David Cai created CARBONDATA-3752:
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Summary: Query on carbon table should support reusing Exchange
Key: CARBONDATA-3752
URL: https://issues.apache.org/jira/browse/CARBONDATA-3752
Project: CarbonData
Issue Type: Improvement
Reporter: David Cai
Query on carbon table should support reusing Exchange
[Reproduce]
create table t1(c1 int, c2 string) using carbondata
insert into t1 values(1, 'abc')
explain
select c2, sum(c1) from t1 group by c2
union all
select c2, sum(c1) from t1 group by c2
[Physical Plan]
{noformat}
Union
:- *(2) HashAggregate(keys=[c2#37], functions=[sum(cast(c1#36 as bigint))])
: +- Exchange hashpartitioning(c2#37, 200)
: +- *(1) HashAggregate(keys=[c2#37], functions=[partial_sum(cast(c1#36 as
bigint))])
: +- *(1) FileScan carbondata default.t1[c1#36,c2#37] ReadSchema:
struct<c1:int,c2:string>
+- *(4) HashAggregate(keys=[c2#37], functions=[sum(cast(c1#36 as bigint))])
+- Exchange hashpartitioning(c2#37, 200)
+- *(3) HashAggregate(keys=[c2#37], functions=[partial_sum(cast(c1#36 as
bigint))])
+- *(3) FileScan carbondata default.t1[c1#36,c2#37] ReadSchema:
struct<c1:int,c2:string>{noformat}
It should reuse Exchange like Following:
{noformat}
Union
:- *(2) HashAggregate(keys=[c2#37], functions=[sum(cast(c1#36 as bigint))])
: +- Exchange hashpartitioning(c2#37, 200)
: +- *(1) HashAggregate(keys=[c2#37], functions=[partial_sum(cast(c1#36 as
bigint))])
: +- *(1) FileScan carbondata default.t1[c1#36,c2#37] ReadSchema:
struct<c1:int,c2:string>
+- *(4) HashAggregate(keys=[c2#37], functions=[sum(cast(c1#36 as bigint))])
+- ReusedExchange [c2#37, sum#54L], Exchange hashpartitioning(c2#37,
200){noformat}
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