Ask HN: What could a modern database do that PostgreSQL and MySQL can't

Re:Ask HN: What could a modern database do that PostgreSQL a... by mirekrusin on Sunday September 05, 2021 @01:38PM (#28426091)

true, thanks for pointing out, but this is a bit cheating isn't it? ie. atomic transactions cross shards flip over, right? it's basically ergonomic equivalent of just using multiple databases?

[ Parent | on HN ]

Re:Ask HN: What could a modern database do that PostgreSQL a... by eis on Sunday September 05, 2021 @04:33PM (#28427512)

Not 100% sure what you mean by flipping over (fail?) but at least in CRDB you can of course do cross shard transactions. They wont be as fast as a transaction that can be completely handled by a single leader but it works fine and is transparent to the client.

[ Parent | on HN ]

Re:Ask HN: What could a modern database do that PostgreSQL a... by radicalbyte on Sunday September 05, 2021 @05:12PM (#28427849)

You move over into the world of distributed transactions, which can be really expensive.

Thankfully sharding works great for a large number of applications (or in other cases you can accept eventual consistency).

[ Parent | on HN ]

Re:Ask HN: What could a modern database do that PostgreSQL a... by GeneralMayhem on Monday September 06, 2021 @03:45AM (#28431414)

Cross-shard transactions will use some sort of two-phase commit protocol internally. They still work just fine (the extra complexity is transparent to the client), but with somewhat worse performance. Most of the difficulty/expertise involved in using such systems optimally is in designing your schema and access patterns such that you minimize the number of cross-shard transactions.

[ Parent | on HN ]