Remove chatty logging of connection failures, include "last" connection failure in SQL timeout exception.

src/main/java/com/zaxxer/hikari/HikariPool.java

@@ -25,6 +25,7 @@ import java.util.TimerTask;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.atomic.AtomicReference;
 
 import javax.sql.DataSource;
 
@@ -73,7 +74,7 @@ public final class HikariPool implements HikariPoolMBean, IBagStateListener
     private final String password;
 
     private volatile boolean isShutdown;
-    private volatile long lastConnectionFailureTime;
+    private volatile AtomicReference<Throwable> lastConnectionFailure;
     private int transactionIsolation;
     private boolean isDebug;
 
@@ -97,6 +98,7 @@ public final class HikariPool implements HikariPoolMBean, IBagStateListener
         this.connectionBag = new ConcurrentBag<IHikariConnectionProxy>();
         this.connectionBag.addBagStateListener(this);
         this.isDebug = LOGGER.isDebugEnabled();
+        this.lastConnectionFailure = new AtomicReference<Throwable>();
 
         this.catalog = configuration.getCatalog();
         this.connectionCustomizer = configuration.getConnectionCustomizer();
@@ -170,7 +172,7 @@ public final class HikariPool implements HikariPoolMBean, IBagStateListener
             while (timeout > 0);
 
             logPoolState("Timeout failure ");
-            throw new SQLException(String.format("Timeout of %dms encountered waiting for connection.", configuration.getConnectionTimeout()));
+            throw new SQLException(String.format("Timeout of %dms encountered waiting for connection.", configuration.getConnectionTimeout()), lastConnectionFailure.getAndSet(null));
         }
         catch (InterruptedException e)
         {
@@ -252,6 +254,7 @@ public final class HikariPool implements HikariPoolMBean, IBagStateListener
                         sleepBackoff = (int) Math.min(1000f, ((float) sleepBackoff) * 1.5);
                         if (getThreadsAwaitingConnection() == 0)
                         {
+                            lastConnectionFailure = null;
                             break;
                         }
                         continue;
@@ -347,6 +350,7 @@ public final class HikariPool implements HikariPoolMBean, IBagStateListener
             IHikariConnectionProxy proxyConnection = ProxyFactory.getProxyConnection(this, connection, transactionIsolation, isAutoCommit, isReadOnly, catalog);
             proxyConnection.resetConnectionState();
             connectionBag.add(proxyConnection);
+            lastConnectionFailure.set(null);
             return true;
         }
         catch (Exception e)
@@ -359,12 +363,11 @@ public final class HikariPool implements HikariPoolMBean, IBagStateListener
                 PoolUtilities.quietlyCloseConnection(connection);
             }
 
-            long now = System.currentTimeMillis();
-            if (now - lastConnectionFailureTime > 1000 || isDebug)
+            lastConnectionFailure.set(e);
+            if (isDebug)
             {
                 LOGGER.warn("Connection attempt to database {} failed (not every attempt is logged): {}", configuration.getPoolName(), e.getMessage(), (isDebug ? e : null));
             }
-            lastConnectionFailureTime = now;
             return false;
         }
     }