[IMPALA-5145] CTAS failing when creating from a view with error "Unsupported type 'null_type'"

• Type: Bug
• Status: Resolved
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: Impala 2.7.0, Impala 2.8.0
• Fix Version/s: Impala 2.9.0
• Component/s: Frontend
• Labels: regression
• Target Version: Impala 2.9.0
• Epic Color: ghx-label-8
• Assignee: Anuj Phadke
• Reporter: Boris Gitline
• Created: 31/Mar/17 00:57
• Updated: 21/Apr/17 18:08
• Resolved: 21/Apr/17 18:08

Description

There is an apparent regression in Impala 2.7. The following works in Impala 2.6; but fails in Impala 2.7 and up. Note : students1 is an arbitrary table.

[root@host-10-17-80-137 ~]# impala-shell
Starting Impala Shell without Kerberos authentication
Connected to host-10-17-80-137.coe.cloudera.com:21000
Server version: impalad version 2.7.0-cdh5.10.0 RELEASE (build 785a073cd07e2540d521ecebb8b38161ccbd2aa2)
***********************************************************************************
Welcome to the Impala shell.
(Impala Shell v2.7.0-cdh5.10.0 (785a073) built on Fri Jan 20 12:03:56 PST 2017)

[host-10-17-80-137.coe.cloudera.com:21000] > create view v1_nul_tst as select cast(null as string) col1 from students1;
Query: create view v1_nul_tst as select cast(null as string) col1 from students1
Query submitted at: 2017-03-27 15:17:51 (Coordinator: http://host-10-17-80-137:25000)
Query progress can be monitored at: http://host-10-17-80-137:25000/query_plan?query_id=ed4ef0e6b343d1a9:ad0527c600000000

Fetched 0 row(s) in 0.13s
[host-10-17-80-137.coe.cloudera.com:21000] > create table t1_nul_tst as select * from v1_nul_tst where 1=2;
Query: create table t1_nul_tst as select * from v1_nul_tst where 1=2
Query submitted at: 2017-03-27 15:18:17 (Coordinator: http://host-10-17-80-137:25000)
ERROR: AnalysisException: Unsupported type 'null_type' in column 'col1' of table 't1_nul_tst'
CAUSED BY: TableLoadingException: Unsupported type 'null_type' in column 'col1' of table 't1_nul_tst'

[host-10-17-80-137.coe.cloudera.com:21000] > drop view v1_nul_tst;
Query: drop view v1_nul_tst
[host-10-17-80-137.coe.cloudera.com:21000] > create view v1_nul_tst as select cast(null as varchar(10)) col1 from students1;
Query: create view v1_nul_tst as select cast(null as varchar(10)) col1 from students1
Query submitted at: 2017-03-27 15:21:10 (Coordinator: http://host-10-17-80-137:25000)
Query progress can be monitored at: http://host-10-17-80-137:25000/query_plan?query_id=be4c7f476c73e6d8:2f25ac1100000000

Fetched 0 row(s) in 0.12s

[host-10-17-80-137.coe.cloudera.com:21000] > desc v1_nul_tst;
Query: describe v1_nul_tst
+------+-------------+---------+
| name | type | comment |
+------+-------------+---------+
| col1 | varchar(10) | |
+------+-------------+---------+
Fetched 1 row(s) in 3.76s
[host-10-17-80-137.coe.cloudera.com:21000] > create table t1_nul_tst as select * from v1_nul_tst where 1=2;
Query: create table t1_nul_tst as select * from v1_nul_tst where 1=2
Query submitted at: 2017-03-27 15:21:55 (Coordinator: http://host-10-17-80-137:25000)
ERROR: AnalysisException: Unsupported type 'null_type' in column 'col1' of table 't1_nul_tst'
CAUSED BY: TableLoadingException: Unsupported type 'null_type' in column 'col1' of table 't1_nul_tst'