[KYLIN-4191] NPE in StreamingTupleConverter when querying count on a dimension field

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: v3.0.0-alpha
• Fix Version/s: Future
• Component/s: Real-time Streaming
• Assignee: Xiaoxiang Yu
• Reporter: Andras Istvan Nagy
• Created: 11/Oct/19 08:19
• Updated: 05/Dec/19 08:43

Description

I am using the real-time olap feature with a lambda datasource definition. When executing a query that has a count(dim_field) in the select clause, where "dim_field" is one of the dimension fields, I get a NPE from org.apache.kylin.stream.core.query.StreamingTupleConverter.

(According to a colleague, a similar query used to work for some time in our environment, and then stopped working, but I can't verify this statement. Restarting the Kylin processes or disabling/enabling the cube does not "fix" the issue.)

The relevant part of stacktrace seems to be:

Caused by: java.lang.NullPointerException at org.apache.kylin.stream.core.query.StreamingTupleConverter.<init>(StreamingTupleConverter.java:86)

Please see attached full stacktrace.