cost_trace explain has unnecessary item #61127

explain format='cost_trace' select
        o_orderpriority,
        count(*) as order_count
from
        orders
where
        o_orderdate >= '1995-01-01'
        and o_orderdate < date_add('1995-01-01', interval '3' month)
        and exists (
                select    *
                from
                        lineitem
                where
                        l_orderkey = o_orderkey
                        and l_commitdate < l_receiptdate  )
group by  o_orderpriority
order by       o_orderpriority

(((((((cpu(1*filters(1)*tikv_cpu_factor(49.9))) + (scan(1*logrowsize(291)*tikv_scan_factor(40.7)))) + (net(0.8*rowsize(24)*tidb_kv_net_factor(3.96))))/15.00)*2852410.25)/6.00) + (cpu(2.2819282e+06*filters(0)*tidb_cpu_factor(49.9))) + ((hashkey(2.2819282e+06*0*tidb_cpu_factor(49.9))) + (hashmem(2.2819282e+06*24*tidb_mem_factor(0.2))) + (hashbuild(2.2819282e+06*tidb_cpu_factor(49.9)))))

***************************[ 4. row ]***************************
id            |     └─IndexJoin_29
estRows       | 2281928.20
estCost       | 1482782425.72
costFormula   | (cpu(10*3*tidb_cpu_factor(49.9))) + (((((scan(2.85241025e+06*logrowsize(46.17)*tiflash_scan_factor(11.6))) + (scan(10000*logrowsize(46.17)*tiflash_scan_factor(11.6))))) + (net(2.85241025e+06*rowsize(46.17)*tidb_flash_net_factor(2.2))))/15.00) + (cpu(2.85241025e+06*filters(0)*tidb_cpu_factor(49.9))) + (cpu(2.85241025e+06*10*tidb_cpu_factor(49.9))) + ((() + ((((((cpu(1*filters(1)*tikv_cpu_factor(49.9))) + (scan(1*logrowsize(291)*tikv_scan_factor(40.7)))) + (net(0.8*rowsize(24)*tidb_kv_net_factor(3.96))))/15.00)*2852410.25)/6.00) + (cpu(2.2819282e+06*filters(0)*tidb_cpu_factor(49.9))) + ((hashkey(2.2819282e+06*0*tidb_cpu_factor(49.9))) + (hashmem(2.2819282e+06*24*tidb_mem_factor(0.2))) + (hashbuild(2.2819282e+06*tidb_cpu_factor(49.9)))))/5.00)
task          | root
access object |
operator info | semi join, inner:TableReader_25, left side:TableReader_61, outer key:test.orders.o_orderkey, inner key:test.lineitem.l_orderkey, equal cond:eq(test.orders.o_orderkey, test.lineitem.l_orderkey)

(() + ((((((cpu(1*filters(1)*tikv_cpu_factor(49.9))) + (scan(1*logrowsize(291)*tikv_scan_factor(40.7)))) + (net(0.8*rowsize(24)*tidb_kv_net_factor(3.96))))/15.00)*2852410.25)/6.00) + (cpu(2.2819282e+06*filters(0)*tidb_cpu_factor(49.9))) + ((hashkey(2.2819282e+06*0*tidb_cpu_factor(49.9))) + (hashmem(2.2819282e+06*24*tidb_mem_factor(0.2))) + (hashbuild(2.2819282e+06*tidb_cpu_factor(49.9)))))