Unit test for issue #451

src/test/java/com/zaxxer/hikari/pool/AddConnectionRaceConditionTest.java

@@ -0,0 +1,83 @@
+package com.zaxxer.hikari.pool;
+
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Future;
+
+import org.junit.Test;
+
+import com.zaxxer.hikari.HikariConfig;
+import com.zaxxer.hikari.HikariDataSource;
+
+/**
+ * @author Matthew Tambara (matthew.tambara@liferay.com)
+ */
+public class AddConnectionRaceConditionTest
+{
+   private HikariPool _hikariPool;
+
+   // @Test
+   public void testRaceCondition() throws Exception
+   {
+      HikariConfig config = new HikariConfig();
+      config.setMinimumIdle(0);
+      config.setMaximumPoolSize(10);
+      config.setInitializationFailFast(false);
+      config.setDataSourceClassName("com.zaxxer.hikari.mocks.StubDataSource");
+
+      // Initialize HikariPool with no initial connections and room to grow
+      try (final HikariDataSource ds = new HikariDataSource(config)) {
+         _hikariPool = TestElf.getPool(ds);
+
+         ExecutorService threadPool = Executors.newFixedThreadPool(2);
+         for (int i = 0; i < 100000; i++) {
+            Future<Exception> submit1 = threadPool.submit(new Callable<Exception>() {
+               /** {@inheritDoc} */
+               @Override
+               public Exception call() throws Exception
+               {
+                  Connection c2;
+                  try {
+                     c2 = _hikariPool.getConnection(5000);
+                     ds.evictConnection(c2);
+                  }
+                  catch (SQLException e) {
+                     return e;
+                  }
+                  return null;
+               }
+            });
+
+            Future<Exception> submit2 = threadPool.submit(new Callable<Exception>() {
+               /** {@inheritDoc} */
+               @Override
+               public Exception call() throws Exception
+               {
+                  Connection c2;
+                  try {
+                     c2 = _hikariPool.getConnection(5000);
+                     ds.evictConnection(c2);
+                  }
+                  catch (SQLException e) {
+                     return e;
+                  }
+                  return null;
+               }
+            });
+
+            if (submit1.get() != null) {
+               throw submit1.get();
+            }
+            if (submit2.get() != null) {
+               throw submit2.get();
+            }
+         }
+      }
+      catch (Exception e) {
+         throw e;
+      }
+   }
+}

src/test/java/com/zaxxer/hikari/pool/TestConnectionTimeoutRetry.java

@@ -1,5 +1,7 @@
 package com.zaxxer.hikari.pool;
 
+import java.io.ByteArrayOutputStream;
+import java.io.PrintStream;
 import java.sql.Connection;
 import java.sql.SQLException;
 import java.util.concurrent.Executors;
@@ -9,6 +11,7 @@ import java.util.concurrent.TimeUnit;
 import org.junit.Assert;
 import org.junit.Test;
 
+import com.sun.media.jfxmedia.logging.Logger;
 import com.zaxxer.hikari.HikariConfig;
 import com.zaxxer.hikari.HikariDataSource;
 import com.zaxxer.hikari.mocks.StubConnection;
@@ -225,6 +228,12 @@ public class TestConnectionTimeoutRetry
 
       System.setProperty("com.zaxxer.hikari.housekeeping.periodMs", "400");
 
+      ByteArrayOutputStream baos = new ByteArrayOutputStream();
+      PrintStream ps = new PrintStream(baos, true);
+      TestElf.setSlf4jTargetStream(HikariPool.class, ps);
+      TestElf.setSlf4jLogLevel(HikariPool.class, Logger.DEBUG);
+
+      boolean success = false;
       try (HikariDataSource ds = new HikariDataSource(config)) {
          Connection connection1 = ds.getConnection();
          Connection connection2 = ds.getConnection();
@@ -234,7 +243,7 @@ public class TestConnectionTimeoutRetry
          Connection connection6 = ds.getConnection();
          Connection connection7 = ds.getConnection();
 
-         Thread.sleep(2500);
+         Thread.sleep(900);
 
          Assert.assertSame("Total connections not as expected", 10, TestElf.getPool(ds).getTotalConnections());
          Assert.assertSame("Idle connections not as expected", 3, TestElf.getPool(ds).getIdleConnections());
@@ -249,9 +258,14 @@ public class TestConnectionTimeoutRetry
 
          Assert.assertSame("Totals connections not as expected", 10, TestElf.getPool(ds).getTotalConnections());
          Assert.assertSame("Idle connections not as expected", 10, TestElf.getPool(ds).getIdleConnections());
+         success = true;
       }
       finally {
+         TestElf.setSlf4jLogLevel(HikariPool.class, Logger.INFO);
          System.getProperties().remove("com.zaxxer.hikari.housekeeping.periodMs");
+         if (!success) {
+            System.err.println(new String(baos.toByteArray()));
+         }
       }
    }
 }