Hi Timo,
I think this may not only affect explain() method. Method
DataStreamRel#translateToPlan is called when we need translate a FlinkRelNode
into DataStream or DataSet, we add desired operators in execution environment.
By side effect, I mean that if we call DataStreamRel#translateToPlan on same
RelNode several times, the same operators are added in execution environment
more than once, but actually we need that for only one time. Correct me if I
misunderstood that.
I will open an issue late this day, if this is indeed a problem.
Best,
wangsan
> On Aug 21, 2018, at 10:16 PM, Timo Walther <twal...@apache.org> wrote:
>
> Hi,
>
> this sounds like a bug to me. Maybe the explain() method is not implemented
> correctly. Can you open an issue for it in Jira?
>
> Thanks,
> Timo
>
>
> Am 21.08.18 um 15:04 schrieb wangsan:
>> Hi all,
>>
>> I noticed that the DataStreamRel#translateToPlan is non-idempotent, and that
>> may cause the execution plan not as what we expected. Every time we call
>> DataStreamRel#translateToPlan (in TableEnvirnment#explain,
>> TableEnvirnment#writeToSink, etc), we add same operators in execution
>> environment repeatedly.
>>
>> Should we eliminate the side effect of DataStreamRel#translateToPlan ?
>>
>> Best, Wangsan
>>
>> appendix
>>
>> tenv.registerTableSource("test_source", sourceTable)
>>
>> val t = tenv.sqlQuery("SELECT * from test_source")
>> println(tenv.explain(t))
>> println(tenv.explain(t))
>>
>> implicit val typeInfo = TypeInformation.of(classOf[Row])
>> tenv.toAppendStream(t)
>> println(tenv.explain(t))
>> We call explain three times, and the Physical Execution Plan are all
>> diffrent.
>>
>> == Abstract Syntax Tree ==
>> LogicalProject(f1=[$0], f2=[$1])
>> LogicalTableScan(table=[[test_source]])
>>
>> == Optimized Logical Plan ==
>> StreamTableSourceScan(table=[[test_source]], fields=[f1, f2],
>> source=[CsvTableSource(read fields: f1, f2)])
>>
>> == Physical Execution Plan ==
>> Stage 1 : Data Source
>> content : collect elements with CollectionInputFormat
>>
>> Stage 2 : Operator
>> content : CsvTableSource(read fields: f1, f2)
>> ship_strategy : FORWARD
>>
>> Stage 3 : Operator
>> content : Map
>> ship_strategy : FORWARD
>>
>>
>> == Abstract Syntax Tree ==
>> LogicalProject(f1=[$0], f2=[$1])
>> LogicalTableScan(table=[[test_source]])
>>
>> == Optimized Logical Plan ==
>> StreamTableSourceScan(table=[[test_source]], fields=[f1, f2],
>> source=[CsvTableSource(read fields: f1, f2)])
>>
>> == Physical Execution Plan ==
>> Stage 1 : Data Source
>> content : collect elements with CollectionInputFormat
>>
>> Stage 2 : Operator
>> content : CsvTableSource(read fields: f1, f2)
>> ship_strategy : FORWARD
>>
>> Stage 3 : Operator
>> content : Map
>> ship_strategy : FORWARD
>>
>> Stage 4 : Data Source
>> content : collect elements with CollectionInputFormat
>>
>> Stage 5 : Operator
>> content : CsvTableSource(read fields: f1, f2)
>> ship_strategy : FORWARD
>>
>> Stage 6 : Operator
>> content : Map
>> ship_strategy : FORWARD
>>
>>
>> == Abstract Syntax Tree ==
>> LogicalProject(f1=[$0], f2=[$1])
>> LogicalTableScan(table=[[test_source]])
>>
>> == Optimized Logical Plan ==
>> StreamTableSourceScan(table=[[test_source]], fields=[f1, f2],
>> source=[CsvTableSource(read fields: f1, f2)])
>>
>> == Physical Execution Plan ==
>> Stage 1 : Data Source
>> content : collect elements with CollectionInputFormat
>>
>> Stage 2 : Operator
>> content : CsvTableSource(read fields: f1, f2)
>> ship_strategy : FORWARD
>>
>> Stage 3 : Operator
>> content : Map
>> ship_strategy : FORWARD
>>
>> Stage 4 : Data Source
>> content : collect elements with CollectionInputFormat
>>
>> Stage 5 : Operator
>> content : CsvTableSource(read fields: f1, f2)
>> ship_strategy : FORWARD
>>
>> Stage 6 : Operator
>> content : Map
>> ship_strategy : FORWARD
>>
>> Stage 7 : Data Source
>> content : collect elements with CollectionInputFormat
>>
>> Stage 8 : Operator
>> content : CsvTableSource(read fields: f1, f2)
>> ship_strategy : FORWARD
>>
>> Stage 9 : Operator
>> content : Map
>> ship_strategy : FORWARD
>>
>> Stage 10 : Operator
>> content : to: Row
>> ship_strategy : FORWARD
>>
>> Stage 11 : Data Source
>> content : collect elements with CollectionInputFormat
>>
>> Stage 12 : Operator
>> content : CsvTableSource(read fields: f1, f2)
>> ship_strategy : FORWARD
>>
>> Stage 13 : Operator
>> content : Map
>> ship_strategy : FORWARD
>>
>>
