[KYLIN-751] Max on negative double values is not working

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: v0.7.1
• Fix Version/s: v1.0, v1.4.0
• Component/s: Query Engine, REST Service
• Assignee: liyang
• Reporter: Huang Hua
• Created: 06/May/15 03:33
• Updated: 06/Sep/15 07:11
• Resolved: 19/Aug/15 01:25

Description

I spent some time to debug the kylin code and I think it's very likely a bug in Query module. It keeps returning 4.9E-324 for max of negative values.

The cube and the fact table was illustrated before in the last couple emails. The query I used was "select id, sum(trans_at), max(trans_at) from max_neg group by id;".

When the query hit the rest server, it will be passed to the function "private SQLResponse execute(String sql, SQLRequest sqlRequest)" of "QueryService" class in kylin-server module.
And in that function, it utilizes the calcite to parse the sql and the kylin-storage module to actually fetch data from hbase. However, the following codes of the function packages wrong results.
while (resultSet.next()) {
for (int i = 0; i < columnCount; i++)

{ oneRow.add((resultSet.getString(i + 1))); -- This produce wrong result like [2c9083862fe1d8f00130062167480ce8-213582789, -86.4, 4.9E-324] }

results.add(new LinkedList<String>(oneRow));
oneRow.clear();
}

I also checked the related functions of kylin-storage, and the results fetched from hbase were all good, for example, the function "public Tuple next()" of "CubeSegmentTupleIterator" class returned [2c9083862fe1d8f00130062167480ce8-0114097017, -59.0, 1, -59.0] and the function "private Object[] convertCurrentRow(ITuple tuple)" of "CubeEnumerator" class also returned [2c9083862fe1d8f00130062167480ce8-0114097017, -59.0, 1, -59.0] which I think both are correct.

Issue Links

• relates to: CALCITE-735 Primitive.DOUBLE.min should be large and negative