Re: RuntimeException: while resolving method 'project'

["Hartman, Trevor" <th...@ebay.com>]

Picking this back up. With my ColumnarProjectRule enabled, I'm able to successfully run:

select count(_MAP['listingId']) as rowcount from "listings"."listings"

Side note: I noticed this triggers my ColumnarProjectRule, which extends:

RelOptRule(operand(classOf[ProjectRel],
    operand(classOf[ColumnarTableScan[S]], none())),
    "ColumnarProjectRule")

Why would an aggregate function `count` match on a ProjectRel?


Main question: why does this error when my ColumnarProjectRule is enabled?

select _MAP['listingId'], _MAP['applicationId'] from "listings"."listings"

|| Caused by: java.lang.AssertionError: Type mismatch:
|| rel rowtype:
|| RecordType((VARCHAR(1) CHARACTER SET "ISO-8859-1" COLLATE "ISO-8859-1$en_US$primary" NOT NULL, ANY NOT NULL) MAP NOT NULL _MAP) NOT NULL
|| equivRel rowtype:
|| RecordType(ANY EXPR$0, ANY EXPR$1) NOT NULL

If I disable my ColumnarProjectRule, it works. I'm not specifying any types, except for getRowType in my ColumnarTable. Should I be?

At this point I only have the single rule registered, and it doesn't do anything yet. Just trying to understand the flow/mechanics. Here's the rule source for reference (Scala):

class ColumnarProjectRule[S <: Schema]()(implicit ct: ClassTag[S])
  extends RelOptRule(operand(classOf[ProjectRel],
    operand(classOf[ColumnarTableScan[S]], none())),
    "ColumnarProjectRule")
  with StrictLogging {

  override def onMatch(call: RelOptRuleCall) {
    val project: ProjectRel = call.rel(0)
    val scan: ColumnarTableScan[S] = call.rel(1)
    val projects = project.getProjects()

    logger.info(s"onMatch $project ${project.getTraitSet} ${project.getProjects}")

    // TODO: determine fields to pass into ColumnarTableScan
    // val fields = Seq.empty[String].asJava
    val cts = new ColumnarTableScan[S](
      scan.getCluster,
      scan.getTable,
      scan.columnarTable)

    call.transformTo(cts)

  }

}

Thanks,
Trevor