Can anyone give concrete examples of datasets that are better suited for a graph database and why?
Cayley – An open-source graph database
31–40 of 71 posts
Re: Cayley – An open-source graph database
#32What exactly is this? The GitHub page speaks of different backends, and those appear to just be databases or key-value stores in themselves (e.g, Postgres and Bolt).
Is Cayley basically a query rewritter, that is it has some tables in the backend and when queried, Cayley then goes to the "real" (for lack of a better word) database? Cayley's query language might be more full featured, but it isn't a storage mechanism in itself?
There are two things from that:
1. There is no way for Cayley to take the graph structure of the data into account when laying it out on disk or when executing the query. Is this the long-term decision, or is this just a stop-gap until a storage mechanism can be done?
2. This would seem to imply that the abstraction layer from Cayley to the backend storage would be relatively slim. How difficult is it to add another storage driver for another SQL database or for one with a custom query language?
Another thing I noticed:
> query -- films starring X and Y -- takes ~150ms
Even on two year old hardware that seems dog slow - less than 7 queries a second - for a very simple query.
Re: Cayley – An open-source graph database
#33Can anyone give concrete examples of datasets that are better suited for a graph database and why?
Anything Social. Product or Person hierarchies. Network datasets. Ancestry (genetic or data), etc.
They are better suited for Graph Databases because the queries tend to be many joins traversing paths both deep and wide.
Re: Cayley – An open-source graph database
#34I can't understand how to use the query language. It all seems so magical! I tried building something with Cayley once but couldn't fetch all the data I wanted in a single query, or didn't know how to, then got frustrated and deleted everything.
Which of the three query languages are you having trouble with? All of them? MQL has been around a long long time (2006). Gizmo is new but based on & very similar to Gremlin (2009). GraphQL is the newest (2015). Did you try them all? Or is one in particular rough?
Re: Cayley – An open-source graph database
#35Maintainer here, good to see Cayley on HN again :) We've got a lot of new features on master, (GraphQL support, Gephi interfaces, Recursive iterators, etc) and are cutting a release next week. Active work in the coming releases on tightening down the indexing and really bringing it into prod. EDIT: Feel free to join the new Slack or the Discourse mailing list/discussion board!
What's the difference between Cayley and Neo4J?
Neo4j has control end to end. Cayley storage is handled by other databases. You can say one is a graph database and the other is a graph library on top of another database. Same as Titan now Janus.
Re: Cayley – An open-source graph database
#36What exactly is this? The GitHub page speaks of different backends, and those appear to just be databases or key-value stores in themselves (e.g, Postgres and Bolt). Is Cayley basically a query rewritter, that is it has some tables in the backend and when queried, Cayley then goes to the "real" (for lack of a better word) database? Cayley's query language might be more full featured, but it isn't a storage mechanism…
You can't derive rate from latency alone. The query might be IO bound. If that's the case, you can run queries concurrently.
Re: Cayley – An open-source graph database
#37What exactly is this? The GitHub page speaks of different backends, and those appear to just be databases or key-value stores in themselves (e.g, Postgres and Bolt). Is Cayley basically a query rewritter, that is it has some tables in the backend and when queried, Cayley then goes to the "real" (for lack of a better word) database? Cayley's query language might be more full featured, but it isn't a storage mechanism…
You can't derive rate from latency alone. The query might be IO bound. If that's the case, you can run queries concurrently.
I tend to care more about latency than throughput. FedEx has the best throughput in the world if you can wait a couple days.
True though. I'm guessing with a latency number like that, the throughput is pretty bad too.
Re: Cayley – An open-source graph database
#38Anyone use Cayley in prod? An old job used Neo4j, and the graph concept was great for specific use cases. As a lightweight graph store, Cayley was really exciting when it came out, but I haven't had a need for it since I left that job. It strikes me as really well made, and I'd love to hear any war stories.
Tried to use it in production a couple of years ago hosting a mirror copy of Freebase with mixed results: - There were a couple of issue loading the data that we fixed and contributed back the patch - Loading the data was really slow, and it got slower every time a new entry was added (Loading the full freebase dump required 1 week on a very beefy machine with SSD. Used LevelDB) - Then the queries were relatively slo…
Benchmarks for loading freebase data in Cayley vs Dgraph.
https://discuss.dgraph.io/t/differences-between-dgraph-and-c...
Dgraph was 10X faster.
Re: Cayley – An open-source graph database
#39Earlier quoted context omitted.
You can't derive rate from latency alone. The query might be IO bound. If that's the case, you can run queries concurrently.
I tend to care more about latency than throughput. FedEx has the best throughput in the world if you can wait a couple days. True though. I'm guessing with a latency number like that, the throughput is pretty bad too.
Exactly what https://dgraph.io is built for. Low latency, high throughput.
Re: Cayley – An open-source graph database
#40Earlier quoted context omitted.
I tend to care more about latency than throughput. FedEx has the best throughput in the world if you can wait a couple days. True though. I'm guessing with a latency number like that, the throughput is pretty bad too.
Exactly what https://dgraph.io is built for. Low latency, high throughput.
Looks interesting.
That semi-declarative query language is hideous though. Reminds me of attempts to make XML into a programming language.