[KYLIN-1419] NullPointerException occurs when query from subqueries with order by

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: v1.2
• Fix Version/s: v1.3.0, v1.4.0, v1.5.0
• Component/s: Query Engine
• Assignee: nichunen
• Reporter: nichunen
• Created: 15/Feb/16 08:29
• Updated: 14/Mar/16 04:54
• Resolved: 07/Mar/16 06:18

Description

Context may not have table scan which is created by OLAPJoinRel, so it does not have realization. In org.apache.kylin.query.relnode.OLAPSortRel#findMeasure, it visits "this.context.realization" directly, so makes the NullPointerException. For example, query like "select a.LSTG_FORMAT_NAME from (select LEAF_CATEG_ID,LSTG_FORMAT_NAME from KYLIN_SALES)a, (select LEAF_CATEG_ID,PART_DT from KYLIN_SALES)b order by a.LSTG_FORMAT_NAME".

Attached is the patch to fix, added a null protection.