Hi tony, Could you please provide the simple reproduce steps so that we can easily debug in our own env.?
Thanks, Zhenglin 2017-05-18 14:17 GMT+08:00 tao tony <[email protected]>: > it seems a bug for querying on an external table because I found > ucloud_pay_tenanid ulist was a external table which using gpfdist. > > CREATE EXTERNAL TABLE ucloud_pay_tenanid ( > customercode character varying(255), > customername character varying(255), > prefixflag character varying(255), > customertype character varying(255), > comments character varying(255) > ) LOCATION ( > 'gpfdist://hdptest02.hddomain.cn:8087/ucloud_pay_tenanid_*.csv' > ) FORMAT 'text' (delimiter E';' null E'' escape E'OFF') > ENCODING 'UTF8'; > > then I create an internal table using: > > create table ucloudtest as select * from ucloud_pay_tenanid; > > run the explain,it lookks like the right query plan: > > hdb=# explain select cp.tenantid, > hdb-# (select ulist.customertype from ucloudtest ulist where > ulist.customercode=cp.tenantid),cp.orderuuid from cptest cp; > QUERY PLAN > ------------------------------------------------------------ > --------------------------------------------- > Gather Motion 1:1 (slice2; segments: 1) (cost=0.00..219.50 rows=100 > width=42) > -> Append-only Scan on cptest cp (cost=0.00..219.50 rows=100 > width=42) > SubPlan 1 > -> Result (cost=2.18..2.19 rows=1 width=7) > Filter: ulist.customercode::text = $0::text > -> Materialize (cost=2.18..2.19 rows=1 width=7) > -> Broadcast Motion 1:1 (slice1; segments: 1) > (cost=0.00..2.17 rows=1 width=7) > -> Append-only Scan on ucloudtest ulist > (cost=0.00..2.17 rows=1 width=7) > Settings: default_hash_table_bucket_number=18; optimizer=off > Optimizer status: legacy query optimizer > (10 rows) > > run the query,get the correct result: > > hdb=# select cp.tenantid, > (select ulist.customertype from ucloudtest ulist where > ulist.customercode=cp.tenantid),cp.orderuuid from cptest cp; > tenantid | ?column? | orderuuid > ----------+----------+---------------------------------- > sxve7r6c | 便利 | e6d9b57a0c55484392448ea908c1fe49 > sxve7r6c | 便利 | 22a80697bfc74d63b7f28eee246c4368 > 3e7rph46 | 专卖 | 420ad3e45762459e91860b975e9f2751 > 3e7rph46 | 专卖 | 0634e7e3539a4116b9917a7493838f51 > 7jvfka5m | 专卖 | a7b96194fe9f48379e2711ac6000191b > 6xydfh4y | 便利 | 7a55e97119784623a53f6e65ef9680c7 > sxve7r6c | 便利 | 227f3d22aec14723bb51efc4e2a6f0b4 > 3e7rph46 | 专卖 | f3d02cc77a2348829be2f72ce24bf846 > 6xydfh4y | 便利 | bab722ac7d5748408d3ad2973d292ab5 > > > On 05/18/2017 11:11 AM, tao tony wrote: > > hi guys, > > > > The different explains as below make me confused these days,could you > > please help me to explain why ulist.customertype is null. > > > > explain : > > > > hdb=# explain select cp.tenantid, > > (select ulist.customertype from ucloud_pay_tenanid ulist where > > ulist.customercode=cp.tenantid),cp.orderuuid from cptest cp; > > QUERY PLAN > > ------------------------------------------------------------ > -------------------------------------- > > Gather Motion 18:1 (slice1; segments: 18) (cost=0.00..1350002.00 > > rows=100 width=42) > > -> Append-only Scan on cptest cp (cost=0.00..1350002.00 rows=6 > > width=42) > > SubPlan 1 > > -> External Scan on ucloud_pay_tenanid ulist > > (cost=0.00..13500.00 rows=56 width=516) > > Filter: customercode::text = $0::text > > Settings: default_hash_table_bucket_number=18; optimizer=off > > Optimizer status: legacy query optimizer > > (7 rows) > > > > > > hdb=# explain select a,(select d from test1 s where t.b=s.e) from test2 > t; > > QUERY PLAN > > ------------------------------------------------------------ > --------------------------------------------- > > Gather Motion 1:1 (slice2; segments: 1) (cost=0.00..10.20 rows=9 > > width=6) > > -> Append-only Scan on test2 t (cost=0.00..10.20 rows=9 width=6) > > SubPlan 1 > > -> Result (cost=1.01..1.02 rows=1 width=4) > > Filter: $0::text = s.e::text > > -> Materialize (cost=1.01..1.02 rows=1 width=4) > > -> Broadcast Motion 1:1 (slice1; segments: 1) > > (cost=0.00..1.01 rows=1 width=4) > > -> Append-only Scan on test1 s > > (cost=0.00..1.01 rows=1 width=4) > > Settings: default_hash_table_bucket_number=18; optimizer=off > > Optimizer status: legacy query optimizer > > (10 rows) > > > > test data: > > > > query1: > > > > hdb-# (select ulist.customertype from ucloud_pay_tenanid ulist where > > ulist.customercode=cp.tenantid),cp.orderuuid from cptest cp; > > tenantid | ?column? | orderuuid > > ----------+----------+---------------------------------- > > sxve7r6c | | 901cf777a3144907899226de86ab8cfe > > k5r9qcfj | | 54c8cbdbe64f4dcca5cacb40b7ab52d6 > > 3e7rph46 | | f5e777a5189e409da607182d059ec0d5 > > 3e7rph46 | | 478d8a0921ab444ca80dc03ce97d3a94 > > 3e7rph46 | | 25808c4a66e34ecaad02d2fc183920ca > > 3e7rph46 | | 0a62832067ea4db68641cce35385aae7 > > 3e7rph46 | | 4c9e91233af947518c5c5767a2bd8b3c > > 6xydfh4y | | b2fa1af123384452b23bbc5e0794da56 > > 6xydfh4y | | ade5731d97044a0eb9d74836ea7dbf48 > > pejg93wh | | da2d037765bb4262a82764715cb4453d > > sxve7r6c | | b02df6c998ff4e448b575e3b1fae8e35 > > 3e7rph46 | | 4c9e91233af947518c5c5767a2bd8b3c > > > > query 2: > > > > hdb=# select a,(select d from test1 s where t.b=s.e) from test2 t; > > a | ?column? > > ---+---------- > > 1 | 1 > > 2 | 2 > > 3 | 3 > > 4 | 4 > > 5 | 5 > > 6 | 7 > > 7 | 8 > > 8 | 9 > > 9 | 10 > > (9 rows) > > > > another query equal to query1,customertype is not null: > > > > hdb=# select tenantid,ulist.customertype,cp.orderuuid from cptest > > cp,ucloud_pay_tenanid ulist > > hdb-# where cp.tenantid = ulist.customercode; > > tenantid | customertype | orderuuid > > ----------+--------------+---------------------------------- > > 7jvfka5m | 专卖 | f10771c9eb4e434dadcc82dc7cda0d4d > > 7jvfka5m | 专卖 | 246a13ed45174ee083fd9f743532ab4c > > 7jvfka5m | 专卖 | e2687954d3e94ab0bf1366369bdc9887 > > 7jvfka5m | 专卖 | 018ef9e35db94901b4822509494bd6b5 > > 7jvfka5m | 专卖 | 9054d2d5d7264a8aa4b41baddf1198e8 > > 7jvfka5m | 专卖 | 9054d2d5d7264a8aa4b41baddf1198e8 > > 7jvfka5m | 专卖 | a7b96194fe9f48379e2711ac6000191b > > u642nk35 | 便利 | df4ef8599c154c978d021b6765edb55b > > u642nk35 | 便利 | d60c5d3ac0f44ef1a278d50d84847c2f > > u642nk35 | 便利 | df6ca3d8fb444f8fba604db8611c6292 > > u642nk35 | 便利 | df4ef8599c154c978d021b6765edb55b > > > >
