[DRILL-7358] Text reader returns nothing for count queries over empty files

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.16.0
• Fix Version/s: 1.17.0
• Labels: ready-to-commit
• Assignee: Paul Rogers
• Reporter: Arina Ielchiieva
• Reviewer: Arina Ielchiieva
• Created: 22/Aug/19 16:24
• Updated: 07/Oct/19 12:46
• Resolved: 07/Oct/19 12:46

Description

If we do count over empty CSV files (with or without headers), there is no result.
Though expecting result is 0.

Unit tests examples:

@Test
public void testCount() throws Exception {
  String fileName = "headersOnly.csv";
  try (PrintWriter out = new PrintWriter(new FileWriter(new File(testDir, fileName)))) {
    out.print("a,b,c"); // note: no \n in the end
  }

  queryBuilder().sql("SELECT count(1) FROM `dfs.data`.`" + fileName + "`").print();
}

@Test
public void testCount() throws Exception {
  String fileName = "empty.csv";

  File file = new File(testDir, fileName);
  assertTrue(file.createNewFile());

  queryBuilder().sql("SELECT count(1) FROM `dfs.data`.`" + fileName + "`").print();
}

Issue Links

• links to: GitHub Pull Request #1867