revori VS noria

I've implemented a RDBMS that supports this [1]. It handles joins, views (which are automatically materialized and incrementally updated), etc. It's memory only, and it doesn't support exotic stuff like recursive CTEs, but it does exactly what you're asking for. We used it in production successfully for frequently-updated real time data at the company where I used to work.

Notably, it uses persistent search trees such that each revision shares structure with the previous one, which makes diffing two closely-related revisions extremely efficient (just skip over any shared structure). Subscribers just receive a stream of diffs, with backpressure handled automatically by skipping over intermediate revisions. See [2] for a more detailed summary.

It also exposes revisions as first-class objects, which allows you to tag and diff them. Specifically, you can run arbitrary queries on both revisions and diffs. See [3] for examples.

It's no longer maintained, unfortunately. Someday I may revive it, perhaps adding support for spilling data that won't fit in memory to log-structured merge trees. I'd also rewrite it in a language like Rust, which will help flatten some of the more pointer-heavy data structures and reduce tail latencies. If anyone is interested in seeing that happen or helping out, let me know.

I'm really surprised this still isn't supported in mainstream DBMSes. The MVCC model in PostgreSQL seems particularly well suited to it.

[1]: https://github.com/ReadyTalk/revori

> Automatically managed, application-transparent, physical denormalisation entirely managed by the database is something I am very, very interested in.

Sounds a bit like Noria: https://github.com/mit-pdos/noria

It feels more than a little bit coincidental to call it Noria when https://github.com/mit-pdos/noria exists (and has been posted about here on HN)... especially with the whole bit about incrementally computing changes.

Is this similar in spirit to Noria?

https://github.com/mit-pdos/noria

I assume you have studied Noria? https://github.com/mit-pdos/noria

If you want to look how databases are implemented in rust try https://github.com/mit-pdos/noria

Only tangentially related, but I wondered what were the difference between ReadySet and Noria, and they address this exact question in their repository I'm really glad to know that the ideas behind Noria didn't die when Noria was abandoned after /u/jonhoo graduated.

:wave: Author of the paper this work is based on here.

I'm so excited to see dynamic, partially-stateful data-flow for incremental materialized view maintenance becoming more wide-spread! I continue to think it's a _great_ idea, and the speed-ups (and complexity reduction) it can yield are pretty immense, so seeing more folks building on the idea makes me very happy.

The PlanetScale blog post references my original "Noria" OSDI paper (https://pdos.csail.mit.edu/papers/noria:osdi18.pdf), but I'd actually recommend my PhD thesis instead (https://jon.thesquareplanet.com/papers/phd-thesis.pdf), as it goes much deeper about some of the technical challenges and solutions involved. It also has a chapter (Appendix A) that covers how it all works by analogy, which the less-technical among the audience may appreciate :) A recording of my thesis defense on this, which may be more digestible than the thesis itself, is also online at https://www.youtube.com/watch?v=GctxvSPIfr8, as well as a shorter talk from a few years earlier at https://www.youtube.com/watch?v=s19G6n0UjsM. And the Noria research prototype (written in Rust) is on GitHub: https://github.com/mit-pdos/noria.

As others have already mentioned in the comments, I co-founded ReadySet (https://readyset.io/) shortly after graduating specifically to build off of Noria, and they're doing amazing work to provide these kinds of speed-ups for general-purpose relational databases. If you're using one of those, it's worth giving ReadySet a look to get these kinds of speedups there! It's also source-available @ https://github.com/readysettech/readyset if you're curious.

It seems similar to MIT's Noria [1]

> Noria is a new streaming data-flow system designed to act as a fast storage backend for read-heavy web applications based on Jon Gjengset's Phd Thesis, as well as this paper from OSDI'18. It acts like a database, but precomputes and caches relational query results so that reads are blazingly fast. Noria automatically keeps cached results up-to-date as the underlying data, stored in persistent base tables, change. Noria uses partially-stateful data-flow to reduce memory overhead, and supports dynamic, runtime data-flow and query change.

[1] https://github.com/mit-pdos/noria

Materialize is really neat, also checkout https://github.com/mit-pdos/noria. It inverts the query problem and processes the data on insert. Exactly like what most applications end up doing using a no-sql solution.