Neki – Sharded Postgres by the team behind Vitess

Post by eatonphil » Tue, Aug 12, 2025, 7:30 PM UTC

vladich wrote: post #40

eatonphil wrote: post #13

Earlier quoted context omitted.

Who isn't? Cockroach rewrote Postgres in Go. CedarDB rewrote Postgres in C++. And then to lesser degrees you've got Yugabyte, AlloyDB, and Aurora DSQL (and certainly more I'm forgetting) that only replace parts of Postgres.

Both Cockroach and CedarDB didn't rewrite anything, they built stuff from scratch. Just used the same client protocol. There are a bunch of other unrelated databases using Postgres protocol btw.

Post by lmz » Wed, Aug 13, 2025, 12:55 PM UTC

atombender wrote: post #35

lmz wrote: post #31

Earlier quoted context omitted.

By MVCC you mean the kind of MVCC that keeps old versions in the same space / requires vacuum? Because I'm pretty sure Oracle also does multiversioning using their undo log / rollback segment.

Calling undo/redo MVCC isn't really accurate. The whole point of Postgres' style of MVCC is that updates leave the original rows unmodified, which allows concurrent transactions to read them without extensive locking or redirection. In Oracle's database engine, when transaction A updates a row, it begins by reading the old row, updating it in-place, and adding the old row to the undo log. The heap row has a header wi…