Re: How to convert a logical operator into multiple physical operators

[Bhavya Aggarwal <bh...@knoldus.com>]

Thanks for the reply, so I looked at the example and created a Nested
RelNode for my TableScanOperator as shown below

override def onMatch(call: RelOptRuleCall): Unit = {
    val tableScan : LogicalTableScan = call.rel[LogicalTableScan](0);
    val builder = call.builder()
    val newOp = new ReadTable(
      tableScan.getCluster,
      RelTraitSet.createEmpty
        .plus(SqreamRel.CONVENTION),
      List.empty,
      tableScan.getTable
    )

    val input = builder.push(tableScan).empty().build()

    val cpuDecompress  = new CpuDecompress(tableScan.getCluster,
 RelTraitSet.createEmpty
      .plus(SqreamRel.CONVENTION), newOp)


    val collationListBuilder = new ImmutableList.Builder[RelFieldCollation]

    val cpuToGpu = new CpuToGpu(tableScan.getCluster,
      RelTraitSet.createEmpty().plus(SqreamRel.CONVENTION),
      cpuDecompress,RelCollationImpl.of(collationListBuilder.build()))

    val gpuTransform = new
GpuTransform(tableScan.getCluster,RelTraitSet.createEmpty().plus(SqreamRel.CONVENTION),
cpuToGpu )

    builder.push(gpuTransform)
    call.transformTo( builder.build())

  }

But in this case, I am getting an exception from the Planner which is
related to ReadTable which is extending the tablescan. How can I wrap my
operators around the table scan operator.

Exception in thread "main" java.lang.ClassCastException: class
com.sqream.calcite.aux.rel.ReadTable cannot be cast to class
org.apache.calcite.plan.hep.HepRelVertex
(com.sqream.calcite.aux.rel.ReadTable and
org.apache.calcite.plan.hep.HepRelVertex are in unnamed module of loader
'app')
at org.apache.calcite.plan.hep.HepPlanner.addRelToGraph(HepPlanner.java:849)
at org.apache.calcite.plan.hep.HepPlanner.addRelToGraph(HepPlanner.java:819)
at org.apache.calcite.plan.hep.HepPlanner.addRelToGraph(HepPlanner.java:819)
at
org.apache.calcite.plan.hep.HepPlanner.applyTransformationResults(HepPlanner.java:754)
at org.apache.calcite.plan.hep.HepPlanner.applyRule(HepPlanner.java:565)
at org.apache.calcite.plan.hep.HepPlanner.applyRules(HepPlanner.java:427)
at
org.apache.calcite.plan.hep.HepPlanner.executeInstruction(HepPlanner.java:264)
at
org.apache.calcite.plan.hep.HepInstruction$RuleInstance.execute(HepInstruction.java:127)
at
org.apache.calcite.plan.hep.HepPlanner.executeProgram(HepPlanner.java:223)
at org.apache.calcite.plan.hep.HepPlanner.findBestExp(HepPlanner.java:210)
at TestSqream$.delayedEndpoint$TestSqream$1(TestSqream.scala:77)
at TestSqream$delayedInit$body.apply(TestSqream.scala:24)
at scala.Function0.apply$mcV$sp(Function0.scala:39)
at scala.Function0.apply$mcV$sp$(Function0.scala:39)
at scala.runtime.AbstractFunction0.apply$mcV$sp(AbstractFunction0.scala:17)
at scala.App.$anonfun$main$1$adapted(App.scala:80)
at scala.collection.immutable.List.foreach(List.scala:431)
at scala.App.main(App.scala:80)
at scala.App.main$(App.scala:78)
at TestSqream$.main(TestSqream.scala:24)
at TestSqream.main(TestSqream.scala)


>
>
> On Thu, Nov 26, 2020 at 1:20 PM Bhavya Aggarwal <bh...@knoldus.com>
> wrote:
>
>> Hi All,
>>
>> We are trying to use Apache Calcite as and CBO for our homegrown DB and
>> there one Logical operator will translate into multiple Physical Operations
>> at our database e.g. a simple TableScan will convert into the given
>> structure. In the example above we have to decompress the data, then
>> rechunk it. However, I am able to create 1:1 conversion. Please let me know
>> how to proceed. Any help will be much appreciated.
>>
>> select id from users where id = 5;
>> AddToNetworkQueue 1
>>   Rechunk 2
>>     ReorderInput 3
>>         ReorderInput 4
>>               Filter 5
>>                  Rechunk 6
>>                       Decompress 7
>>                            ReadTable 8
>>
>> Thanks and regards
>> Bhavya
>> --
>> *Bhavya Aggarwal*
>> CTO & Partner
>> Knoldus Inc. <http://www.knoldus.com/>
>> +91-9910483067
>> Canada - USA - India - Singapore
>> <https://in.linkedin.com/company/knoldus> <https://twitter.com/Knolspeak>
>> <https://www.facebook.com/KnoldusSoftware/> <https://blog.knoldus.com/>
>>
>
>
>

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