I was thinking that RelFieldTrimmer can be used to transform the plan P1 to
plan P2 and then ProjectTableScanRule can be used to introduce the
BindableTableScan.
The consumer in the case of P1 is the project which only needs $0, $2, $5,
$6 so the trimmer could slim down the scan by projecting only these fields.
I didn't test if it really does this in this case because in some sense the
trimming is a bit redundant given that the project just on top has just a
subset of the columns of the table.
Note that RelFieldTrimmer could be used also during optimization (not only
in sql to rel phase) as a separate planning phase.
*P1*
LogicalProject(l_orderkey=[$0], l_suppkey=[$2], *=[*($5, -(1, $6))])
LogicalTableScan(table=[[main, lineitem]])
*P2*
LogicalProject(l_orderkey=[$0], l_suppkey=[$1], *=[*($2, -(1, $3))])
LogicalProject(l_orderkey=[$0], l_suppkey=[$2], l_extendedprice=[$5],
l_discount=[$6]])
LogicalTableScan(table=[[main, lineitem]])
On Sat, Oct 12, 2019 at 1:11 PM Wang Yanlin <1989yanlinw...@163.com> wrote:
> Just a little curious,
> RelFieldTrimmer is used to 'slimmed down' relational expression that
> projects only the columns required by its consumer.
> How can it used to do this thing?
>
>
>
>
> --
>
> Best,
> Wang Yanlin
>
>
>
> 在 2019-10-12 18:03:33，"XING JIN" <jinxing.co...@gmail.com> 写道：
> >Sure we can ~
> >If we use BindableTableScanRule to derive a BindableTableScan from
> >ProjectableFilterableTable, that would happen during a stage of
> >optimization run by RelOptPlanner. But RelFieldTrimmer works right during
> >conversion of Sql to Rel.
> >
> >Wang Yanlin <1989yanlinw...@163.com> 于2019年10月12日周六 下午5:56写道：
> >
> >> Can we just use Bindables.BINDABLE_TABLE_SCAN_RULE to translate the
> >> table scan to BindableTableScan ?
> >>
> >>
> >>
> >> --
> >>
> >> Best,
> >> Wang Yanlin
> >>
> >>
> >>
> >> At 2019-10-12 17:12:20, "XING JIN" <jinxing.co...@gmail.com> wrote:
> >> >Hi Stamatis,
> >> >In current code, BindableTableScan is only created by rules of
> >> >ProjectTableScanRule and FilterTableScanRule. I think it's better to
> keep
> >> >as it is?
> >> >I made a PR for CALCITE-3405 --
> >> https://github.com/apache/calcite/pull/1500
> >> >
> >> >The idea of the PR is quite straightforward:
> >> >1. Analyze the parent Project -- collect all the needed fields;
> >> >2. Column pruning by pushing down the needed fields to
> BindableTableScan;
> >> >3. Adjust RexInputRefs in parent Project
> >> >
> >> >@Haisheng @Stamatis It would be great if you can give a review when you
> >> >have time ~~~ Thanks a lot !
> >> >
> >> >Best,
> >> >Jin
> >> >
> >> >
> >> >Stamatis Zampetakis <zabe...@gmail.com> 于2019年10月12日周六 下午3:00写道：
> >> >
> >> >> Hi Rommel,
> >> >>
> >> >> I was hoping that this could be done at least by RelFieldTrimmer [1].
> >> Are
> >> >> you using it already?
> >> >>
> >> >> Best,
> >> >> Stamatis
> >> >>
> >> >> [1]
> >> >>
> >> >>
> >>
> https://github.com/apache/calcite/blob/master/core/src/main/java/org/apache/calcite/sql2rel/RelFieldTrimmer.java
> >> >>
> >> >> On Sat, Oct 12, 2019 at 6:06 AM XING JIN <jinxing.co...@gmail.com>
> >> wrote:
> >> >>
> >> >> > Filed a JIRA:
> >> >> > https://issues.apache.org/jira/browse/CALCITE-3405
> >> >> >
> >> >> > Haisheng Yuan <h.y...@alibaba-inc.com> 于2019年10月12日周六 上午4:34写道：
> >> >> >
> >> >> > > Yes, definitely.
> >> >> > >
> >> >> > > You can go through the project expression with InputFinder to
> find
> >> all
> >> >> > the
> >> >> > > used columns, create a logical project with those columns, and
> >> remap
> >> >> the
> >> >> > > top project with new column indexes.
> >> >> > >
> >> >> > > On the other hand, instead of creating a new intermidiate pogical
> >> >> > project,
> >> >> > > we can also update ProjectTableScanRule to accept LogicalProject
> >> that
> >> >> is
> >> >> > > not a simple mapping, and do the same task I mentioned above.
> >> >> > >
> >> >> > > - Haisheng
> >> >> > >
> >> >> > >
> ------------------------------------------------------------------
> >> >> > > 发件人：Rommel Quintanilla<rom...@blazingdb.com>
> >> >> > > 日 期：2019年10月12日 03:15:31
> >> >> > > 收件人：<dev@calcite.apache.org>
> >> >> > > 主 题：[QUESTION] Pushing up evaluations from LogicalProjects
> >> >> > >
> >> >> > > Hi, maybe you can help me.
> >> >> > > I have this portion from a larger logical plan:
> >> >> > > ..
> >> >> > > LogicalProject(l_orderkey=[$0], l_suppkey=[$2], *=[*($5,
> >> -(1,
> >> >> > > $6))])
> >> >> > > LogicalTableScan(table=[[main, lineitem]])
> >> >> > > ..
> >> >> > >
> >> >> > > Because the LogicalProject above contains an evaluation, the
> >> >> > > ProjectTableScanRule can't convert it to a BindableTableScan.
> >> >> > >
> >> >> > > I wonder if somehow the evaluation could be pushed up more or
> less
> >> like
> >> >> > > this:
> >> >> > > ..
> >> >> > > LogicalProject(l_orderkey=[$0], l_suppkey=[$1], *=[*($2, -(1,
> >> $3))])
> >> >> > > LogicalProject(l_orderkey=[$0], l_suppkey=[$2],
> >> l_extendedprice=[$5],
> >> >> > > l_discount=[$6]])
> >> >> > > LogicalTableScan(table=[[main,
> lineitem]])
> >> >> > > ..
> >> >> > >
> >> >> > > Regards.
> >> >> > >
> >> >> >
> >> >>
> >>
>
