[TAJO-1239] ORDER BY with null column desc miss some data.

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.10.0
• Component/s: Physical Operator, Planner/Optimizer
• Assignee: Hyoungjun Kim
• Reporter: Hyoungjun Kim
• Created: 09/Dec/14 15:50
• Updated: 12/Dec/14 07:14
• Resolved: 12/Dec/14 06:58

Description

TAJO-904 fixed the ORDER BY ascending bug. But descending with null column still miss some data. I tested the following code.

KeyValueSet tableOptions = new KeyValueSet();
tableOptions.set(StorageConstants.TEXT_DELIMITER, StorageConstants.DEFAULT_FIELD_DELIMITER);
tableOptions.set(StorageConstants.TEXT_NULL, "\\\\N");

Schema schema = new Schema();
schema.addColumn("id", Type.INT4);
schema.addColumn("name", Type.TEXT);
String[] data = new String[]{ "1|111", "2|\\N", "3|333" };
TajoTestingCluster.createTable("table11", schema, tableOptions, data, 1);

try {
  ResultSet res = executeString("select * from table11 order by name asc");
  String ascExpected = "id,name\n" +
      "-------------------------------\n" +
      "1,111\n" +
      "3,333\n" +
      "2,null\n";

  assertEquals(ascExpected, resultSetToString(res));
  res.close();

  res = executeString("select * from table11 order by name desc");
  String descExpected = "id,name\n" +
      "-------------------------------\n" +
      "2,null\n" +
      "3,333\n" +
      "1,111\n";

  assertEquals(descExpected, resultSetToString(res));
  res.close();
} finally {
  executeString("DROP TABLE table11 PURGE");
} 

The first query is successful, but the second query will fail.