Add test to measure barging behavior.

hikaricp/src/test/java/com/zaxxer/hikari/BargeTest.java

@@ -0,0 +1,154 @@
+/*
+ * Copyright (C) 2014 Brett Wooldridge
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.zaxxer.hikari;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import com.codahale.metrics.Histogram;
+import com.codahale.metrics.MetricRegistry;
+import com.codahale.metrics.Snapshot;
+
+/**
+ * THIS IS NOT ACTUALLY A UNIT TEST AND SHOULD NOT BE ANNOTATED WITH
+ * JUNIT ANNOTATIONS.  THIS IS A TEST TO MEASURE "QUEUE BARGING"
+ * BEHAVIOR.
+ *
+ * @author Brett Wooldridge
+ */
+public class BargeTest
+{
+   public static void main(String[] args) {
+      try {
+         new BargeTest().bargeTest();
+         new BargeTest().bargeTest2();
+      }
+      catch (InterruptedException e) {
+         e.printStackTrace();
+      }
+   }
+
+   private HikariDataSource ds;
+
+   public void bargeTest() throws InterruptedException {
+
+      ds = new HikariDataSource();
+      ds.setMaximumPoolSize(8);
+      ds.setConnectionTestQuery("VALUES 1");
+      ds.setDataSourceClassName("com.zaxxer.hikari.mocks.StubDataSource");
+
+      final FastWorker[] workers = new FastWorker[32];
+      for (int i = 0; i < workers.length; i++) {
+         FastWorker w = new FastWorker();
+         w.setDaemon(true);
+         workers[i] = w;
+         w.start();
+      }
+
+      Thread.sleep(1000);
+      for (final FastWorker w : workers) {
+         w.iterations = 0;
+      }
+
+      Thread.sleep(8000);
+
+      ds.close();
+
+      final MetricRegistry registry = new MetricRegistry();
+      final Histogram histogram = registry.histogram("foo");
+
+      for (final FastWorker w : workers) {
+         histogram.update(w.iterations);
+      }
+      
+      final Logger logger = LoggerFactory.getLogger(getClass());
+      final Snapshot snapshot = histogram.getSnapshot();
+      logger.info("Min: {}, Max: {}. Median: {}", snapshot.getMin(), snapshot.getMax(), (int) snapshot.getMedian());
+      logger.info("75%: {}, 95%: {}, 99%: {}", (int) snapshot.get75thPercentile(), (int)snapshot.get95thPercentile(), (int)snapshot.get99thPercentile());
+   }
+
+   public void bargeTest2() throws InterruptedException {
+      ds = new HikariDataSource();
+      ds.setMaximumPoolSize(1);
+      ds.setConnectionTestQuery("VALUES 1");
+      ds.setDataSourceClassName("com.zaxxer.hikari.mocks.StubDataSource");
+
+      final FastWorker fastWorker = new FastWorker();
+      fastWorker.setDaemon(true);
+      fastWorker.start();
+
+      final PacedWorker pacedWorker = new PacedWorker();
+      pacedWorker.setDaemon(true);
+      pacedWorker.start();
+
+      Thread.sleep(1000);
+
+      pacedWorker.iterations = 0;
+      
+      Thread.sleep(5000);
+
+      int snapshot = pacedWorker.iterations;
+
+      ds.close();
+
+      final Logger logger = LoggerFactory.getLogger(getClass());
+      logger.info("Expect paced worker connection acquisitions to be ~50.  Actual: {}", snapshot);
+
+   }
+
+   class FastWorker extends Thread {
+      volatile int iterations;
+
+      public void run() {
+         while (true) {
+            try (Connection c = ds.getConnection()) {
+               iterations++;
+               Statement statement = c.createStatement();
+               statement.execute("SOMETHING");
+            }
+            catch (SQLException e) {
+               break;
+            }
+         }
+      };
+   }
+
+   class PacedWorker extends Thread {
+      volatile int iterations;
+
+      public void run() {
+         while (true) {
+            try (Connection c = ds.getConnection()) {
+
+               // wait 100ms, but do so without sleeping ... just spin one core
+               for (final long start = System.currentTimeMillis(); System.currentTimeMillis() - start < 100;);
+
+               iterations++;
+               Statement statement = c.createStatement();
+               statement.execute("SOMETHING");
+            }
+            catch (SQLException e) {
+               break;
+            }
+         }
+      };
+   }
+}