perf: Use max_bytes_before_external_group_by for funnels and path que…

[timgl]

…ries

Problem

Some queries fail with OOM errors. They don't actually have to fail, it could just swap to disk instead.

Changes

👉 Stay up-to-date with PostHog coding conventions for a smoother review.

Does this work well for both Cloud and self-hosted?

How did you test this code?

[sentry-io]

🔍 Existing Issues For Review

Your pull request is modifying functions with the following pre-existing issues:

📄 File: posthog/hogql_queries/insights/funnels/funnels_query_runner.py

Function	Unhandled Issue
calculate	ValidationError: 1 validation error for HogQLQueryResponse posthog.tasks.tasks.process_... Event Count: 28
calculate	ValidationError: ["Filter parameter funnel_to_step can only be one of 1 for time to convert!"] ... Event Count: 17
calculate	Cohort.DoesNotExist: Cohort matching query does not exist. posthog.tasks.tasks.process_... Event Count: 4
calculate	IndexError: list index out of range posthog.tasks... Event Count: 2
calculate	ValidationError: ["Filter parameter funnel_to_step can only be one of 1, 2 for time to convert!"] ... Event Count: 1

📄 File: posthog/hogql_queries/insights/paths_query_runner.py (Click to Expand)

Function	Unhandled Issue
calculate	UnboundLocalError: local variable 'span' referenced before assignment posthog.tasks.tas... Event Count: 1

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[fuziontech]

checks out ✅
🚢 it

[thecatontheflat]

It seems like there is no way to enforce the "spill to disk" behavior anymore, because it just defaults to 0 in many cases now?