PHOENIX-7859 Make ParallelPhoenixConnectionFallbackIT deterministic

phoenix-core/src/it/java/org/apache/phoenix/jdbc/ParallelPhoenixConnectionFallbackIT.java

@@ -23,16 +23,19 @@
 import static org.apache.phoenix.jdbc.HighAvailabilityPolicy.PARALLEL;
 import static org.apache.phoenix.jdbc.HighAvailabilityTestingUtility.HBaseTestingUtilityPair;
 import static org.apache.phoenix.jdbc.HighAvailabilityTestingUtility.doTestBasicOperationsWithConnection;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
+import java.util.List;
 import java.util.Properties;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
+import java.util.concurrent.ThreadPoolExecutor;
 import java.util.function.Supplier;
 import org.apache.phoenix.end2end.NeedsOwnMiniClusterTest;
 import org.junit.AfterClass;
@@ -108,9 +111,27 @@ public void testParallelConnectionBackoff() throws Exception {
     Future<Connection> futureConnB =
       executor.submit(() -> DriverManager.getConnection(jdbcUrl, PROPERTIES));
 
-    // The previous call of connection creation should fill the queue by half.
-    waitFor(() -> !PhoenixHAExecutorServiceProvider.hasCapacity(PROPERTIES).get(0)
-      && !PhoenixHAExecutorServiceProvider.hasCapacity(PROPERTIES).get(1), 100, 5000);
+    // PHOENIX-7859: Poll actual queue state, not the hasCapacity() composite — the multi-step
+    // calculation (size/capacity < threshold) had a race window. We now check queue.size()
+    // directly, then verify hasCapacity() matches expectations.
+    // Note: queueSize >= 1 triggers !hasCapacity() because HA_MAX_QUEUE_SIZE=2 and
+    // HA_THREADPOOL_QUEUE_BACKOFF_THRESHOLD=0.5, so 1/2 = 0.5 which is NOT < 0.5.
+    waitFor(() -> {
+      List<PhoenixHAExecutorServiceProvider.PhoenixHAClusterExecutorServices> services =
+          PhoenixHAExecutorServiceProvider.get(PROPERTIES);
+      int queueSize1 = ((ThreadPoolExecutor) services.get(0).getExecutorService()).getQueue().size();
+      int queueSize2 = ((ThreadPoolExecutor) services.get(1).getExecutorService()).getQueue().size();
+
+      LOG.debug("Waiting for queues to fill: cluster1 queue={}, cluster2 queue={}",
+          queueSize1, queueSize2);
+
+      return queueSize1 >= 1 && queueSize2 >= 1;
+    }, 100, 5000);
+
+    // Verify that hasCapacity() now correctly reports no capacity
+    List<Boolean> capacity = PhoenixHAExecutorServiceProvider.hasCapacity(PROPERTIES);
+    assertFalse("Cluster 1 should have no capacity after queues filled", capacity.get(0).booleanValue());
+    assertFalse("Cluster 2 should have no capacity after queues filled", capacity.get(1).booleanValue());
 
     // This should be backed off now, as the capacity is not available.
     Connection connC = DriverManager.getConnection(jdbcUrl, PROPERTIES);