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From Dmitry Vasilenko <dvasi...@gmail.com>
Subject Re: Does Atlas really support Gremlin queries?
Date Mon, 18 Jan 2016 13:59:48 GMT
Hi Hemanth,

The Atlas DSL API does not support ORDER BY and LIMIT as of yet. It returns
the complete result set and does not scale well if you have a lot of data.

See also
https://issues.apache.org/jira/browse/ATLAS-435
https://issues.apache.org/jira/browse/ATLAS-436

Pagination
https://issues.apache.org/jira/browse/ATLAS-347
is definitely nice to have but it forces the client to filter out the
results instead of pushing the processing to the server.

If the DSL is extended to support ORDER BY and LIMIT it will be the
preferable way to search the repository but until that functionality is
implemented using Gremlin queries seems to be the only option.

Regards
Dmitry







On Sun, Jan 17, 2016 at 10:38 PM, Hemanth Yamijala <
hyamijala@hortonworks.com> wrote:

> Dmitry,
>
> Apologies upfront for a possibly not very helpful response. This is more
> to understand from a product perspective.
>
> Could you tell us what your motivation is to go directly with Gremlin as
> opposed to either going through the UI or the DSL API? Are there things
> that you would like to see in either that are not currently supported? For
> example, I know that the current REST APIs do not restrict number of
> results and had opened https://issues.apache.org/jira/browse/ATLAS-347
> for this. Are there enhancements like this that would help using Atlas
> easier?
>
> Or do you prefer the Gremlin queries for some other reason?
>
> Thanks
> hemanth
>
>
>
>
> On 1/13/16, 10:40 PM, "Dmitry Vasilenko" <dvasilen@gmail.com> wrote:
>
> >Dear developers:
> >
> >I am trying to create a query that includes order by and limit the result
> >to a single instance and as Atlas DSL
> >does not  support ORDER BY and LIMIT I am trying to use Gremlin.
> >
> >The simple Gremlin query like
> >
> >g.V().has("__guid", "9b1329e0-12ff-4d45-ad51-9455e18736b9" ).toList()
> >
> >works just fine but anything a bit more complex that includes
> >order().by(...).limit(1) fails miserably with QueryParsingException.
> >
> >I would naively think that the Gremlin syntax like this should be
> >well-formed and perfectly valid:
> >
> >g.V().has("__guid", "9b1329e0-12ff-4d45-ad51-9455e18736b9"
> >).order().by("name").limit(1).toList()
> >
> >but unfortunately it does not work (QueryParsingException)
> >
> >Does any one know how the Gremlin query with order().by() .... limit(1)
> >should look like to be palatable by Atlas?
> >
> >
> >Regards
> >Dmitry Vasilenko
>

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