hongbin ma created KYLIN-1792:
---------------------------------
Summary: behaviours for non-aggregated queries
Key: KYLIN-1792
URL: https://issues.apache.org/jira/browse/KYLIN-1792
Project: Kylin
Issue Type: Improvement
Affects Versions: v1.5.2
Reporter: hongbin ma
Assignee: Yiming Liu
Even though kylin is not designed for non-aggregated queries, people do
frequently use queries like
{code:sql}
select * from fact limit
{code}
to verify their cubes. Recently many new users reported problems when running
such queries, we'll use this JIRA as an umbrella to track all related issues.
for such queries on fact table:
- select * from fact : should return results from base cuboid (thus not raw
fact table data) and MIGHT crash query server or region server
- select * from fact limit x : should return results from base cuboid (thus
not raw fact table data) and SHOULD NOT crash query server or region server.
Current there's a known issue KYLIN-1787 fails to push down the limit value
- select a,b from fact: should return results from base cuboid (thus not raw
fact table data) and MIGHT crash query server or region server (when a or b
contains is a measure, the query only works when you defined a sum() measure )
- select a,b from fact limit x: should return results from base cuboid (thus
not raw fact table data) and SHOULD NOT crash query server or region server
(when a or b contains is a measure, the query only works when you defined a
sum() measure)
such four kinds of queries on look up tables should return correct results from
the lookup table snapshot directly, and even without the limit clause, they
have a low possibility to crash query server or region server because lookup
table tends to be small. However, it's still better to make sure limit is
taking effect.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
