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rpuga

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•Created by rpuga on 1/6/2025 in #questions

Graph does not support the provided graph computer: SparkGraphComputer

Hi, I'm trying to instantiate a janusgraph server that correctly exports a graph.traversal().withComputer(SparkGraphComputer) As I was unable to find specific documentation on this, I have tried following this: https://stackoverflow.com/questions/45323666/unable-to-use-sparkgraphcomputer-with-tinkerpop-3-2-3-and-janusgraph-0-1-1-in-re However, I'm unable to instantiate a graph of this type: hadoopgraph[cassandrainputformat->gryooutputformat]. When I attempt to use graph: conf/hadoop-graph/read-cql.properties in the server configuration .yaml file, I get the following server error: Need to set configuration value: root.storage.backend If I set the storage backend by adding storage.backend=cql and storage.cql.keyspace=janusgraph I'm able to start the janusgraph server, but when I attempt to use the og traversal source, I get the following error: Graph does not support the provided graph computer: SparkGraphComputer Does anyone have any suggestions on how to properly setup a janusgraph server so that queries are executed using SparkGraphComputer? BTW: I'm able to correctly run queries from the gremlin console, by following the example in the official janusgraph documentation: https://docs.janusgraph.org/advanced-topics/hadoop/ But what I'm interested in is instantiating a janusgraph server that by defualt runs all queries on a given traveral source using SparkGraphComputer.

7 replies

JJanusGraph

•Created by rpuga on 12/18/2024 in #questions

Running OLAP queries on Janusgraph outside the Gremlin Console (from Java and G.V())

Hi, I'm able to run OLAP queries against my graph DB from the Gremlin Console, by following the directions provided here: https://docs.janusgraph.org/advanced-topics/hadoop/ However, I would like to also run OLAP queries without using the console, from an embedded Janusgraph Java application as well as from G.V(). In G.V(), I tried this while selecting Groovy Mode for query submission:

graph = GraphFactory.open('/opt/janusgraph/conf/hadoop-graph/spark-cql.properties')
g = graph.traversal().withComputer(SparkGraphComputer)
g.V().groupCount().by(label()).toList()

graph = GraphFactory.open('/opt/janusgraph/conf/hadoop-graph/spark-cql.properties')
g = graph.traversal().withComputer(SparkGraphComputer)
g.V().groupCount().by(label()).toList()

but I get the following error:

No such property: SparkGraphComputer for class: Script10

No such property: SparkGraphComputer for class: Script10

I'm assuming this is because the needed plugins are not loaded. I tried:

:plugin use tinkerpop.hadoop
:plugin use tinkerpop.spark

:plugin use tinkerpop.hadoop
:plugin use tinkerpop.spark

but this does not work outside of the console. Any suggestions, @gdotv ? Also, is there any example code I could use to run OLAP queries from a Java application? Thanks!

8 replies

JJanusGraph

•Created by rpuga on 11/26/2024 in #questions

Mapping.STRING not working as expected?

Hi everyone! Based on the Janusgraph text search documentation:

When a string mapping is configured, the string value is indexed and can be queried "as-is" - including stop words and non-letter characters

When a string mapping is configured, the string value is indexed and can be queried "as-is" - including stop words and non-letter characters

However, this does not seem to work as expected. Example: I have an index that looks like this:

ipstr = mgmt.makePropertyKey('ip_str').dataType(String.class).make()
mgmt.buildIndex('ipstrVMixedIndex', Vertex.class).addKey(ipstr, Mapping.STRING.asParameter()).buildMixedIndex("search")

ipstr = mgmt.makePropertyKey('ip_str').dataType(String.class).make()
mgmt.buildIndex('ipstrVMixedIndex', Vertex.class).addKey(ipstr, Mapping.STRING.asParameter()).buildMixedIndex("search")

and nodes of type ipaddr that have ip_str propery values like 192.168.1.0/24 as well as 10.24.2.3 (no CIDR). Now when I run a query like:

g.V().has("ipaddr", "ip_str", textContains("/24"))

g.V().has("ipaddr", "ip_str", textContains("/24"))

it returns both IPs that end in /24 as well as IPs that happen to contain 24 in them, like the two examples above. This does not seem to match the expected behavior based on my understanding of the Mapping.STRING documentation. Am I missing something? Thanks! PS: the indexing backend is ES, in case it is important

2 replies

JJanusGraph

•Created by rpuga on 5/27/2024 in #questions

Unable to load GraphSON file

Hi, I'm trying to load a very simple .json graph into JanusGraph from the gremlin console, but I get this error:

gremlin> g.io("/opt/janusgraph/graphson-test1.json").read().iterate();
Label can not be null

gremlin> g.io("/opt/janusgraph/graphson-test1.json").read().iterate();
Label can not be null

although the label is indeed present:

{"vertices":[{"id":"id_test","label":"person","name":"Jack"}],"edges":[]}

{"vertices":[{"id":"id_test","label":"person","name":"Jack"}],"edges":[]}

any idas why? Additional info: I'm using JanusGraph 1.0.0 that is setup to accept custom vertext IDs. All works well, but I'm unable to do bulk loads from .json. Thanks!

8 replies

JJanusGraph

•Created by rpuga on 5/26/2024 in #questions

Gremlin statement exceeds the maximum compilation size

Hi all, I'm trying to do some script-based bulk writes to a JanusGraph server, but I get the following error message

'status': {'message': 'The Gremlin statement that was submitted exceeds the maximum compilation size allowed by the JVM, please split it into multiple smaller statements ...}

'status': {'message': 'The Gremlin statement that was submitted exceeds the maximum compilation size allowed by the JVM, please split it into multiple smaller statements ...}

I have set maxContentLength: 524288 in the server .yaml file to allow my client to sbmit larger scripts, because I found a significant performance improvement when submitting a larger set of queries at once. But now I'm hitting the JVM limit for compilation size, which I'd like to increase, if possible. Is there a way to increase the JVM limit? Thanks!

5 replies

JJanusGraph

•Created by rpuga on 4/21/2024 in #questions

~20% write performance hit when using custom str IDs?

Hi, I've been experimenting with using custom vertex IDs. I have a process that reads data from a file and writes (or updates with mergeV()) nodes to a JanusGraph 1.0.0 instance with a Cassandra+ES backend. Keeping exactly the same client code and test data, I noticed a 20% write slowdown when writing nodes with custom string IDs, rather than custom int IDs. In both cases, the IDs are exactly the same, with the only difference being that in one case I convert int to string, before submitting the query to the JG server (I'm using parametrized scripts submitted via gremlin-python). Is this a known issue? (I could not find info about this in the documentation)

13 replies

ATApache TinkerPop

•Created by rpuga on 3/23/2024 in #questions

mergeE(): increment counter on match

Hi, is there an easy way to increment an existing edge property based on its current value using mergeE() in one single query? (e.g., counter += 1) Something similar to this:

g.mergeE([(T.label):'called', (from): person1, (to):person2]).
  option(Merge.onCreate,['num_calls': 1]).
  option(Merge.onMatch,['num_calls': X+1])

g.mergeE([(T.label):'called', (from): person1, (to):person2]).
  option(Merge.onCreate,['num_calls': 1]).
  option(Merge.onMatch,['num_calls': X+1])

where X is the current value of edge propery num_calls.

16 replies

JJanusGraph

•Created by rpuga on 1/21/2024 in #questions

Changing default ES index name prefix

Hi, is it possible to change the default prefix of Elasticsearch index names? Currently, when I define a mixed index, JanusGraph creates a correspoing index in ES named janusgraph_<index_name>. I would like to change the prefix for all indices to something like jgtest1_<index_name>. I tried following the documentation (https://docs.janusgraph.org/index-backend/elasticsearch/#janusgraph-indexx-and-indexxelasticsearch-options), adding this line to the JanusGraph server .properties file: index.search.elasticsearch.index-name = jgtest1 however, this does not seem to work. I know that this is a GLOBAL_OFFLINE option, so I stopped the server, changed the Cassandra keyspace name to create a new DB, and then restarted the server. After defining the schema and mixed indices the ES index names are still the same as before. Namely the prefix of the indices that are create is still janusgraph_, instead of jgtest1_. Isn't the index-name option supposed to work? Am I missing somthing? Thanks!

10 replies

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