Negative funnel time conversion bin times

[alexkim205]

Bug description

The new funnels time conversion endpoint sometimes returns bins with negative time values. This makes it difficult to reflect accurate time conversion funnels data on the frontend. @Twixes @neilkakkar

Example CH localhost link to reproduce bug.

Request Payload

Expected behavior

No negative time bin values.

How to reproduce

1. Navigate to new funnels time conversion page. Make sure to turn on this FF: 4535-funnel-bar-viz
2. Add a few identical actions/events
3. Open up network requests to see the response to api/funnels

Environment

• PostHog Cloud
• self-hosted PostHog, version/commit: please provide

Thank you for your bug report – we love squashing them!

[liyiy]

This is a graph that had those negative time values

[neilkakkar]

Very interesting: Not an issue with time to convert, but the underlying time averages. And it turns out, this happens sporadically: sometimes, the time conversion values are borked, (and in your unfortunate case, cached), so the graph appears like this^.

I tried clearing the cache, and making the request again, and it worked fine.

Sigh, now to figure out why event duplicates are flakey O.o

[neilkakkar]

Partially because of: ClickHouse/ClickHouse#26580 . And from what my experiments tell me, only happens when dealing with duplicate events. If the steps are not both $pageview, never happens. If the steps are both $pageview, happens sometimes.