[HIVE-5623] ORC accessing array column that's empty will fail with java out of bound exception

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.11.0
• Fix Version/s: 1.3.0, 2.0.0
• Component/s: File Formats
• Labels: orcfile
• Assignee: Prasanth Jayachandran
• Reporter: Eric Chu
• Created: 23/Oct/13 07:39
• Updated: 16/Feb/16 23:51
• Resolved: 14/Sep/15 21:09

Description

In our ORC tests we saw that queries that work on RCFile failed on the corresponding ORC version with Java IndexOutOfBoundsException in OrcStruct.java. The queries failed b/c the table has an array type column and there are rows with an empty array. We noticed that the getList(Object list, int i) method in OrcStruct.java simply returns the i-th element from list without checking if list is not null or if i is within valid range. After fixing that the queries run fine. The fix is really simple, but maybe there are other similar cases that need to be handled.
The fix is to check if listObj is null and if i falls within range:

    public Object getListElement(Object listObj, int i) {
      if (listObj == null) {
          return null;
      }
      List list = ((List) listObj);
      if (i < 0 || i >= list.size()) {
          return null;
      }
      return list.get(i);
    }

Issue Links

• is part of: HIVE-8846 Null checks missing in ORC list and map object inpsectors