I successfully upgraded to 9.1.2 from a database dump of a 8.22.0 installation – everything appeared in order. I then upgraded from 9.1.2 to 20.10.1 per your recommendation and now I see “There was an error loading data” retry messages when I click on an event. I let the upgraded instance run overnight just in case it was a migration issue, but after 8+ hours the same.
The contents of the database has gone from 62 GB down to 30GB.
For grins, I upgraded the 20.10.1 instance to 20.11.0; still same issue.
My PostgreSQL 9.6 DB instance is hosted on AWS and REDIS is utilizing Amazon’s Redis ElastiCache installation. This is the same configuration I’m successfully using on another Sentry instance which was rolling upgraded from 9.1.2 to 21.9.0.
9.1.2 → 20.10.1 → 20.11.0 logs => download
I believe my issue is the same issue reported here.