Apache Pegasus - A horizontally scalable, high-performance key-value store

[seeekr]

Note that this seems to be a relatively old project, first commits from 2015. The project seems active, but most of the work seems to have been done around its inception, with some significant activity from 2020 onwards. Speculation/interpretation: So this might be a project that was used internally by some company, but perhaps not any more, and they've decided to open-source it at some point (2017-2018?) because some folks were/are still excited about it and want to keep developing it.

This might explain some of the "why yet another RocksDB-based KV store?" line of questioning.

[pas]

> yet another RocksDB-based KV store

Aaah, there was a super informative talk about the different databases at Facebook, most of them built on RocksDB, with different trade offs. (And I can't find the video :((((( )

Anyway, it makes sense to have yet another it if serves a different purpose. Eg. for read-heavy workloads (caches, serving user feeds, whatever), or write-heavy (monitoring, storing that sweet sweet tracking juice that then gets read once or twice while building the recommendation models), small or large blobs, latency requirements, HA/consistency requirements, how complicated queries are going to be, does it support secondary indices or not, etc.

[l2dy]

Pegasus was open-sourced by Xiaomi, and is still used internally according to https://apachecon.com/acasia2022/sessions/ai-1125.html.

Source: https://www.zhihu.com/question/66719537/answer/245270169 (in Chinese)

[xani_]

Apache foundation is retirement home for projects so it checks out

[tmikaeld]

Will be interesting to see the benchmarks!

There's a lot of KV engines that uses RocksDB now, like CockroachDB (Forked into PebbleDB though), YugabyteDB and TiDB.

Those are all many times slower than Redis though, so having a middle-ground aimed to be similar to Redis, that doesn't eat all RAM, is very exciting!

[hknmtt]

because you are comparing in-memory store with permanent storage. many kvdb can be run from memory if needed.

[c0balt]

Isn't TiDB built on top of TiKV?[0]

[0]: https://github.com/pingcap/tidb

[yla92]

> Those are all many times slower than Redis though

I'd appreciate if there any links/doc that I could look into to learn more about this?

[endisneigh]

Be curious to see differences between this and FoundationDB.

[scary-size]

Is it me or are most of the docs only available in Chinese?

[tmikaeld]

It says it's being translated at the moment.

[spockz]

Why yet another key value store?

[sidcool]

KV stores are a complex topic and research continues. Each new tool comes with its own set of trade offs. It would help to go through the documentation.

[hk1337]

This seems very interesting and I am peaked but the documentation and web page is lacking a lot to tell me what it is and how it's intended to be used. I know it's a key value store and it's supposed to be fast but that's it.

[hasperdi]

Anyone using this in production? If so, how do you find it, is it good?

[pknerd]

Another key/Value store system. There are already like RocksDB, LevelDB and many others!

[sofixa]

This one is distributed though, using RocksDB as the underlying storage.

[truth_seeker]

why would I choose it over TiKV or RIAK ?