Don't flush buffers on every commit.

This was meant to prevent key reuse with BTPv1, it's no longer needed with BTPv2.

briar-core/src/org/briarproject/db/H2Database.java

@@ -9,7 +9,6 @@ import java.io.File;
 import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.SQLException;
-import java.sql.Statement;
 import java.util.Properties;
 
 import javax.inject.Inject;
@@ -31,9 +30,8 @@ class H2Database extends JdbcDatabase {
 		this.config = config;
 		File dir = config.getDatabaseDirectory();
 		String path = new File(dir, "db").getAbsolutePath();
-		// FIXME: Remove WRITE_DELAY=0 after implementing BTPv2?
 		url = "jdbc:h2:split:" + path + ";CIPHER=AES;MULTI_THREADED=1"
-				+ ";WRITE_DELAY=0;DB_CLOSE_ON_EXIT=false";
+				+ ";DB_CLOSE_ON_EXIT=false";
 	}
 
 	public boolean open() throws DbException {
@@ -83,10 +81,4 @@ class H2Database extends JdbcDatabase {
 		props.put("password", StringUtils.toHexString(key) + " password");
 		return DriverManager.getConnection(url, props);
 	}
-
-	@Override
-	protected void flushBuffersToDisk(Statement s) throws SQLException {
-		// FIXME: Remove this after implementing BTPv2?
-		s.execute("CHECKPOINT SYNC");
-	}
 }

briar-core/src/org/briarproject/db/JdbcDatabase.java

@@ -256,8 +256,6 @@ abstract class JdbcDatabase implements Database<Connection> {
 
 	protected abstract Connection createConnection() throws SQLException;
 
-	protected abstract void flushBuffersToDisk(Statement s) throws SQLException;
-
 	private final Lock connectionsLock = new ReentrantLock();
 	private final Condition connectionsChanged = connectionsLock.newCondition();
 
@@ -419,14 +417,9 @@ abstract class JdbcDatabase implements Database<Connection> {
 	}
 
 	public void commitTransaction(Connection txn) throws DbException {
-		Statement s = null;
 		try {
 			txn.commit();
-			s = txn.createStatement();
-			flushBuffersToDisk(s);
-			s.close();
 		} catch (SQLException e) {
-			tryToClose(s);
 			throw new DbException(e);
 		}
 		connectionsLock.lock();