Re: JanusGraph meetup topic discussion - graph OLAP & algorithms

Ted Wilmes

Hey Dylan,
Thanks for the links. That's a promising set of projects. I think a brief survey of OLAP graph engines that may be applicable to JG users would be very interesting. In addition to looking at alternative OLAP engines, I think the question of integration is an interesting one. For example, TP Spark pulls data directly out of JG. I find this attractive from the standpoint of not having to maintain a mirror image of the OLTP graph, but we pay a large performance penalty. Alternatively, a mirror image OLAP graph can be maintained, likely using the same change feed that JG ingests. A third, alternative, that may be feasible using the in-memory storage backend and the darker corners of the JG code base, the FulgoraGraphComputer, could possibly be made to work in a zero-copy fashion. Anyway, not as exciting as the selection/development of the OLAP engine itself, but I think the integration will play a big part in ease of use and adoption.


On Fri, Feb 12, 2021 at 4:49 PM Dylan Bethune-Waddell <dylan.bethune.waddell@...> wrote:
Hi Ted,

Great idea Ted. Wanted to mention KatanaGraph (website, github). It's basically a port of this codebase called Galois (website, github). Appears to be a group of UT Austin researchers taking their impressive results (paper) solving various OLAP graph computing problems into open source (3-Clause BSD License). From what I've gathered poking around the new codebase vs. old, and the demo server you can launch a notebook on, they aim to commercialize the distributed GPU aspect of Galois after getting it production ready as katana "enterprise". The guts of it exist in the Galois codebase and they do refer to it - could be a good conversation to have in the JanusGraph community.

Seems like KatanaGraph and cool stuff like spark-rapids are all using the Apache Arrow format, might be an integration to consider. Another interesting project is the GraphBLAS, which is a spec but now has concrete implementations including this one which is from a "competitor" to KatanaGraph, gunrock. IIRC the gunrock direction-optimized BFS code is faster on power-law graphs than the implementation of BFS in katana/galois, which might be Interesting in terms of how Gremlin expects to do it's OLAP traversals.


On Thu, Feb 11, 2021 at 11:51 AM <hadoopmarc@...> wrote:
Hi Ted,

Most probably you recognize my nickname from the answers I provided on this user forum on OLAP attempts with JanusGraph. I also co-authored:

showing the need to test the scalability of graph algorithms.
I am interested to participate in the meeting and I am open to suggestions where contributions are most needed (no new material, so part of panel or presenting old material).

Best wishes,     Marc

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