Field Note #31. On "Problems with Distributed Databases"

Source: Coral Health, "Why Blockchains Don't Suck, and the Perils of Distributed Databases," avail. online (Aug. 7, 2019)

THE ONE-LINER.
"Don’t just use a blockchain because it’s the cool thing to do... more importantly, don’t just use a distributed database because it’s the cooler thing to do." (Id.). See also Field Note 28 (On "Blockchain, not Slow Database").

THE CRITIQUE.
Status quo solves blockchain use cases via distributed databases.

THE RESPONSE.
Distributed databases aren't simple; stop oversimplifying them.

• Distributed databases that promise scalability suffer from data consistency.  Send/receive between distributed nodes can be unreliable.
• Conflict resolution is problematic for distributed databases.
• Relational "ACID" databases have weak levels of isolation as a tradeoff for scale, failovers are problematic, and timestamping can't be relied upon.
• NoSQL / MongoDB uses sharding but is based on eventual consistency
• No ability to handle malicious nodes given centralized administration of distributed databases

THE DETAILS...