only reproducible in large venvs.
We are also affected by this, and every google cloud library takes 3-4s to import since the version bump, inflating our total startup times by >10s.
bonauer-pf commentedon Apr 8, 2026
Isolated the slow call to be
importlib.metadata.package_distributions(), which has to scann all package metadata in the venv and takes >1s. Code location:google-cloud-python/packages/google-api-core/google/api_core/_python_version_support.py
Line 159 in 281eaae
This gets called at import time for every Google Cloud module, sometimes multiple times.
vchudnov-g commentedon Apr 8, 2026
@bonauer-pf 's #16579 seems like a promising fix. Thanks!
vchudnov-g commentedon Apr 8, 2026
To clarify: I believe the issue arises here: recent versions of
api_corenow include these symbols, and so we were calling the function doing these checks every time we imported a new library. The memoization in #16579 should alleviate that.fix(perf): avoid repeated scan of entire venv via packages_distributi…
daniel-sanche commentedon Apr 10, 2026
This should be fixed in the latest version, but let me know if this is still an issue