retention comes with insufficient warnings
it is well-known to corrupt the database via insufficient cache invalidation, yet the config documentation almost recommends it. It needs a big health warning
cf https://github.com/matrix-org/synapse/issues/13476
What happens if I decide (because of mentioned risk) to remove retention: enabled: true from configuration and many rooms in my HS have retention configured? Is it safe? Please add that to docs also.
And are there different risks if I delete history e.g. from yesterday or 3 years ago?
What happens if I decide (because of mentioned risk) to remove retention: enabled: true from configuration and many rooms in my HS have retention configured? Is it safe?
I believe that's fine, yes.
Please add that to docs also.
Pull requests to improve the documentation are always welcome :innocent:
And are there different risks if I delete history e.g. from yesterday or 3 years ago?
Yes, there are different risks in the sense that you're less likely to hit one of the problematic races by deleting history from 3 years ago than by deleting history from yesterday.