Funnel Unordered Steps #4868

neilkakkar · 2021-06-24T14:48:10Z

Changes

Fixes #4848

Checklist

All querysets/queries filter by Organization, by Team, and by User
Django backend tests
Jest frontend tests
Cypress end-to-end tests
Migrations are safe to run at scale (e.g. PostHog Cloud) – present proof if not obvious
Frontend/CSS is usable at 320px (iPhone SE) and decent at 360px (most phones)
Breaking changes are backwards-compatible. Ensure old/new frontend requests work with new/old backends, and vice versa.

…t for conversion window;

… cleanup via destroy() method

…ed funnel_persons and funnel_trends_persons into individual classes;

…com:PostHog/posthog into funnel-persons-pagination-conversion-window

…l-step-query-new

* dedup + tests * deep equality. Tests to come * write test for entity equality * finish testing funnels * clean up comments

EDsCODE

Have you tested the query generated here on production data too? Just to make sure it's relatively performant

ee/clickhouse/queries/funnels/funnel_unordered.py

neilkakkar · 2021-06-25T14:56:24Z

Good idea, haven't done that for a big funnel, will do!

…to funnel-unordered-step

neilkakkar · 2021-06-25T15:30:56Z

Will hold off on merging till I've done a speed test on prod. Will test the new optimization as well. Tests pass though, so I'm feeling confident about it

neilkakkar · 2021-06-28T11:05:24Z

So, there doesn't seem to be any issues when dealing with O(500k) events / query window. But I'm getting out of memory exceptions (using > 9.3 Gigs of memory) when dealing with O(500M) events / query window.

The expanding if condition though seems to be resolved using arraySum

EDsCODE

Given the tests, it seems this does work for now. The growing unions based on step number concerns me. We will want to think up a solution that doesn't grow like that. Even though our main funnel query also grows with step count, it adds outer query calculations whereas this would add more and more subqueries -> more and more data to be filtered.

However, if this is the best for now, we'll put it behind a feature flag anyway for preliminary testing

ee/clickhouse/queries/funnels/funnel_unordered.py

EDsCODE · 2021-06-28T23:43:46Z

ee/clickhouse/queries/funnels/funnel_unordered.py

+                    ) WHERE step_0 = 1"""
+
+            #  rotate entities by 1 to get new first event
+            entities_to_use.append(entities_to_use.pop(0))


I'm mainly curious how this rotation covers cases where events are scrambled and out of order. Also, the subquery UNION here does pose a risk because if you have many events in an "unordered funnel" we could end up in trouble with performance because all the filters would be applied to the subqueries separately

Very true.

So, the basic intuition is that we choose the first event, then choose any event that comes after it which matches our filters. So, just by switching the first event, we cover all cases where events may occur in any order.

It's not the rotation that's important, it's "what is the first event" that's important. Rotation felt like a good way to cover those bases.

Can you give an example of "scrambled and out of order" where you feel this doesn't work?

So, the basic intuition is that we choose the first event, then choose any event that comes after it which matches our filters. So, just by switching the first event, we cover all cases where events may occur in any order.

Yeah this makes sense. From the code itself it just seems like it's still looking for ordering after the first event, but if you're just rotating the first event then it should cover

Ah, it doesn't look for ordering, because I don't reuse the base funnel query (_get_steps_per_person_query), but just the inner event query

neilkakkar · 2021-06-29T09:34:39Z

Agree, this isn't optimal, there ought to be a better way, but I haven't managed to figure it out yet.

EDsCODE · 2021-06-29T20:57:41Z

Last thing that can be included in follow up is to add this class along the api path + a filter parameter that would account for the type of funnel ordering requested

ee/clickhouse/queries/funnels/base.py

ee/clickhouse/queries/funnels/funnel_event_query.py

…ered-step

Twixes · 2021-06-30T11:47:17Z

ee/clickhouse/queries/funnels/funnel_unordered.py

+        partition_select = self.get_partition_cols(1, max_steps)
+        sorting_condition = self.get_sorting_condition(max_steps)
+
+        for i in range(max_steps):


BTW what is our convention for numbering steps in queries? I'm not actually sure, but I saw that #4892 used 1-based indexing, while this is 0-based

step_i is zero based everywhere, while level_index is one based everywhere :/ - idea is to get everything to zero based, soonish. I wrote a comment mentioning this on the first Funnel PR - #4851 (comment)

Please feel free to merge if you're happy with it :) (comment if not lol)

Ah, I see now, I just misread #4892 a bit 👍

buwilliams and others added 28 commits June 18, 2021 08:48

wip: pagination for persons on clickhouse funnels

537bdb3

wip: added offset support for getting a list of persons; added suppor…

605f9de

…t for conversion window;

fixed mypy exception

a9a5f12

helper function to insert data for local testing

e952308

moved generate code into separate class for more functionality later

ceda12e

corrected person_distinct_id to use the person id from postgres

1a29fdb

minor corrections to generate local class along with addition of data…

1990907

… cleanup via destroy() method

reduce the number of persons who make it to each step

7daeaaa

moved funnel queries to a new folder for better organization; separat…

fba259e

…ed funnel_persons and funnel_trends_persons into individual classes;

Merge branch 'master' into funnel-persons-pagination-conversion-window

cc24758

funnel persons and tests

142e7b6

Merge branch 'funnel-persons-pagination-conversion-window' of github.…

df44123

…com:PostHog/posthog into funnel-persons-pagination-conversion-window

initial implementation

589e937

invoke the funnel or funnel trends class respectively

ac6d601

add a test

34d5bad

add breakdown handling and first test

b483277

add test stubs

9242414

remove repeats

3042e59

mypy corrections and PR feedback

474ba42

run funnel test suite on new query implementation

4abecaf

remove imports

62f2919

corrected tests

4fb5a43

minor test updates

74bfa1b

Merge branch 'funnel-persons-pagination-conversion-window' into funne…

0aa36f9

…l-step-query-new

correct func name

5c9dcd2

fix types

5df0cad

merge master

d7d2e60

unordered step and test

a9e9b7f

timgl temporarily deployed to posthog-pr-4868 June 24, 2021 14:49 Inactive

EDsCODE mentioned this pull request Jun 24, 2021

Sprint 1.27.0 2/2 - Jun 21 to Jul 2 (Funnels #1) #4765

Closed

remove breakdown, fix mypy error

b3fa339

timgl temporarily deployed to posthog-pr-4868 June 25, 2021 14:03 Inactive

Handle multiple same events in the funnel (#4863)

716e8af

* dedup + tests * deep equality. Tests to come * write test for entity equality * finish testing funnels * clean up comments

EDsCODE reviewed Jun 25, 2021

View reviewed changes

ee/clickhouse/queries/funnels/funnel_unordered.py Show resolved Hide resolved

neilkakkar added 2 commits June 25, 2021 16:23

Merge branch 'funnel-step-query-new' of github.com:PostHog/posthog in…

79cbea2

…to funnel-unordered-step

from O(2^N) to O(N)

6c4245f

timgl temporarily deployed to posthog-pr-4868 June 25, 2021 15:30 Inactive

neilkakkar mentioned this pull request Jun 28, 2021

Funnel with Strict Step Ordering #4890

Merged

7 tasks

Base automatically changed from funnel-step-query-new to master June 28, 2021 14:20

merge master

6d1f8f1

EDsCODE temporarily deployed to posthog-pr-4868 June 28, 2021 23:20 Inactive

EDsCODE reviewed Jun 29, 2021

View reviewed changes

add query intuition blurb

001a149

timgl temporarily deployed to posthog-pr-4868 June 29, 2021 12:11 Inactive

rm todo

1372f68

timgl temporarily deployed to posthog-pr-4868 June 29, 2021 12:14 Inactive

EDsCODE approved these changes Jun 29, 2021

View reviewed changes

Twixes requested changes Jun 29, 2021

View reviewed changes

neilkakkar added 2 commits June 30, 2021 10:16

Merge branch 'master' of github.com:PostHog/posthog into funnel-unord…

74e72cd

…ered-step

address comments

1bfa011

timgl temporarily deployed to posthog-pr-4868 June 30, 2021 09:28 Inactive

Twixes reviewed Jun 30, 2021

View reviewed changes

Twixes approved these changes Jun 30, 2021

View reviewed changes

Twixes merged commit 28d87ac into master Jun 30, 2021

Twixes deleted the funnel-unordered-step branch June 30, 2021 12:02

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Funnel Unordered Steps #4868

Funnel Unordered Steps #4868

neilkakkar commented Jun 24, 2021

EDsCODE left a comment

neilkakkar commented Jun 25, 2021

neilkakkar commented Jun 25, 2021

neilkakkar commented Jun 28, 2021

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neilkakkar commented Jun 29, 2021

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Twixes Jun 30, 2021

neilkakkar Jun 30, 2021

neilkakkar Jun 30, 2021

Twixes Jun 30, 2021

Funnel Unordered Steps #4868

Funnel Unordered Steps #4868

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neilkakkar commented Jun 24, 2021

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