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From Wes McKinney <wesmck...@gmail.com>
Subject Re: How to understand this comment
Date Wed, 03 Apr 2019 04:39:24 GMT
On Tue, Apr 2, 2019 at 10:08 PM ming zhang <ming.zhang.china@gmail.com> wrote:
>
> in a case where there are multiple ways to retrieve this logical data set,
> how to represent this in the response?
>
> for example, assume there is a data set that has
> part 1 in endpoint 1 and part 2 in endpoint 2 with tcp as transport
> both part 1 and part 2 in endpoint 3, with infiniband as transport
>
> now how we return this back to client so client decide which one to consume?
>

One way to do this would be to have the Ticket payload contain a
serialized object (e.g. a protocol buffer) which contains this
additional metadata for the client to decide which endpoints to
access.

The Ticket returned in FlightEndpoint is opaque data so can contain
anything. In our performance test server the Ticket is a protobuf:

https://github.com/apache/arrow/blob/master/cpp/src/arrow/flight/perf-server.cc#L169

> the mental model i have with FightService is similar to travel with flight.
>
> - a travel agency lists many travel choices.
> - for a trip from NYC to SFO, there are different itinerary, like NYC->SFO
> directly. NYC->Chicago -> SFO, and so on.
> - for each itinerary, there could be one or more logical parts (hop)
> - for each hop, there are different ways, like business class, economic
> class, etc
> - they all need a ticket to finish the trip.
>
> is this right, or way off?
>
> Thanks
> Ming
>
>
> On Tue, Apr 2, 2019 at 9:59 PM Wes McKinney <wesmckinn@gmail.com> wrote:
>
> > Hi,
> >
> > A FlightGetInfo plan corresponds to a single logical dataset. The
> > dataset may be spread across multiple endpoints, so if you want the
> > whole dataset you have to execute DoGet against them all.
> >
> > I'm not sure what you mean by "provide more than one execution plan".
> >
> > - Wes
> >
> > On Tue, Apr 2, 2019 at 7:54 PM ming zhang <ming.zhang.china@gmail.com>
> > wrote:
> > >
> > > Hi All
> > >
> > > Wonder how to understand this comment?
> > >
> > > Looks like this assume we only have one "itinerary" and finish it need to
> > > consume all the flight endpoints.
> > >
> > >   /*
> > >    * A list of endpoints associated with the flight. To consume the whole
> > >    * flight, all endpoints must be consumed.
> > >    */
> > >
> > > What if we do want to provide more than one execution plan (itinerary)
> > and
> > > each have multiple steps?
> > >
> > > Thanks
> > > Ming
> >

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