tests/custom_cluster/test_session_expiration.py

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# Tests for query expiration.

import pytest
from time import sleep

from tests.common.custom_cluster_test_suite import CustomClusterTestSuite

class TestSessionExpiration(CustomClusterTestSuite):
  """Tests query expiration logic"""

  @pytest.mark.execute_serially
  @CustomClusterTestSuite.with_args("--idle_session_timeout=6")
  def test_session_expiration(self, vector):
    impalad = self.cluster.get_any_impalad()
    # setup_class creates an Impala client to <hostname>:21000 after the cluster starts.
    # The client expires at the same time as the client created below. Since we choose the
    # impalad to connect to randomly, the test becomes flaky, as the metric we expect to
    # be incremented by 1 gets incremented by 2 if both clients are connected to the same
    # Impalad.
    self.client.close()
    num_expired = impalad.service.get_metric_value("impala-server.num-sessions-expired")
    client = impalad.service.create_beeswax_client()
    # Sleep for half the expiration time to confirm that the session is not expired early
    # (see IMPALA-838)
    sleep(3)
    assert num_expired == impalad.service.get_metric_value(
      "impala-server.num-sessions-expired")
    # Wait for session expiration. Impala will poll the session expiry queue every second
    impalad.service.wait_for_metric_value(
      "impala-server.num-sessions-expired", num_expired + 1, 20)

  @pytest.mark.execute_serially
  @CustomClusterTestSuite.with_args("--idle_session_timeout=3")
  def test_session_expiration_with_set(self, vector):
    impalad = self.cluster.get_any_impalad()
    self.client.close()
    num_expired = impalad.service.get_metric_value("impala-server.num-sessions-expired")

    # Test if we can set a shorter timeout than the process-wide option
    client = impalad.service.create_beeswax_client()
    client.execute("SET IDLE_SESSION_TIMEOUT=1")
    sleep(2.5)
    assert num_expired + 1 == impalad.service.get_metric_value(
      "impala-server.num-sessions-expired")

    # Test if we can set a longer timeout than the process-wide option
    client = impalad.service.create_beeswax_client()
    client.execute("SET IDLE_SESSION_TIMEOUT=10")
    sleep(5)
    assert num_expired + 1 == impalad.service.get_metric_value(
      "impala-server.num-sessions-expired")


  @pytest.mark.execute_serially
  @CustomClusterTestSuite.with_args("--idle_session_timeout=5")
  def test_unsetting_session_expiration(self, vector):
    impalad = self.cluster.get_any_impalad()
    self.client.close()
    num_expired = impalad.service.get_metric_value("impala-server.num-sessions-expired")

    # Test unsetting IDLE_SESSION_TIMEOUT
    client = impalad.service.create_beeswax_client()
    client.execute("SET IDLE_SESSION_TIMEOUT=1")

    # Unset to 5 sec
    client.execute('SET IDLE_SESSION_TIMEOUT=""')
    sleep(2)
    # client session should be alive at this point
    assert num_expired == impalad.service.get_metric_value(
      "impala-server.num-sessions-expired")
    sleep(5)
    # now client should have expired
    assert num_expired + 1 == impalad.service.get_metric_value(
      "impala-server.num-sessions-expired")

  @pytest.mark.execute_serially
  @CustomClusterTestSuite.with_args("-default_pool_max_requests 1")
  def test_session_expiration_with_queued_query(self, vector):
    """Ensure that a query waiting in queue gets cancelled if the session expires."""
    impalad = self.cluster.get_any_impalad()
    client = impalad.service.create_beeswax_client()
    client.execute("SET IDLE_SESSION_TIMEOUT=3")
    client.execute_async("select sleep(10000)")
    queued_handle = client.execute_async("select 1")
    impalad.service.wait_for_metric_value(
      "admission-controller.local-num-queued.default-pool", 1)
    sleep(3)
    impalad.service.wait_for_metric_value(
      "admission-controller.local-num-queued.default-pool", 0)
    impalad.service.wait_for_metric_value(
      "admission-controller.agg-num-running.default-pool", 0)
    queued_query_profile = impalad.service.create_beeswax_client().get_runtime_profile(
      queued_handle)
    assert "Admission result: Cancelled (queued)" in queued_query_profile