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Comment by devbug | Hacker News Reader

Do you mind detailing your experience with Dataomic? We're looking at ways to store 6-ary tuples (quadstore + temporality of existence and temporality of observation) of facts and build indices on top of them. I'm hesitant to move to (relatively) obscure data store without a really good idea of where that puts us.

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We didn't get terribly far down the road with Datomic. Management/administration of the DB was not for the faint of heart. (At the time the docs were simply terrible, maybe they are better now?) We would see data corruption/loss as well. We weren't doing anything terribly complicated with it, and data loss doing the simplest things was unacceptable. (It's entirely likely we were the cause of the data loss somehow, but we followed the guides and did nothing crazy or weird). So anyways, we just threw it out almost immediately.

Conceptually it wasn't really a fit with the team or our application either. The query model and direct reading from the storage medium seemed silly - why not just use underlying storage medium directly for everything? (Besides, now you have to administer both Datomic and Cassandra/Oracle whatever) Not worth it for the obtuse query approach and limited value of "never forgetting" imo :)

Direct use of the storage medium for everything would negate the advantages Datomic offer. The beautiful part of Datomic is that you can perform an expensive query without having any effect on other peers. Since Datomic also stores datoms in blocks, the n+1 problem is reduced as well. Another cool thing is that for unit-testing, you can just disconnect Datomic from the storage medium, and run everything in memory. Datomic requires writes to be synchronised, which is why you can't go directly through the underlying storage medium for write cases.

While I personally would love to use Datomic for just about everything. The fact that I need at least three machines going for the simplest app (1 actual database, the peer and the transactor) and that those machines can't be the cheapest machines (you need enough ram to store datoms in a cache on the client, or things will be slow), Datomic is something I can rarely afford in practice.

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