[HBASE-13779] Calling table.exists() before table.get() end up with an empty Result

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.1.0, 1.2.0, 0.98.12.1, 2.0.0
• Fix Version/s: 0.98.13, 1.0.2, 1.2.0, 1.1.1, 2.0.0
• Component/s: Client
• Assignee: Matteo Bertozzi
• Reporter: Matteo Bertozzi
• Created: 26/May/15 16:53
• Updated: 18/Dec/15 05:12
• Resolved: 05/Jun/15 19:39

Description

If we call exists() before a get() the result returned by the get() will be empty.
simple test to verify it:

Put put = new Put(ROW);
put.add(FAMILY, QUALIFIER, VALUE);
table.put(put);

Get get = new Get(ROW);

boolean exist = table.exists(get);
exist = table.exists(get);
assertEquals(true, exist);

Result result = table.get(get);
// this will fail saying that the Result is empty
// if we remove the exist everything is fine
assertEquals(false, result.isEmpty()); 
assertTrue(Bytes.equals(VALUE, result.getValue(FAMILY, QUALIFIER)));

if we use a different Get instance for the get everything works

...
get = new Get(ROW);
Result result = table.get(get);
assertEquals(false, result.isEmpty()); 

HTable.exists() set the checkExistenceOnly flag in the Get so that object is not reusable by a table.get()

  public boolean exists(final Get get) throws IOException {
    get.setCheckExistenceOnly(true);
    Result r = get(get);
    assert r.getExists() != null;
    return r.getExists();
  }

Issue Links

• is related to: HBASE-13799 javadoc how Scan gets polluted when used; if you set attributes or ask for scan metrics