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RxDB – a real-time database on top of PouchDB

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Re: RxDB – a real-time database on top of PouchDB

#21

Post by adav »

typingmonkey wrote: post #13
lukevp wrote: post #12

Earlier quoted context omitted.

That’s great to hear! Are you pubkey? If so you should put that in your profile! I hope you know that I think RxDB is a great lib and going in a good direction! I recommended it to the Supabase team a couple weeks ago. I am less long PouchDB, it feels like an old generation of this tech and not the best way to solve these problems in 2020.

I updated my profile. I do not know supabase, is it similar to hasura? They spend quite some effort [1] to make the RxDB graphql replication working with their backend. Maybe supabase can use a similar wrapper over GraphQL. [1] https://hasura.io/learn/graphql/react-rxdb-offline-first/int...

Cool! I was just thinking that RxDB + Hasura would be pretty nifty for an offline-first MVP and here the legwork has already been done :)

Re: RxDB – a real-time database on top of PouchDB

#23

Post by typingmonkey »

b1ackb0x wrote: post #22

But is it really "realtime"? I thought something should have consistent millisecond or even microsecond latencies to be called realtime, but it's probably not possible for JavaScript application.

Yes and no. Read "realtime" not like "realtime computing" but like a marketing keyword introduced by firebase which means something like live-replication. https://firebase.google.com/docs/database?hl=en

Re: RxDB – a real-time database on top of PouchDB

#24

Post by typingmonkey »

remon wrote: post #19

How is this different from Firebase RTDB? And perhaps more importantly, does it address the scalability and consistency issues associated with Firebase RTDB? Google introduced Firestore to Firebase specifically because RTDB has limited usability for larger real world applications that go beyond "sync device state to DB". Even the offline first paradigm is fundamentally flawed in general and certainly when it comes to…

There are many mobile apps out there which work great and are offline first. For example the whatsapp client. So saying it is "fundamentally flawed" sound weird to me.

I have no deep knowledge of Firebase RTDB so I cannot do any comparison on that point.

Re: RxDB – a real-time database on top of PouchDB

#25

Post by joshribakoff »

b1ackb0x wrote: post #22

But is it really "realtime"? I thought something should have consistent millisecond or even microsecond latencies to be called realtime, but it's probably not possible for JavaScript application.

If you wanted to be pedantic, nothing is real-time not even what you see with your eyes due to photon latency. The word is clearly being used colloquially

Re: RxDB – a real-time database on top of PouchDB

#26

Post by IggleSniggle »

lukevp wrote: post #11
diegoperini wrote: post #6

Looks amazing. I always loved how Rx composes with IO on the client side, this looks like the missing half. I hope it survives. For people who are soon to be choosing a stack for their projects, please be careful. In 2015, we adopted RethinkDB which had very similar ambitions as RxDB and was open source. Unfortunately, RethinkDB is now abandoned (kinda). Many promising subscribe-able databases are still experimental.…

I agree, I think the move to a more mature state management on the client in general sort of obviated the needs for these databases. Eg if you’re using redux, or mobx, or Apollo, you can cache offline data directly in your state tree, and can define validation functions locally on state transitions to keep your data valid with your business rules while it’s offline. I still feel there’s a space for this tech, but tha…

I haven't tried this because I don't need persistent client state, but couldn't you just take your redux or whatever state tree and shove it into a persistent storage, and restore on load?

Re: RxDB – a real-time database on top of PouchDB

#27

Post by MuffinFlavored »

lukevp wrote: post #9

The concept or RxDB, being able to iterate observables of your change stream, is great. Centering on schemas and typescript is as well. The broadcast channel based leader election also solved the common issue with Pouch where you can’t respond to real-time changes and update your UI if a separate tab was watching too. It’s wise of them to also support pulling data from GraphQL. I built the first version of NoteBrook…

> The concept or RxDB, being able to iterate observables of your change stream

Why can't this be done with a thin wrapper around Postgres pub/sub + triggers?

Re: RxDB – a real-time database on top of PouchDB

#28

Post by joshribakoff »

remon wrote: post #20
diegoperini wrote: post #6

Looks amazing. I always loved how Rx composes with IO on the client side, this looks like the missing half. I hope it survives. For people who are soon to be choosing a stack for their projects, please be careful. In 2015, we adopted RethinkDB which had very similar ambitions as RxDB and was open source. Unfortunately, RethinkDB is now abandoned (kinda). Many promising subscribe-able databases are still experimental.…

Subscribe-on-update databases are, almost by definition, problematic to use at scale as a generic storage solution. The fundamental problem is that they do not solve many real world problems efficiently enough to warrant the significantly higher running cost. Of course there are exceptions but it'll be hard to launch a MongoDB type of product that uses a subscription only model (see Firebase RTDB and its problems and…

I think you’re oversimplifying it. I was on teams that participated in architecture design for this stuff at Twitch. If we had 100,000s of clients polling at the same moment, that would absolutely knock over the server, the canonical “stupid easy” fix is to add jitter, which can be done on either client or server.

In fact the pull based approach is doing work all the time to process all the polling. A push based approach only does work when needed (when data changes).

I’m not saying it’s not new or hard to scale. I’m just saying objectively that push based is more efficient at least in terms of raw data sent down the wire

Re: RxDB – a real-time database on top of PouchDB

#29

Post by thomasfedb »

lukevp wrote: post #9

The concept or RxDB, being able to iterate observables of your change stream, is great. Centering on schemas and typescript is as well. The broadcast channel based leader election also solved the common issue with Pouch where you can’t respond to real-time changes and update your UI if a separate tab was watching too. It’s wise of them to also support pulling data from GraphQL. I built the first version of NoteBrook…

If you could document your experience with Pouch/Couch that would be excellent. I've considered using the stack for a offline-first SPA but the curve seem so steep, particularly the database creating, proxying, etc required to make Couch behave with many clients.

Re: RxDB – a real-time database on top of PouchDB

#30

Post by faizshah »

typingmonkey wrote: post #17
k__ wrote: post #16

Earlier quoted context omitted.

Ah good to know you already looked into that :D Thanks for the info!

Yes I did :D . I wrote a full master thesis about the differences and tradeoffs of these "realtime" databases.

Is it available online? Sounds interesting.
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