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From weijie tong <tongweijie...@gmail.com>
Subject Re: Is it possible to delegate data joins and filtering to the datasource ?
Date Thu, 30 Mar 2017 00:46:05 GMT
I mean the rule you write could be placed in the PlannerPhase.JOIN_PlANNING
which uses the HepPlanner. This phase is to solve the logical relnode .
Hope to help you.
Muhammad Gelbana <m.gelbana@gmail.com>于2017年3月30日 周四上午12:07写道:

> ​Thanks a lot Weijie, I believe I'm very close now. I hope you don't mind
> few more questions please:
>
>
>    1. The new rule you are mentioning is a physical rule ? So I should
>    implement the Prel interface ?
>    2. By "traversing the join to find the ScanRel"
>       - This sounds like I have to "search" for something. Shouldn't I just
>       work on transforming the left (i.e. DrillJoinRel's getLeft() method)
> and
>       right (i.e. DrillJoinRel's getLeft() method) join objects ?
>       - The "left" and "right" elements of the DrillJoinRel object are of
>       type RelSubset, not *ScanRel* and I can't find a type called
> *ScanRel*.
>       I suppose you meant *ScanPrel*, specially because it implements the
>       *Prel* interface that provides the *getPhysicalOperator* method.
>    3. What if multiple physical or logical rules match for a single node,
>    what decides which rule will be applied and which will be rejected ? Is
> it
>    the *AbstractRelNode.computeSelfCost(RelOptPlanner)* method ? What if
>    more than one rule produces the same cost ?
>
> I'll go ahead and see what I can do for now before hopefully you may offer
> more guidance. THANKS A LOT.
>
> *---------------------*
> *Muhammad Gelbana*
> http://www.linkedin.com/in/mgelbana
>
> On Wed, Mar 29, 2017 at 4:23 AM, weijie tong <tongweijie178@gmail.com>
> wrote:
>
> > to avoid misunderstanding , the new equivalent ScanRel is to have the
> > joined ScanRel nodes's GroupScans, as the GroupScans indirectly hold the
> > underlying storage information.
> >
> > On Wed, Mar 29, 2017 at 10:15 AM, weijie tong <tongweijie178@gmail.com>
> > wrote:
> >
> > >
> > > my suggestion is you define a rule which matches the DrillJoinRel
> RelNode
> > > , then at the onMatch method ,you traverse the join children to find
> the
> > > ScanRel nodes . You define a new ScanRel which include the ScanRel
> nodes
> > > you find last step. Then transform the JoinRel to this equivalent new
> > > ScanRel.
> > > Finally , the plan tree will not have the JoinRel but the ScanRel.
>  You
> > > can let your join plan rule  in the PlannerPhase.JOIN_PLANNING.
> > >
> >
>

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