[Scaevolus]

Reading through their VLDB paper [1], Comdb2 appears to be a moderately scalable (up to dozens of nodes (?)) RDBMS with a strong emphasis on consistency and availability. Benchmarks show numbers comparable to Percona XtraDB (MySQL with a different storage engine), at ~2,000 writes/s and 2,000,000 reads/s against a 6 node server cluster. High availability and global sequencing is provided by using GPS clocks, similar to Spanner/Truetime.

Schema changes happen lazily, with old rows being rewritten on the next update, and a background job doing bulk rewriting.

Scalability: "While reads scale in a nearly linear manner as cluster size increases, writes have a more conservative level of scaling with an absolute limit. The offloading of portions of work (essentially all the WHERE clause predicate evaluations) across the cluster does help scale writes beyond what a single machine can do. Ultimately, this architecture does saturate on a single machine’s ability to process the low level bplogs."

This doesn't provide the horizontal scaling that Spanner does, CockroachDB aims at, or FoundationDB presumably has.

[1]: http://www.vldb.org/pvldb/vol9/p1377-scotti.pdf

[idibidiartists]

<< or FoundationDB presumably has >>

You mean FaunaDB?

[elvinyung]

FoundationDB was the proto-CockroachDB (or rather, CockroachDB is essentially a re-attempt at building FoundationDB). It was an early attempt at building a NewSQL database. (NewSQL per se, i.e. not counting parallel databases from the pre-NoSQL age, like Gamma [1], Volcano [2] and Grace [3], which share many of the same design principles.)

FoundationDB was acquhired by Apple, but its failure is generally attributed to a poorly-performing SQL layer: https://www.voltdb.com/blog/2015/04/01/foundationdbs-lesson-...

[1] http://pages.cs.wisc.edu/~dewitt/includes/paralleldb/ieee90....

[2] https://paperhub.s3.amazonaws.com/dace52a42c07f7f8348b08dc2b...

[3] https://pdfs.semanticscholar.org/a7f4/e4e6166dc683e7fa7d5b9e...

[Scaevolus]

No, FoundationDB which was posting some VERY impressive numbers before being acquired by Apple in March 2015.

Here they were doing 15M writes/s on 32 16-core servers, at a rate of 30,000 writes/s/core: http://web.archive.org/web/20150427041746/http://blog.founda...

FaunaDB managed 120,000 writes per second on 15 machines. https://fauna.com/blog/distributed-acid-transaction-performa...

(Yes, not equivalent benchmarks, but that's still a 50x difference in magnitude.)

[idibidiartists]

Down voted for asking a question? The system is definitely broke in such instances.

[acdha]

You worded the question in a way suggested you thought the previous commenter was wrong. That reads like either being a FaunaFB fanboy or not taking time to learn about Foundation, both of which will reliably attract downvotes. Had you worded it differently I doubt you'd be getting downvoted.

[idibidiartists]

So essentially the HN commenting UX is one of walking on egg shells.

[saghm]

I mean, a two-second Google could haven't shown you what FoundationDB was.