public void closeInnerConnection() {
        final Connection innerConnection = this.innerConnection;
        if (innerConnection == null) {
            return;
        }

        try {
            innerConnection.close();
        } catch (SQLException ignored) {
            // ignore
        } finally {
            this.innerConnection = null;
        }
    }
for test only
WARNING Not thread safe
agent-module/plugins-test-module/plugins-it-utils-jdbc/src/main/java/com/navercorp/pinpoint/it/plugin/utils/jdbc/template/TransactionDataSource.java