[jira] [Commented] (TINKERPOP-2604) TinkerGraph could not order vertex/edge without specified property.

["Stephen Mallette (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TINKERPOP-2604?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17403155#comment-17403155 ] 

Stephen Mallette commented on TINKERPOP-2604:
---------------------------------------------

Interesting - i'm a little surprised that it doesn't work as you say. i would have thought that we would have had some natural ordering on the element ID. i think we could implement those semantics, but will need to bring it up in the community for discussion. thanks.

> TinkerGraph could not order vertex/edge without specified property.
> -------------------------------------------------------------------
>
>                 Key: TINKERPOP-2604
>                 URL: https://issues.apache.org/jira/browse/TINKERPOP-2604
>             Project: TinkerPop
>          Issue Type: Bug
>          Components: tinkergraph
>    Affects Versions: 3.4.10
>         Environment: Version: 3.4.10
> OS : CentOS8
> Storage Backend: in-memory
>            Reporter: Zheng Qin
>            Priority: Major
>
> h2. TinkerGraph could not order vertex/edge without specified property
> h3. Environment
> bq. Version: 3.4.10
> bq.OS : CentOS8
> bq.Storage Backend: in-memory
> h3. Bug description
> We expect to get the vertexes/edges ordered by their ID using gremlin *order* query without specified property like `"g.V()/E().order().by(asc/desc)"` in TinkerGraph, as we can get the result by the same query in JanusGraph.
> h3. Current behavior
> An exception was thrown:
> {code:java}
> java.util.concurrent.ExecutionException: org.apache.tinkerpop.gremlin.driver.exception.ResponseException: org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerVertex cannot be cast to java.lang.Comparable
> 	at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357)
> 	at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1908)
> 	at org.gdbtesting.validation.ValidateTinkerOrderAsc.main(ValidateTinkerOrderAsc.java:27)
> Caused by: org.apache.tinkerpop.gremlin.driver.exception.ResponseException: org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerVertex cannot be cast to java.lang.Comparable
> {code}
> h3. Reproduce
> {code:java}
> GraphTraversalSource g = connection.getG();
> g.E().drop().iterate();
> g.V().drop().iterate();
> try {
>     Vertex v1 = g.addV().property("price",3).next();
>     Vertex v2 = g.addV().property("price",4).next();
>     Vertex v3 = g.addV().property("price",5).next();
>     Vertex v4 = g.addV().property("price",6).next();
>     String query = "g.V().order().by(asc)";
>     System.out.println("query: " + query);
>     try{
>          List<Result> results;
>          results = connection.getClient().submit(query).all().get();
>          for (Result r : results) {
>              System.out.println(r);
>           }
>         }catch(Exception e){
>              e.printStackTrace();
>         }
>      } catch (Exception e) {
>           e.printStackTrace();
> } finally {
>      System.exit(0);
> }
> {code}
> We could successfully run the *order()* step with specified property in TinkerGraph, like using "g.V().id().order().by(asc)" to get vertexes ordered by vertex ID. We bring up the issue for we are wondering whether query without specified property, like "g.V()/E().order().by(asc/desc)", is grammatically correct or not, as we find it could be accepted in JanusGraph while get exception above in TinkerGraph.



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