Add validateOnHeartbeat with the ability to turn this off (typically for use with Lambda)

With Lambda we might want to turn off validateOnHeartbeat such that the heartbeat only
trims the connection pool and does not perform a background test on a connection.

Author: rbygrave

ebean-datasource-api/src/main/java/io/ebean/datasource/DataSourceBuilder.java

@@ -696,6 +696,15 @@ default DataSourceBuilder initDatabaseForPlatform(String platform) {
    */
   DataSourceBuilder shutdownOnJvmExit(boolean shutdownOnJvmExit);
 
+  /**
+   * Set whether the connection pool should be validated periodically.
+   * <p>
+   * This is enabled by default. Generally we only want to turn this
+   * off when using the pool with a Lambda function.
+   * @param validateOnHeartbeat Use false to disable heartbeat validation.
+   */
+  DataSourceBuilder validateOnHeartbeat(boolean validateOnHeartbeat);
+
   /**
    * EXPERIMENTAL feature - Set to true when using in Lambda to enable an extra
    * check to detect when the function has been restored from suspension.
@@ -753,6 +762,11 @@ interface Settings extends DataSourceBuilder {
      */
     boolean isShutdownOnJvmExit();
 
+    /**
+     * When true validate the pool when the heartbeat runs.
+     */
+    boolean isValidateOnHeartbeat();
+
     /**
      * Return the connection properties including credentials and custom parameters.
      */

ebean-datasource-api/src/main/java/io/ebean/datasource/DataSourceConfig.java

@@ -81,6 +81,7 @@ public class DataSourceConfig implements DataSourceBuilder.Settings {
   private String applicationName;
   private boolean shutdownOnJvmExit;
   private boolean useLambdaCheck;
+  private boolean validateOnHeartbeat = true;
 
   @Override
   public Settings settings() {
@@ -146,7 +147,7 @@ public DataSourceConfig copy() {
 
   @Override
   public DataSourceConfig setDefaults(DataSourceBuilder builder) {
-    DataSourceBuilder.Settings other = builder.settings();
+    Settings other = builder.settings();
     if (driver == null) {
       driver = other.driver();
     }
@@ -704,6 +705,17 @@ public DataSourceConfig shutdownOnJvmExit(boolean shutdownOnJvmExit) {
     return this;
   }
 
+  @Override
+  public boolean isValidateOnHeartbeat() {
+    return validateOnHeartbeat;
+  }
+
+  @Override
+  public DataSourceConfig validateOnHeartbeat(boolean validateOnHeartbeat) {
+    this.validateOnHeartbeat = validateOnHeartbeat;
+    return this;
+  }
+
   @Override
   public DataSourceBuilder useLambdaCheck(boolean useLambda) {
     this.useLambdaCheck = useLambda;
@@ -768,6 +780,7 @@ private void loadSettings(ConfigPropertiesHelper properties) {
     poolListener = properties.get("poolListener", poolListener);
     offline = properties.getBoolean("offline", offline);
     shutdownOnJvmExit = properties.getBoolean("shutdownOnJvmExit", shutdownOnJvmExit);
+    validateOnHeartbeat = properties.getBoolean("validateOnHeartbeat", validateOnHeartbeat);
     useLambdaCheck = properties.getBoolean("useLambdaCheck", useLambdaCheck);
 
     String isoLevel = properties.get("isolationLevel", _isolationLevel(isolationLevel));

ebean-datasource-api/src/test/java/io/ebean/datasource/DataSourceConfigTest.java

@@ -170,6 +170,7 @@ public void loadSettings() throws IOException {
     var config = new DataSourceConfig().loadSettings(props, "foo");
     assertConfigValues(config);
     assertThat(config.isShutdownOnJvmExit()).isTrue();
+    assertThat(config.isValidateOnHeartbeat()).isTrue();
     assertThat(config.useLambdaCheck()).isTrue();
   }
 
@@ -182,6 +183,7 @@ public void load_prefix() throws IOException {
     assertConfigValues(config);
     assertThat(config.isShutdownOnJvmExit()).isFalse();
     assertThat(config.useLambdaCheck()).isFalse();
+    assertThat(config.useLambdaCheck()).isFalse();
   }
 
   @Test

ebean-datasource-api/src/test/resources/example.properties

@@ -7,3 +7,4 @@ datasource.foo.applicationName=myApp
 datasource.foo.clientInfo=ClientUser=ciu;ClientHostname=cih
 datasource.foo.shutdownOnJvmExit=true
 datasource.foo.useLambdaCheck=true
+datasource.foo.validateOnHeartbeat=true

ebean-datasource/src/main/java/io/ebean/datasource/pool/ConnectionPool.java

@@ -42,7 +42,7 @@ final class ConnectionPool implements DataSourcePool {
   private final List<String> initSql;
   private final String user;
   private final String schema;
-  private final String heartbeatsql;
+  private final String heartbeatSql;
   private final int heartbeatFreqSecs;
   private final int heartbeatTimeoutSeconds;
   private final long trimPoolFreqMillis;
@@ -62,6 +62,7 @@ final class ConnectionPool implements DataSourcePool {
   private final String applicationName;
   private final DataSource source;
   private final int lambdaTrimMillis;
+  private final boolean validateOnHeartbeat;
   private long nextTrimTime;
   private long nextLambdaTrimTime;
 
@@ -111,10 +112,11 @@ final class ConnectionPool implements DataSourcePool {
     this.pstmtCacheSize = params.getPstmtCacheSize();
     this.minConnections = params.getMinConnections();
     this.maxConnections = params.getMaxConnections();
-    this.heartbeatsql = params.getHeartbeatSql();
     this.waitTimeoutMillis = params.getWaitTimeoutMillis();
     this.heartbeatFreqSecs = params.getHeartbeatFreqSecs();
     this.heartbeatTimeoutSeconds = params.getHeartbeatTimeoutSeconds();
+    this.heartbeatSql = params.getHeartbeatSql();
+    this.validateOnHeartbeat = params.isValidateOnHeartbeat();
     this.trimPoolFreqMillis = 1000L * params.getTrimPoolFreqSecs();
     this.applicationName = params.getApplicationName();
     this.clientInfo = params.getClientInfo();
@@ -374,7 +376,9 @@ private void trimIdleConnections() {
    */
   private void heartBeat() {
     trimIdleConnections();
-    testConnection();
+    if (validateOnHeartbeat) {
+      testConnection();
+    }
   }
 
   private void testConnection() {
@@ -501,15 +505,15 @@ long maxAgeMillis() {
   }
 
   private boolean testConnection(Connection conn) throws SQLException {
-    if (heartbeatsql == null) {
+    if (heartbeatSql == null) {
       return conn.isValid(heartbeatTimeoutSeconds);
     }
     // It should only error IF the DataSource is down or a network issue
     try (Statement stmt = conn.createStatement()) {
       if (heartbeatTimeoutSeconds > 0) {
         stmt.setQueryTimeout(heartbeatTimeoutSeconds);
       }
-      stmt.execute(heartbeatsql);
+      stmt.execute(heartbeatSql);
       return true;
     } finally {
       if (!conn.getAutoCommit()) {

ebean-datasource/src/main/java/io/ebean/datasource/pool/PooledConnectionQueue.java

@@ -174,7 +174,6 @@ void returnPooledConnection(PooledConnection c, boolean forceClose) {
       }
       if (forceClose || c.shouldTrimOnReturn(lastResetTime, maxAgeMillis)) {
         c.closeConnectionFully(false);
-
       } else {
         freeList.add(c);
         notEmpty.signal();

ebean-datasource/src/test/java/io/ebean/datasource/test/FactoryTest.java

@@ -53,6 +53,54 @@ void readOnly() throws Exception {
     pool.shutdown();
   }
 
+  // @Disabled
+  @Test
+  void heartbeatTrimOnly() throws Exception {
+    DataSourcePool pool = DataSourcePool.builder()
+      .name("heartbeatTrimOnly")
+      .url("jdbc:h2:mem:heartbeatTrimOnly")
+      .username("sa")
+      .password("")
+      .readOnly(true)
+      .autoCommit(true)
+      .validateOnHeartbeat(false)
+      .heartbeatFreqSecs(1)
+      .trimPoolFreqSecs(1)
+      .maxInactiveTimeSecs(3)
+      .build();
+
+    try (Connection connection = pool.getConnection()) {
+      try (PreparedStatement stmt = connection.prepareStatement("create table junk4 (acol varchar(10))")) {
+        stmt.execute();
+        connection.commit();
+      }
+    }
+    List<Connection> connections = new ArrayList<>();
+    for (int i = 0; i < 10; i++) {
+      connections.add(pool.getConnection());
+    }
+    for (Connection connection : connections) {
+      connection.close();
+    }
+    Thread.sleep(1000);
+    List<Connection> connections2 = new ArrayList<>();
+    for (int i = 0; i < 4; i++) {
+      Connection c = pool.getConnection();
+      connections2.add(c);
+    }
+    for (Connection connection : connections2) {
+      try (PreparedStatement ps = connection.prepareStatement("select * from junk4")) {
+        ps.execute();
+      }
+      connection.close();
+    }
+    for (int i = 0; i < 5; i++) {
+      Thread.sleep(1000);
+      System.out.println(".");
+    }
+    pool.shutdown();
+  }
+
   @Disabled
   @Test
   void readOnly2() throws Exception {