Network writing on remote storage is too long

[alicecaron]

Describe the current behavior

Writing a Network into a remote storage folder takes a lot more time than writing it into a local folder (x66times than in a local folder).

Describe the expected behavior

Writing a Network into a remote storage folder should takes more or less the same time than writing it into a local folder.

Describe the steps

In a Java environment (jdk17) in developpement mode, with an access to both a local and remote storage accross network.

• Create a java class with dependency on powsybl-core (current version 6.6.0-SNAPSHOT, works also in 6.5.1).

import com.powsybl.iidm.network.*;
import java.nio.file.Paths;
import java.util.Properties;

public final class WriteNetworkSandbox {

    public static void main(String[] args) {
        String filepath = "<path to network file>.xiidm";
        Network network = Network.read(new File(filepath).getPath());

        String remoteDestPath = "<path to remote folder>/output.xiidm";
        String localDestPath = "<path to local folder>/output.xiidm";

        writeNetwork(network, localDestPath);
        writeNetwork(network, remoteDestPath);
    }

    private static void writeNetwork(Network network, String destinationFile) {
        Properties properties = new Properties();
        properties.put("iidm.export.xml.version", "1.0");
        String format = "XIIDM";
        long startTime = System.currentTimeMillis();
        network.write(format, properties, Paths.get(destinationFile));
        System.out.println("Network writing duration in " + destinationFile + " : " + (System.currentTimeMillis() - startTime) + "ms");
    }

    private WriteNetworkSandbox() {
    }
}

• run this example code
• output should display duration of the 2 runs (local and remote) and remote one should be way bigger in ms than the local one when the bug is not fixed.

Output example:

Network writing duration in /local/path/output.xiidm : 1716ms
Network writing duration in /remote/path/output.xiidm : 67112ms

Environment

It is reproductible in a java with jdk17 development environment, having access to a remote folder.

Relevant Log Output

No response

Extra Information

The bug may be a regression since refactor on the Datasource part. Missing a bufferized output stream somewhere?

[olperr1]

The output stream is already buffered.
Using an unbuffered output stream takes much longer: ~ 3min on a local storage (vs ~4s), and maybe more than an hour — I stopped my test at ~40% in 30min — on a remote storage (vs ~17s).

[olperr1]

Format	Local storage	Remote storage
XIIDM	3,441ms	18,928ms
JIIDM	2,687ms	17,437ms
BIIDM	1,830ms	1,494ms