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
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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.
