Bug: Events API - missing records in paginated results due to duplicate timestamps #34143
Description
Bug Description
Bug description
The events API (/api/projects/:project_id/events), and possibly other endpoints, may miss records from paginated results where there are duplicate timestamps in the results.
This is caused by the next key on the response object using before with a timestamp to define the next page of results - e.g. "next":"https://us.posthog.com/api/projects/:project_id/events/?before=2025-06-25T09%3A58%3A42.921000%2B00%3A00". If the before timestamp is seen on multiple events across a page boundary, then the events that should have appeared at the start of the next page of results are skipped.
We do appear to use offset based pagination elsewhere.
Using the query API to fetch events with offset based pagination can be used as a workaround for this issue.
Additional context
From: https://posthoghelp.zendesk.com/agent/tickets/33156
Debug info
Kind: bug
Target area: data_management
Report event: http://go/ticketByUUID/a3567211-4b58-44fd-9ab1-a07f9e33fcc9
Session: https://us.posthog.com/project/sTMFPsFhdP1Ssg/replay/0197a2e6-fdd7-7219-89f6-d13f2218fd75?t=10036
Exceptions: https://us.posthog.com/project/2/error_tracking?filterGroup=%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22type%22%3A%22AND%22%2C%22values%22%3A%5B%7B%22key%22%3A%22%24session_id%22%2C%22value%22%3A%5B%220197a2e6-fdd7-7219-89f6-d13f2218fd75%22%5D%2C%22operator%22%3A%22exact%22%2C%22type%22%3A%22event%22%7D%5D%7D%5D%7D
Location: https://us.posthog.com/project/184456/activity/explore#q=%7B%22kind%22%3A%22DataTableNode%22%2C%22full%22%3Atrue%2C%22source%22%3A%7B%22kind%22%3A%22EventsQuery%22%2C%22select%22%3A%5B%22*%22%2C%22event%22%2C%22properties.source%22%2C%22properties.type%22%2C%22timestamp%22%5D%2C%22orderBy%22%3A%5B%22timestamp%20DESC%22%5D%2C%22after%22%3A%22all%22%2C%22modifiers%22%3A%7B%22usePresortedEventsTable%22%3Atrue%7D%2C%22properties%22%3A%5B%5D%7D%2C%22propertiesViaUrl%22%3Atrue%2C%22showSavedQueries...&
Persons-on-events mode for project: person_id_override_properties_on_events