@Test
  public void testCacheOpAfterQueryCancel() throws Exception {
    int locatorPort = locator.getPort();
    // start up more servers
    MemberVM server3 = cluster.startServerVM(3, locatorPort);

    server3.invoke(() -> {
      DefaultQuery.testHook = QueryMonitorDUnitTest::delayQueryTestHook;
      GemFireCacheImpl.MAX_QUERY_EXECUTION_TIME = MAX_QUERY_EXECUTE_TIME;
    });

    gfsh.executeAndAssertThat("create region --name=exampleRegion --type=REPLICATE")
        .statusIsSuccess();
    locator.waitUntilRegionIsReadyOnExactlyThisManyServers(SEPARATOR + "exampleRegion", 3);

    server1.invoke(() -> {
      QueryService queryService = ClusterStartupRule.getCache().getQueryService();
      queryService.createIndex("statusIndex", "status", SEPARATOR + "exampleRegion");
      queryService.createIndex("secIdIndex", "pos.secId",
          SEPARATOR + "exampleRegion p, p.positions.values pos");
      populateRegion(100, 1000);
    });

    AsyncInvocation<Void> ai1 = server1.invokeAsync(() -> {
      for (int j = 0; j < 5; j++) {
        populateRegion(0, 2000);
      }
    });

    AsyncInvocation<Void> ai2 = server2.invokeAsync(() -> {
      for (int j = 0; j < 5; j++) {
        populateRegion(1000, 3000);
      }
    });

    // server3 performs a region put after a query is canceled.
    AsyncInvocation<Void> ai3 = server3.invokeAsync(() -> {
      Region exampleRegion = ClusterStartupRule.getCache().getRegion("exampleRegion");
      QueryService queryService = GemFireCacheImpl.getInstance().getQueryService();
      String qStr =
          "SELECT DISTINCT * FROM " + SEPARATOR
              + "exampleRegion p, p.positions.values pos1, p.positions.values pos"
              + " where p.ID < pos.sharesOutstanding OR p.ID > 0 OR p.position1.mktValue > 0 "
              + " OR pos.secId in SET ('SUN', 'IBM', 'YHOO', 'GOOG', 'MSFT', "
              + " 'AOL', 'APPL', 'ORCL', 'SAP', 'DELL', 'RHAT', 'NOVL', 'HP')"
              + " order by p.status, p.ID desc";
      for (int i = 0; i < 100; i++) {
        try {
          Query query = queryService.newQuery(qStr);
          query.execute();
          fail("The query should have been canceled by the QueryMonitor. Query: " + qStr);
        } catch (QueryExecutionTimeoutException qet) {
          exampleRegion.put("" + i, new Portfolio(i));
        }
      }
    });

    ai1.await();
    ai2.await();
    ai3.await();

    server3.invoke(() -> {
      DefaultQuery.testHook = null;
      GemFireCacheImpl.MAX_QUERY_EXECUTION_TIME = -1;
    });
  }
These tests add a test hook to make sure query execution sleeps for at least 20 ms, so the
queryMonitor thread will get a chance to cancel the query before it completes.

The MAX_QUERY_EXECUTION_TIME is set as 1 ms, i.e, theoretically all queries will be cancelled
after 1ms, but due to thread scheduling, this may not be true. we can only decrease the flakyness
of the test by making MAX_QUERY_EXECUTION_TIME the smallest possible (1) and making the query
execution time longer (but not too long to make the test run too slow).
geode-cq/src/distributedTest/java/org/apache/geode/cache/query/dunit/QueryMonitorDUnitTest.java