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from __future__ import absolute_import, division, print_function
import pytest

from tests.common.custom_cluster_test_suite import CustomClusterTestSuite
from tests.common.impala_cluster import ImpalaCluster
from tests.verifiers.metric_verifier import MetricVerifier


class TestExchangeEos(CustomClusterTestSuite):
  """ Test to verify that the senders' fragments get unblocked and run to completion
  after exchange node hits eos"""

  @classmethod
  def get_workload(cls):
    return 'tpch'

  @classmethod
  def add_test_dimensions(cls):
    super(CustomClusterTestSuite, cls).add_test_dimensions()
    cls.ImpalaTestMatrix.add_constraint(lambda v:
        v.get_value('table_format').file_format == 'parquet')

  @pytest.mark.execute_serially
  @CustomClusterTestSuite.with_args(cluster_size=9, num_exclusive_coordinators=1)
  def test_exchange_eos(self, vector):
    """ Test IMPALA-8845: runs with result spooling enabled and defers the fetching
    of results until all non-coordinator fragments have completed. It aims to verify
    that once the coordinator fragment reaches eos, the rest of the fragments will
    get unblocked. Using a cluster of size 9 which can reliably reproduce the hang of
    some non-coordinator fragments without the fix of IMPALA-8845.
    """

    cluster = ImpalaCluster.get_e2e_test_cluster()
    coordinator = cluster.get_first_impalad()
    client = coordinator.service.create_hs2_client()

    vector.get_value('exec_option')['spool_query_results'] = 'true'
    for query in ["select * from tpch.lineitem order by l_orderkey limit 10000",
                  "select * from tpch.lineitem limit 10000"]:
      handle = self.execute_query_async_using_client(client, query, vector)
      for impalad in ImpalaCluster.get_e2e_test_cluster().impalads:
        verifier = MetricVerifier(impalad.service)
        if impalad.get_webserver_port() == coordinator.get_webserver_port():
          num_fragments = 1
        else:
          num_fragments = 0
        verifier.wait_for_metric("impala-server.num-fragments-in-flight", num_fragments)
      results = client.fetch(query, handle)
      assert results.success
      assert len(results.data) == 10000
    client.close()