[DB] Use a single shared pool of connections to the database

src/database/DatabaseHandler.cpp

@@ -17,6 +17,9 @@
  * along with LMS.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <Wt/Dbo/FixedSqlConnectionPool>
+#include <Wt/Dbo/backend/Sqlite3>
+
 #include <Wt/Auth/Dbo/AuthInfo>
 #include <Wt/Auth/Dbo/UserDatabase>
 #include <Wt/Auth/AuthService>
@@ -72,11 +75,10 @@ Handler::getPasswordService()
 }
 
 
-Handler::Handler(boost::filesystem::path db)
-:
-_dbBackend( db.string() )
+Handler::Handler(Wt::Dbo::SqlConnectionPool& connectionPool)
 {
-	_session.setConnection(_dbBackend);
+	_session.setConnectionPool(connectionPool);
+
 	_session.mapClass<Database::Artist>("artist");
 	_session.mapClass<Database::Genre>("genre");
 	_session.mapClass<Database::Track>("track");
@@ -94,17 +96,15 @@ _dbBackend( db.string() )
 
 	try {
 	        _session.createTables();
-		_dbBackend.executeSql("CREATE INDEX artist_name_idx ON artist(name)");
-		_dbBackend.executeSql("CREATE INDEX genre_name_idx ON genre(name)");
-		_dbBackend.executeSql("CREATE INDEX release_name_idx ON release(name)");
-		_dbBackend.executeSql("CREATE INDEX track_name_idx ON track(name)");
+		_session.execute("CREATE INDEX artist_name_idx ON artist(name)");
+		_session.execute("CREATE INDEX genre_name_idx ON genre(name)");
+		_session.execute("CREATE INDEX release_name_idx ON release(name)");
+		_session.execute("CREATE INDEX track_name_idx ON track(name)");
 	}
 	catch(std::exception& e) {
 		LMS_LOG(MOD_DB, SEV_ERROR) << "Cannot create tables: " << e.what();
 	}
 
-	_dbBackend.executeSql("pragma journal_mode=WAL");
-
 	_users = new UserDatabase(_session);
 }
 
@@ -149,5 +149,16 @@ Handler::getUser(const Wt::Auth::User& authUser)
 	return user;
 }
 
+Wt::Dbo::SqlConnectionPool*
+Handler::createConnectionPool(boost::filesystem::path p)
+{
+	Wt::Dbo::backend::Sqlite3 *connection = new Wt::Dbo::backend::Sqlite3(p.string());
+
+	connection->executeSql("pragma journal_mode=WAL");
+
+	//  connection->setProperty("show-queries", "true");
+	return new Wt::Dbo::FixedSqlConnectionPool(connection, 10);
+}
+
 
 } // namespace Database

src/database/DatabaseHandler.hpp

@@ -23,7 +23,8 @@
 #include <boost/filesystem.hpp>
 
 #include <Wt/Dbo/Dbo>
-#include <Wt/Dbo/backend/Sqlite3>
+#include <Wt/Dbo/SqlConnectionPool>
+
 #include <Wt/Auth/Dbo/UserDatabase>
 #include <Wt/Auth/Login>
 #include <Wt/Auth/PasswordService>
@@ -39,7 +40,7 @@ class Handler
 {
 	public:
 
-		Handler(boost::filesystem::path db);
+		Handler(Wt::Dbo::SqlConnectionPool& connectionPool);
 		~Handler();
 
 		Wt::Dbo::Session& getSession() { return _session; }
@@ -56,12 +57,11 @@ class Handler
 		static const Wt::Auth::AuthService& getAuthService();
 		static const Wt::Auth::PasswordService& getPasswordService();
 
+		static Wt::Dbo::SqlConnectionPool*	createConnectionPool(boost::filesystem::path db);
 
 	private:
 
-		Wt::Dbo::backend::Sqlite3	_dbBackend;
 		Wt::Dbo::Session		_session;
-
 		UserDatabase*			_users;
 		Wt::Auth::Login 		_login;