Examples with GATHER com.facebook.presto.sql.planner.plan.ExchangeNode.Type.GATHER used on opensource projects

Example 1 with GATHER

use of com.facebook.presto.sql.planner.plan.ExchangeNode.Type.GATHER in project presto by prestodb.

the class TestUnion method testUnionUnderTopN.

@Test
public void testUnionUnderTopN() {
    Plan plan = plan("SELECT * FROM (" + "   SELECT regionkey FROM nation " + "   UNION ALL " + "   SELECT nationkey FROM nation" + ") t(a) " + "ORDER BY a LIMIT 1", LogicalPlanner.Stage.OPTIMIZED_AND_VALIDATED, false);
    List<PlanNode> remotes = searchFrom(plan.getRoot()).where(TestUnion::isRemoteExchange).findAll();
    assertEquals(remotes.size(), 1, "There should be exactly one RemoteExchange");
    assertEquals(((ExchangeNode) Iterables.getOnlyElement(remotes)).getType(), GATHER);
    int numberOfpartialTopN = searchFrom(plan.getRoot()).where(planNode -> planNode instanceof TopNNode && ((TopNNode) planNode).getStep().equals(TopNNode.Step.PARTIAL)).count();
    assertEquals(numberOfpartialTopN, 2, "There should be exactly two partial TopN nodes");
    assertPlanIsFullyDistributed(plan);
}