gremlin | Go graph database client for TinkerPop3 Gremlin Server | Graph Database library
kandi X-RAY | gremlin Summary
kandi X-RAY | gremlin Summary
Go graph database client for TinkerPop3 Gremlin Server
Support
Quality
Security
License
Reuse
Top functions reviewed by kandi - BETA
- NewCluster initializes a cluster
- CreateConnection creates a connection to all servers .
- OptAuthEnv sets authentication information from environment variables .
- Query creates a Request object .
- SplitServers splits a connection string into a list of servers
- GraphSONSerializer serializes the request to JSON
- NewClient creates a new Client
- NewAuthInfo returns AuthInfo struct
- OptAuthUserPass is a functional option for AuthInfo .
- NewFormattedReq creates a FormattedReq
gremlin Key Features
gremlin Examples and Code Snippets
Community Discussions
Trending Discussions on gremlin
QUESTION
I'm new to using Gremlin and I need help to set the best query to select unique and filtered results.
Starting from a team
I would get player
(note: each player can play for more than one team) of each team
connected by is_friends_with
The result (I would like to get)
...ANSWER
Answered 2022-Feb-19 at 17:17Here is one way to do it using group
QUESTION
Hello dear gremlin jedi,
I have a bunch of nodes with different labels in my graph:
...ANSWER
Answered 2021-Dec-10 at 18:31You can try this approach, where in query you can map values to integer, and use simple order on those integers.
QUESTION
ANSWER
Answered 2021-Nov-16 at 18:23You should look at using the project()
step (documentation here) to get this sort of information. Without the steps to reproduce your graph, it is hard to give you the exact query, but it should look similar to the query below:
QUESTION
I was reading about Janusgraph Cache in Janusgraph documentation. I have few doubts Regarding the transaction cache. I'm using an embedded janusgrah server in my application.
- If I'm only doing a read query for eg. - g. V().has("name","ABC") using gremlin HTTP endpoint, so will this value be cached in transaction cache or database level cache? because here I'm not opening any transaction.
- If it is stored in the transaction cache, how updated values will be fetched for this vertex if I have multi-node deployment?
ANSWER
Answered 2021-Sep-12 at 08:46Regarding question 1:
If not created explicitly, transactions are created automatically. From the JanusGraph reference docs:
Every graph operation in JanusGraph occurs within the context of a transaction. According to the TinkerPop’s transactional specification, each thread opens its own transaction against the graph database with the first operation (i.e. retrieval or mutation) on the graph.
A vertex retrieved during a transaction is stored in both the transaction cache and database cache. After closing the transaction the vertex is still in the database cache (but note that since janusgraph-0.5.x the database cache is disabled by default).
Regarding question 2:
Indeed, a JanusGraph instance cannot know about modifications to vertices in the transaction caches of other instances. Only after these transactions have been closed and persisted to the storage and index backends, other instances can read modified vertices from the the backends. This also means that caches in other JanusGraph instances can be out of date, so if you want to be sure that you have the latest data from the backends, you should start a new transaction and disable the database cache (default setting).
The vertex caches are private members of JanusGraph and nowhere exposed to the user (not even in the debug logging). Cache hits in a traversal are only visible from a fast (sub-millisecond) return time.
If data consistency between transactions or janusgraph instances matters to you, you can take a look at:
- https://docs.janusgraph.org/v0.4/advanced-topics/eventual-consistency/#data-consistency
- the new CacheVertex::refresh feature in janusgraph-0.6.0 (still undocumented).
QUESTION
I have very weird issue with AWS Neptune DB. I can only change property to new value and can't use any of previous names.
I'm using gremlin and node.js.
That sounds so weird so let me to add some code:
ANSWER
Answered 2021-Sep-03 at 03:38Neptune by default uses Set cardinality. Each time you add a value you are expanding that Set as you are not explicitly using Cardinality.single
. Moreover, elementMap
will only return one element of a Set cardinality property. To see them all use valueMap
instead.
QUESTION
I'm trying to test if janusgraph could be queried with sparql. So, I found one of plug-in 'SPARQL-Gremlin' could do that. (At least, the doc said it is working.) However, when I followed the doc https://tinkerpop.apache.org/docs/current/reference/#sparql-gremlin I found that if current storage is TinkGraph, then the sparql could be run successfully. However, if I change storage solution to the remote(janusgraph), then I got error message. So, is there anyone who have been succeed based on this plugin and janusgraph?
...ANSWER
Answered 2021-Aug-26 at 13:47The comment form HadoopMarc is the likely lead to solving your problem. You need to be sure sparql-gremlin
is on your classpath for Gremlin Server when using this the way that you are in Gremlin Console. In other words, you are sending the Gremlin string of g = traversal(SparqlTraversalSource).withGraph(graph)
to be executed on the server and the server doesn't know anything about SparqlTraversalSource
if sparql-gremlin
is not in its classpath.
To get this working via Gremlin Console and :remote
(i.e. sending scripts) I would do try the following:
- Get
sparql-gremlin
on your classpath for Gremlin Server (i.e. Janus Server). You can do that best withbin/gremlin-server.sh install org.apache.tinkerpop sparql-gremlin 3.4.12
(or whatever version you are using) - Start the server with a
graph
configured for JanusGraph in the server YAML file - Connect with Gremlin Console using
:remote
as you did in your example - Test to see if Gremlin Server picked up the package by sending just submitting a script of
SparqlTraversalSource
which should return the classname. - If the previous step worked you should be able to do:
traversal(SparqlTraversalSource).withGraph(graph).sparql("SELECT ?....")
If you have that all working then a next step might be to configure a special traversal source in the Gremlin Server initialization script that is already setup with the SparqlTraversalSource
so that you can just reference it from your scripts directly.
QUESTION
I am trying to create a user vertex and a city vertex (if they do not already exist in the graph), and then add an edge between the two of them. When I execute the command in the same traversal, I run into this InternalFailureException
from Neptune.
ANSWER
Answered 2021-Aug-04 at 13:56I will investigate further why you did not get a more useful error message but I can see that the Gremlin query will need to change. After a fold
step any prior as
labels are lost as fold
reduces the traversers down to one. A fold
is both a barrier and a map. You should be able to use store
or aggregate(local)
instead of as
in this case where you have to use fold
for each coalesce
.
QUESTION
I am planning to use Janusgraph for building graph of different uses our team handles and I see that janus graph has option to use BigTable or Cassandra as storage backend. I am looking for any recommendation on which backend is more optimal/performant ( I am mainly talking about gremlin query performance on 2 hop neighbor of a node ) with JanusGraph.
I understand that performance is pretty subjective and varies based on datasize/graph connectivity and use case so best approach will be to try out myself, which I am planning to do. But has anyone else has done similar performance comparison ? Is there any general recommendation about storage backend here ?
...ANSWER
Answered 2021-Jun-10 at 18:14You're right in that performance is both:
- subjective
- depends largely on data size
I can tell you that I have done this exercise as well. To that end, I think it's important to share this comparison from DB-Engines.com.
In terms of performance, the biggest thing I'd be looking at is how each handles consistency. As a general rule, databases which enforce stronger levels of consistency typically have to sacrifice performance.
- BigTable == strong-consistent
- Cassandra == eventually consistent
Other factors worth considering, are the fact that BigTable limits you to Google Cloud (GCP). And if you don't want to lose performance over the network, you'll also need to pay for more (Janus) instances on GCP for data locality.
In terms of raw DB-Engine "score," Cassandra is currently at 114.112, while BigTable is at a paltry 3.582. These scores will change month-to-month, but in general this signifies that Cassandra has a much stronger community around it. Similarly, Cassandra has 18182 questions on this site, while BigTable only has 449. Bottom line, is that it'll be much easier to get support and answers to questions.
Just based on the underlying strength of the community, Cassandra is the better option here.
Having supported JanusGraph on Cassandra for the last few years, I can tell you that overall it's been solid. The difficulties tend to come into play with bulk data loading. But outside of that, things seem to run pretty well.
QUESTION
Gremlin queries often work with or produce lists. Sometimes it is desirable to be able to reverse a list. Currently Gremlin does not have a reverse
step so you cannot do something like:
ANSWER
Answered 2021-Apr-09 at 15:28It is possible to do this today using just existing Gremlin steps. The example below takes advantage of the index
step to give each element of a list an index number. For example:
QUESTION
Following error shows up in JanusGraph v0.5.3 server logs while retrieving edges from java client
...ANSWER
Answered 2021-Apr-08 at 23:03I believe that some of the fixes that allow the IORegistry to hook the GraphBinary serializer have not yet been released although I do see the work on the main JanusGraph branch. [1] I was having the same problem you reported but was able to get things working using the GraphSONMessageSerialializerV3d0
serializer.
[1] https://github.com/JanusGraph/janusgraph/commit/1cb4b6e849e3f9c2802722fe7f84c760cd471429
This setup code works for me:
Community Discussions, Code Snippets contain sources that include Stack Exchange Network
Vulnerabilities
No vulnerabilities reported
Install gremlin
Support
Reuse Trending Solutions
Find, review, and download reusable Libraries, Code Snippets, Cloud APIs from over 650 million Knowledge Items
Find more librariesStay Updated
Subscribe to our newsletter for trending solutions and developer bootcamps
Share this Page