Just want to revive this old topic since I need to know about this
mysterious method for my current work. I would appreciate if you guys could
share your expertise/knowledge about it.
On Mon, Sep 4, 2017 at 8:43 AM, abdullah alamoudi <bamou...@gmail.com>
> It seems that it is set to true when the operator has the two properties:
> 1. A mapping from no more than one input tuple to one or more output
> tuples can be established.
> 2. Is not blocking operator.
> As per this, we can clearly see that:
> - IndexInsertDeleteUpsertOperator should have isMap() set as true
> - TokenizeOperator should have isMap() set as true
> Did I get anything wrong here?
> > On Sep 3, 2017, at 11:35 AM, Taewoo Kim <wangs...@gmail.com> wrote:
> > My understanding is that isMap() is set to true when the cardinality of
> > input may not be equal to the the cardinality of the output. To settle
> > issue, I come up with one explicit property in my Limit Push down branch.
> > The attribute is called canDecreaseCardinality.
> > On Sun, Sep 3, 2017 at 19:46 abdullah alamoudi <bamou...@gmail.com>
> >> Dear devs,
> >> I was going over implementations of ILogicalOperator.isMap in our code
> >> base and here is the breakdown:
> >> isMap()
> >> true:
> >> -Assign
> >> -AbstractReplicateOperator
> >> -AbstractUnnestOperator
> >> -ExchangeOperator
> >> -InsertDeleteUpsertOperator
> >> -LimitOperator
> >> -ProjectOperator
> >> -SelectOperator
> >> false:
> >> -Order
> >> -Aggregate
> >> -RunningAggregate
> >> -AbstractBinaryJoin
> >> -AbstractOperatorWithNestedPlans
> >> -DataSourceScanOperator
> >> -DistinctOperator
> >> -DistributeResultOperator
> >> -EmptyTupleSourceOperator
> >> -IndexInsertDeleteUpsertOperator
> >> -IntersectOperator
> >> -MaterializeOperator
> >> -NestedTupleSourceOperator
> >> -ScriptOperator
> >> -SinkOperator
> >> -TokenizeOperator
> >> -UnionAllOperator
> >> -WriteOperator
> >> -WriteResultOperator
> >> As I understood at some point is that isMap means (does this operator
> >> input tuples to output tuples without blocking?). I am not sure how
> >> accurate this description is but it clearly introduces a problem as:
> >> * InsertDeleteUpsertOperator.isMap() -> true
> >> * IndexInsertDeleteUpsertOperator.isMap() -> false
> >> Moreover,
> >> TokenizeOperator.isMap() -> false
> >> AbstractUnnestOperator.isMap() -> true
> >> while clearly, as per the definition above, these two operators should
> >> have the same output: true
> >> Can someone solve the mystery?
> >> Once this is solved, I will add a wiki entry to explain this flag.
> >> Cheers,
> >> Abdullah.