[simtel20]

It's not simply revision history, it's a complete record of everything with time, without re-architecting your data or app. IIRC datomic structures your data so that all transactions and state have a time dimension so you can go forward or back in time trivially (no special query, no temporal sql, etc.)

[motogpjimbo]

What happens when you have a legal obligation to delete or anonymise data for some reason?

[fulafel]

There's https://docs.datomic.com/pro/reference/excision.html - but like in other data models you also might choose to not store sensitive infromation like PII in cleartext in the main DB at all. At least in earlier versions excision wasn't supported in the Datomic Cloud version.

[lebski88]

Excision still isn't supported for cloud, it is / was on their plan but there was never any movement in that direction.

[fulafel]

I wonder if this is related to lack of guarantees about actual data erasure on delete in the backing storage. A lot of users probably don't take this into account when building on top of cloud storage servies.