[
https://issues.jboss.org/browse/TEIID-3743?page=com.atlassian.jira.plugin...
]
Scott Wallace commented on TEIID-3743:
--------------------------------------
[~shawkins] let me know if you need any other details. The issue is the physical query
generated isn't compatible with Impala, which doesn't allow multiple count
distincts in a single query block. So I think the solution was to use the cross join /
subquery syntax recommended by Cloudera (shown in description).
Multiple Count Distinct Columns Fails for Impala
------------------------------------------------
Key: TEIID-3743
URL:
https://issues.jboss.org/browse/TEIID-3743
Project: Teiid
Issue Type: Bug
Components: Misc. Connectors
Affects Versions: 8.11.4
Reporter: Scott Wallace
Assignee: Steven Hawkins
Fix For: 8.12
Teiid Impala translator incorrectly allows multiple count distinct columns, which fails
to execute since it is not supported by Impala.
Per Cloudera documentation:
{quote}By default, Impala only allows a single COUNT(DISTINCT columns) expression in each
query.
To produce the same result as multiple COUNT(DISTINCT) expressions, you can use the
following technique for queries involving a single table:
select v1.c1 result1, v2.c1 result2 from (select count(distinct col1) as c1 from t1) v1
cross join (select count(distinct col2) as c1 from t1) v2;{quote}
The Teiid-Impala translator should ideally rewrite the query as necessary so that the
query does not fail executing multiple count distincts against Impala.
--
This message was sent by Atlassian JIRA
(v6.4.11#64026)