Jihoon Son created TAJO-2118:
--------------------------------
Summary: The join cost calculation before join order optimization
should be same with that of after optimization
Key: TAJO-2118
URL: https://issues.apache.org/jira/browse/TAJO-2118
Project: Tajo
Issue Type: Bug
Components: Planner/Optimizer
Reporter: Jihoon Son
Priority: Minor
Fix For: 0.12.0
See the title.
When you run the below query,
{noformat}
// TPC-H Q10
default> select
c_custkey,
c_name,
sum(l_extendedprice * (1 - l_discount)) as revenue,
c_acctbal,
n_name,
c_address,
c_phone,
c_comment
from
customer as c
join nation as n
on c.c_nationkey = n.n_nationkey
join orders as o
on c.c_custkey = o.o_custkey and o.o_orderdate >= '1993-10-01'::date
and o.o_orderdate < '1994-01-01'::date
join lineitem as l
on l.l_orderkey = o.o_orderkey and l.l_returnflag = 'R'
group by
c_custkey, c_name, c_acctbal, c_phone, n_name, c_address, c_comment
order by
revenue desc
{noformat}
you can find the below log. The cost of before optimization is smaller than
that after optimization. This is because the different cost calculation methods
are used for each unoptimized and optimized plans.
{noformat}
...
Query Block Graph
-----------------------------
|-#ROOT
-----------------------------
Optimization Log:
[#ROOT]
> Non-optimized join order: (((default.customer200 ⋈θ
default.nation200) ⋈θ default.orders200) ⋈θ default.lineitem200) (cost:
3.19186301858328E32)
> Optimized join order : ((default.lineitem200 ⋈θ default.orders200)
⋈θ (default.customer200 ⋈θ default.nation200)) (cost: 1.0772537685263547E33)
-----------------------------
...
{noformat}
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