Hi Brad,

Can you post the profile result of both queries? You can retrieve profile results by adding `.profile()` to the end of your query.

Best,
Boxuan

How fast is immediately?  A well dimensioned cassandra or scylladb cluster (with its own block cache!) should be able to serve requests at the ms level.

https://www.scylladb.com/2017/09/18/scylla-2-0-workload-conditioning/

You only run into trouble with queries that ask for tens or hundreds of vertices, but you can ask if it is reasonable to be realtime at the ms level for such large queries.

Best wishes,     Marc

Hi Matt,

Adding to what I stated above about independent composite indices for separate graphs on the same storage backend, the issue turns out to more nuanced for mixed indices on an indexing bakend, see the recent question:

https://lists.lfaidata.foundation/g/janusgraph-users/topic/88879391

I though it useful to add it to this thread too.

Marc

PS Good to hear that JanusGraph can possibly support your usecase!

I had to try for myself and, indeed, the ref docs are not very clear about this. In order to give the second graph a separate, independent mixed ndex
you have to adapt the properties file for the second graph like (in this case a variant on janusgraph-cql-es.properties):

gremlin.graph=org.janusgraph.core.JanusGraphFactory
storage.backend=cql

storage.hostname=127.0.0.1
storage.cql.keyspace=janusgraph2

cache.db-cache = true
cache.db-cache-clean-wait = 20
cache.db-cache-time = 180000
cache.db-cache-size = 0.25

index.search2.backend=elasticsearch
index.search2.hostname=127.0.0.1
index.search2.index-name=janusgraph2

After loading the graphs you can check against the indexing backend:

$ curl http://127.0.0.1:9200/_cat/indices
green  open .geoip_databases    O7iNY_U4Sui1yfFontk3lA 1 0 42 0 38.8mb 38.8mb
yellow open janusgraph_edges    OfbruO3BRIOPLMVYwUSWRw 1 1  6 0  4.4kb  4.4kb
yellow open janusgraph_vertices EGmMEvXuQXiIxTasEnSIDw 1 1  6 0  3.8kb  3.8kb
yellow open janusgraph2_vertices  UQITuYsnTA2d2J8MyyblLA 1 1  6 0  3.8kb  3.8kb
yellow open janusgraph2_edges     d1ZOPXVSTze0HQkg_vEz1A 1 1  6 0  4.4kb  4.4kb

Also, if you use the GraphOfTheGodsFactory for testing with two graphs, you have to use it like:
gremlin> GraphOfTheGodsFactory.load(graph1, 'search', false)
gremlin> GraphOfTheGodsFactory.load(graph2, 'search2', false)

I did not check if this can work for the ConfigurationGraphFactory, but if you find this impossible either of us should report an issue
for it (together with extending the ref docs with the above) .

Best wishes,    Marc

Hello,

I need to execute Janusgraph traversals, using a Union step, which contains multiple 'has' steps, each of which tests an indexed property for equality to a value.  Prior to the Union step, there is another 'has' step, which also tests an indexec property.

For example:

    g.V().has('indexed-prop1', 'value1').union(has('indexed-prop2', 'value2'), has('indexed-prop3', 'value3'))

How can I verify whether or not the traversal is using indices 'indexed-prop2' and 'indexed-prop3'?  I suspect that it is not.  The traversal seems to take a long time to run; however, when I simplify the traversal, by having only one 'has' step within the union, it runs very quickly.

What is the best way to execute this type of traversal.  My application is written in Java.

Thanks in advance,
Brad

Hi Marc, I follow what you're saying but will point out it doesn't have to play out to exabytes. Reason is that IDs are non recyclable and there are losses due to bulk load reservations and deletions. I'm looking at JG from a 3store pov where a trillion triples isn't out of reach when it comes to knowledge graphs. Hearing that limits are scoped to the graph makes it much more palatable. 

thx, matt

Hi! I've setup elastic search for configurationGraphFactory and Bigtable, using below configurations

Configurations:

In a multi node Janusgraph cluster, data modification done from one instance does not sync with others until it reaches the given expiry time (cache.db-cache-time)

As per the documentation[1] it does not recommends to enable database level cache in a distributed setup as cached data does not share amoung instances.

Any suggestions for a solution/workaround where i can see the data changes from other JG instances immediately and avoid stale data access ?

[1] https://docs.janusgraph.org/operations/cache/#cache-expiration-time

Hi Matt,

Correct, but you should really try this out and see for yourself. Also check the janusgraph db folder after having created two graphs and see what files are created.

Per graph, but you realize that these number would require exabytes of storage?

Best wishes,   Marc

Created https://github.com/JanusGraph/janusgraph/issues/2966 to track the streaming feature request.

--

Hi Umesh,

No, it is not clear at all whether the issue and cassandra-4.0 are related, but generally it is not useful to report bugs regarding unsupported configurations. To dig deeper, I would be curious about:
 - can you log the vertex id and label for the transactions that fail and  can you make another transaction fail with these values?
 - the stracktrace suggests that the issue is in querying the graph schema. Can you trigger the exception by manually querying the graph schema for the vertex labels involved?

Best wishes,     Marc

--

Hi Umesh,

On the first line of your first post you state that you use cassandra-4.0. However, support for cassandra-4.0 is still an open issue:

https://github.com/JanusGraph/janusgraph/issues/2325
https://docs.janusgraph.org/changelog/#version-compatibility-matrix

It is confusing, indeed, that the driver version is 4.13.0, but this is correct, see:
https://github.com/JanusGraph/janusgraph/blob/v0.6.1/pom.xml

Best wishes,    Marc

--

Hi Marc, just to be clear.

If I create Graph A and build an index on Vertex P via something like:

JanusGraphManagement mgmt = graph.openManagement();
PropertyKey propP = mgmt.getPropertyKey("propertyP");  // assume 'propertyP' has been created via makeProperty()
mgmt.buildIndex("byP", Vertex.class).addKey(propP).buildCompositeIndex();

and I create another Graph B and build the same index and I insert "Hello World" via

GraphA.V().addV().property("propertyP", "Hello World") and 
GraphB.V().addV().property("propertyP", "Hello World")

There should be no conflict btwn the two graphs on propertyP correct?  I assume not but something I want to be absolutely clear on.  Also, are the limits on number of vertices (2^59?) and edges (2^60) per graph or per storage installation?

thx, matt

Hi Umesh,

Can you please add the graph properties (configs) and the statements for creating the vertex labels in the graph schema (if any)?

Cheers,    Marc

Hi Matthew,

I suppose you mean identifiers instead of indices? The identifier space is per graph. The storage backends make separate files per graph.

Marc