Realm Mobile Platform – Realtime Sync Plus Fully Open Source Database

Post by striking » Tue, Sep 27, 2016, 5:57 PM UTC

janl wrote: post #48

timanglade wrote: post #7

Earlier quoted context omitted.

Hi, former Apache CouchDB guy, former Cloudant employee, and former Realm employee here… I (still) love CouchDB but at the end of the day I think its sync is a better fit for server-to-server or web client-to-server use-cases, not mobile-to-server. There’s tons of stuff CouchDB sync doesn’t support that end up being a huge problem with mobile apps… Here are the top 3 things Realm adds in my opinion: great client-side…

How is "conflict-free sync" done? The usual approach is last-write-wins, which is just a euphemism for "randomly losing user data", or CRDTs or Operational Transforms, which severely limit the data models one can sync. I'm happy to learn about a silver bullet here.

Post by bigfish24 » Tue, Sep 27, 2016, 6:13 PM UTC

janl wrote: post #48

timanglade wrote: post #7

Earlier quoted context omitted.

Hi, former Apache CouchDB guy, former Cloudant employee, and former Realm employee here… I (still) love CouchDB but at the end of the day I think its sync is a better fit for server-to-server or web client-to-server use-cases, not mobile-to-server. There’s tons of stuff CouchDB sync doesn’t support that end up being a huge problem with mobile apps… Here are the top 3 things Realm adds in my opinion: great client-side…

How is "conflict-free sync" done? The usual approach is last-write-wins, which is just a euphemism for "randomly losing user data", or CRDTs or Operational Transforms, which severely limit the data models one can sync. I'm happy to learn about a silver bullet here.

Post by pfraze » Tue, Sep 27, 2016, 6:15 PM UTC

astigsen wrote: post #35

nolanl wrote: post #31

Earlier quoted context omitted.

(I also work on PouchDB.) For "conflict-free sync," according to the docs, this appears to be last-write-wins along with a special case for deletes: https://realm.io/docs/realm-object-server/#conflict-resoluti... . (Incidentally Couch/Pouch also has a special case for deletes, but it does the opposite behavior by default – deletions lose to updates.) There's also some language in here about how "insertions in lists a…

Realms approach to conflict resolution is very different from what you see in products like Couch. Realm is an _object_ database, so in contrast to document databases where conflict resolution happens very coarse grained at the document level, in Realm it happens at the object level (and actually all the way down into individual properties). This essentially means that the entire object graph is treated as one big CR…

Post by andkon » Tue, Sep 27, 2016, 6:47 PM UTC

janl wrote: post #47

andkon wrote: post #26

Earlier quoted context omitted.

I think you're misunderstanding what "Native Models" means in the context of iOS work. Saying that a database uses JSON immediately, to many ios devs, recalls years of writing very fragile json serialization code. Looking through CouchDB's iOS example apps confirms that yes, basically everything that isn't a string or int has to be serialized into JSON. That's a pretty enormous annoyance, and incorporates a lot of ad…

CouchDB doesn't have any iOS code, are you perhaps referring to Couchbase?

Post by janl » Tue, Sep 27, 2016, 7:39 PM UTC

bigfish24 wrote: post #53

janl wrote: post #48

Earlier quoted context omitted.

How is "conflict-free sync" done? The usual approach is last-write-wins, which is just a euphemism for "randomly losing user data", or CRDTs or Operational Transforms, which severely limit the data models one can sync. I'm happy to learn about a silver bullet here.

It is true that most Operational Transform systems have limited data model support, but that's an area Realm is quite unique on. The Realm Mobile Platform supports all of Realm database's current data types, such as native support for links and ordered lists. Also have plans for much more including: substring changes, counters and sets.