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From Seetharam Venkatesh <venkat...@innerzeal.com>
Subject Re: Does Atlas really support Gremlin queries?
Date Tue, 19 Jan 2016 20:27:28 GMT
I added Gremlin and Rexster APIs as an experiment and mostly for testing
instead of pointing Titan to the DB instance outside. I should have
annotated them as LimitedPrivate to avoid confusion.

If you notice, Gremlin is a pass-through today and we did not intend to
support it in the long run. Atlas DSL is rich and type-aware. We should
enhance the DSL and provide the features that you are asking for.

Rexster is also a read-only API that I thought was removed.

Thanks!

Venkatesh

On Mon, Jan 18, 2016 at 6:00 AM Dmitry Vasilenko <dvasilen@gmail.com> wrote:

> 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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