Filter Operator appear twice?

[Yingyi Bu]

Hi,

Consider the following query:

INSERT OVERWRITE TABLE q1_pricing_summary_report
SELECT
L_RETURNFLAG, L_LINESTATUS, SUM(L_QUANTITY), SUM(L_EXTENDEDPRICE),
SUM(L_EXTENDEDPRICE*(1-L_DISCOUNT)),
SUM(L_EXTENDEDPRICE*(1-L_DISCOUNT)*(1+L_TAX)), AVG(L_QUANTITY),
AVG(L_EXTENDEDPRICE), AVG(L_DISCOUNT), COUNT(1)
FROM
  lineitem
WHERE
  L_SHIPDATE<='1998-09-02'
  GROUP BY L_RETURNFLAG, L_LINESTATUS
  ORDER BY L_RETURNFLAG, L_LIN

There is a segment in the query plan like this：
Filter Operator
       predicate:
             expr: (l_shipdate <= '1998-09-02')
             type: boolean
                      Filter Operator
                                predicate:
                                   expr: (l_shipdate <= '1998-09-02')
                                    type: boolean


Why the filter operator repeatedly appear twice?


Similarly, for query
insert overwrite table q2_minimum_cost_supplier_tmp1
select
  s.s_acctbal, s.s_name, n.n_name, p.p_partkey, ps.ps_supplycost,
p.p_mfgr, s.s_address, s.s_phone, s.s_comment
from
  nation n join region r
  on
    n.n_regionkey = r.r_regionkey and r.r_name = 'EUROPE'
  join supplier s
  on
s.s_nationkey = n.n_nationkey
  join partsupp ps
  on
s.s_suppkey = ps.ps_suppkey
  join part p
  on
    p.p_partkey = ps.ps_partkey and p.p_size = 15 and p.p_type like '%BRASS' ;


The filter operator also appear in the query multiple times.

 Filter Operator
        predicate:
            expr: (p_type like '%BRASS')
             type: boolean
                     Filter Operator
                        predicate:
                          expr: (p_size = 15)
                          type: boolean
                         Filter Operator
                           predicate:
                              expr: ((p_size = 15) and (p_type like '%BRASS'))
                              type: boolean
                            TableScan
                              alias: p


Thanks a lot!

Yingyi