Push down common aggregation filters #18774
Description
Is your feature request related to a problem or challenge?
When a SQL query contains multiple aggregations with filters, those filters are currently not pushed down. For instance in a query like
select
sum(a) filter (where a > 1 and a % 2 = 0),
count(a) filter (where a > 1)
from t;
a > 1 is common for both aggregates so the query could be rewritten as
select
sum(a) filter (where a % 2 = 0),
count(a)
from t
where a > 1;
Describe the solution you'd like
When all aggregations of an aggregate node share partial or complete filter expressions, extract the common parts to a filter node. Rather than executing the above query as
AggregateExec: mode=Single, gby=[], aggr=[sum(t.a) FILTER (WHERE t.a > Int64(1) AND t.a % Int64(2) = Int64(0)), count(t.a) FILTER (WHERE t.a > Int64(1))]
ProjectionExec: expr=[column1@0 > 1 as __common_expr_1, column1@0 as a]
DataSourceExec: partitions=1, partition_sizes=[1]
it could be executed as
AggregateExec: mode=Single, gby=[], aggr=[sum(t.a) FILTER (WHERE t.a % Int64(2) = Int64(0)), count(t.a)]
ProjectionExec: expr=[column1@0 as a]
CoalesceBatchesExec: target_batch_size=8192
FilterExec: column1@0 > 1
DataSourceExec: partitions=1, partition_sizes=[1]
Describe alternatives you've considered
No response
Additional context
No response