Query leads to endless loop (because of Optimizer?)

[tcm-marcel]

Running TPC-H Q13 leads to an endless loop in peloton. I tried to follow the execution path and it seems to me that the optimizer runs in infinitely many tasks and the actual execution never starts. However, I am not familiar with this part of peloton.

TPC-H Q13 (includes creating schema)

CREATE TABLE nation  ( n_nationkey  INTEGER NOT NULL,
                       n_name       CHAR(25) NOT NULL,
                       n_regionkey  INTEGER NOT NULL,
                       n_comment    VARCHAR(152));

CREATE TABLE region  ( r_regionkey  INTEGER NOT NULL,
                       r_name       CHAR(25) NOT NULL,
                       r_comment    VARCHAR(152));

CREATE TABLE part  ( p_partkey     INTEGER NOT NULL,
                     p_name        VARCHAR(55) NOT NULL,
                     p_mfgr        CHAR(25) NOT NULL,
                     p_brand       CHAR(10) NOT NULL,
                     p_type        VARCHAR(25) NOT NULL,
                     p_size        INTEGER NOT NULL,
                     p_container   CHAR(10) NOT NULL,
                     p_retailprice DECIMAL(15,2) NOT NULL,
                     p_comment     VARCHAR(23) NOT NULL );

CREATE TABLE supplier ( s_suppkey     INTEGER NOT NULL,
                        s_name        CHAR(25) NOT NULL,
                        s_address     VARCHAR(40) NOT NULL,
                        s_nationkey   INTEGER NOT NULL,
                        s_phone       CHAR(15) NOT NULL,
                        s_acctbal     DECIMAL(15,2) NOT NULL,
                        s_comment     VARCHAR(101) NOT NULL);

CREATE TABLE partsupp ( ps_partkey     INTEGER NOT NULL,
                        ps_suppkey     INTEGER NOT NULL,
                        ps_availqty    INTEGER NOT NULL,
                        ps_supplycost  DECIMAL(15,2)  NOT NULL,
                        ps_comment     VARCHAR(199) NOT NULL );

CREATE TABLE customer ( c_custkey     INTEGER NOT NULL,
                        c_name        VARCHAR(25) NOT NULL,
                        c_address     VARCHAR(40) NOT NULL,
                        c_nationkey   INTEGER NOT NULL,
                        c_phone       CHAR(15) NOT NULL,
                        c_acctbal     DECIMAL(15,2)   NOT NULL,
                        c_mktsegment  CHAR(10) NOT NULL,
                        c_comment     VARCHAR(117) NOT NULL);

CREATE TABLE orders  ( o_orderkey       INTEGER NOT NULL,
                       o_custkey        INTEGER NOT NULL,
                       o_orderstatus    CHAR(1) NOT NULL,
                       o_totalprice     DECIMAL(15,2) NOT NULL,
                       o_orderdate      DATE NOT NULL,
                       o_orderpriority  CHAR(15) NOT NULL,  
                       o_clerk          CHAR(15) NOT NULL, 
                       o_shippriority   INTEGER NOT NULL,
                       o_comment        VARCHAR(79) NOT NULL);

CREATE TABLE lineitem ( l_orderkey    INTEGER NOT NULL,
                        l_partkey     INTEGER NOT NULL,
                        l_suppkey     INTEGER NOT NULL,
                        l_linenumber  INTEGER NOT NULL,
                        l_quantity    DECIMAL(15,2) NOT NULL,
                        l_extendedprice  DECIMAL(15,2) NOT NULL,
                        l_discount    DECIMAL(15,2) NOT NULL,
                        l_tax         DECIMAL(15,2) NOT NULL,
                        l_returnflag  CHAR(1) NOT NULL,
                        l_linestatus  CHAR(1) NOT NULL,
                        l_shipdate    DATE NOT NULL,
                        l_commitdate  DATE NOT NULL,
                        l_receiptdate DATE NOT NULL,
                        l_shipinstruct CHAR(25) NOT NULL,
                        l_shipmode     CHAR(10) NOT NULL,
                        l_comment      VARCHAR(44) NOT NULL);

select
	c_count,
	count(*) as custdist
from
	(
		select
			c_custkey,
			count(o_orderkey) as c_count
		from
			customer left outer join orders on
				c_custkey = o_custkey
				and o_comment not like '%special%deposits%'
		group by
			c_custkey
	) as c_orders
group by
	c_count
order by
	count(*) desc,
	c_count desc;

[tcm-marcel]

@chenboy can you take a look at this?

[GustavoAngulo]

@tcm-marcel The loop is caused because this query contains a Left Outer Join. A group in 15721 is working on implementing outer joins in the optimizer (#1280) so it should hopefully be fixed soon. I'll keep the issue open for now.

For the future though we should probably throw an exception for unimplemented SQL functions in the optimizer instead of looping.

[tcm-marcel]

Great, thank you!