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chore(cohorts): Pause cohort dependency metrics on cache warm #39123

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Merged
merged 1 commit into from
Oct 6, 2025
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chore(cohorts): Pause cohort dependency metrics on cache warm #39123

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9 changes: 5 additions & 4 deletions posthog/models/cohort/dependencies.py
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@ def extract_cohort_dependencies(cohort: Cohort) -> set[int]:
return dependencies


def get_cohort_dependencies(cohort: Cohort) -> list[int]:
def get_cohort_dependencies(cohort: Cohort, _warming: bool = False) -> list[int]:
"""
Get the list of cohort IDs that the given cohort depends on.
"""
Expand All @@ -50,10 +50,11 @@ def get_cohort_dependencies(cohort: Cohort) -> list[int]:
cache_hit = cache.has_key(cache_key)

def compute_dependencies():
COHORT_DEPENDENCY_CACHE_COUNTER.labels(cache_type="dependencies", result="miss").inc()
if not _warming:
COHORT_DEPENDENCY_CACHE_COUNTER.labels(cache_type="dependencies", result="miss").inc()
return list(extract_cohort_dependencies(cohort))

if cache_hit:
if cache_hit and not _warming:
COHORT_DEPENDENCY_CACHE_COUNTER.labels(cache_type="dependencies", result="hit").inc()

result = cache.get_or_set(
Expand Down Expand Up @@ -114,7 +115,7 @@ def warm_team_cohort_dependency_cache(team_id: int, batch_size: int = 1000):
for cohort in Cohort.objects.filter(team_id=team_id, deleted=False).iterator(chunk_size=batch_size):
# Any invalidated dependencies cache is rebuilt here
dependents_map.setdefault(_cohort_dependents_key(cohort.id), [])
dependencies = get_cohort_dependencies(cohort)
dependencies = get_cohort_dependencies(cohort, _warming=True)
# Dependency keys aren't fully invalidated; make sure they don't expire.
cache.touch(_cohort_dependencies_key(cohort.id), timeout=DEPENDENCY_CACHE_TIMEOUT)
# Build reverse map
Expand Down
20 changes: 20 additions & 0 deletions posthog/models/cohort/test/test_dependencies.py
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Expand Up @@ -390,3 +390,23 @@ def test_cache_hit_miss_sequence(self):
cache_type="dependents", result="hit"
)._value._value
self.assertEqual(dept_hits_after_second, dept_initial_hits + 1)

def test_warming_does_not_increment_counters(self):
"""Verify that cache warming operations don't increment the counter metrics"""
cohort_a = self._create_cohort(name="Test Cohort A")
self._create_cohort(
name="Test Cohort B", groups=[{"properties": [{"key": "id", "type": "cohort", "value": cohort_a.id}]}]
)

cache.clear()

initial_hits = COHORT_DEPENDENCY_CACHE_COUNTER.labels(cache_type="dependencies", result="hit")._value._value
initial_misses = COHORT_DEPENDENCY_CACHE_COUNTER.labels(cache_type="dependencies", result="miss")._value._value

warm_team_cohort_dependency_cache(self.team.id)

# Verify counters did not increment during warming
final_hits = COHORT_DEPENDENCY_CACHE_COUNTER.labels(cache_type="dependencies", result="hit")._value._value
final_misses = COHORT_DEPENDENCY_CACHE_COUNTER.labels(cache_type="dependencies", result="miss")._value._value
self.assertEqual(final_hits, initial_hits)
self.assertEqual(final_misses, initial_misses)
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