Spring native heap dump

Question

I have a spring-boot web application which uses spring native /graalvm. Is it possible to get a heap dump of such kind of application? I tried to use: visual vm, jconsole, spring-actuator but did not succeed. These 3 options work fine for a non spring native applications. I just want to compare heap utilization of graalvm application and vanilla one.

Answer 1

You can not generate heap dump with jmap or visualVM but you can implement a code block to generate heap dump. here is example code

import java.text.DateFormat;
import java.util.Date;

public class SVMHeapDump extends Thread {
    static int i = 0;
    static int runs = 60;
    static int sleepTime = 1000;
    @Override
    public void run() {
        System.out.println(DateFormat.getDateTimeInstance().format(new Date()) + ": Thread started, it will run for " + runs + " seconds");
        while (i < runs){
            System.out.println("Sleeping for " + (runs-i) + " seconds." );
            try {
                Thread.sleep(sleepTime);
            } catch (InterruptedException ie){
                System.out.println("Sleep interrupted.");
            }
            i++;
        }
    }
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) throws InterruptedException {
        StringBuffer sb1 = new StringBuffer(100);
        sb1.append(DateFormat.getDateTimeInstance().format(new Date()));
        sb1.append(": Hello GraalVM native image developer! \nGet PID of this process: ");
        sb1.append("'ps -C svmheapdump -o pid= '\n");
        sb1.append("then send it signal: ");
        sb1.append("'kill -SIGUSR1 <pid_printed_above>' \n");
        sb1.append("to get heap dump generated into working directory.\n");
        sb1.append("Starting thread!");
        System.out.println(sb1);
        SVMHeapDump t = new SVMHeapDump();
        t.start();
        while (t.isAlive()) {
            t.join(0);
        }
        sb1 = new StringBuffer(100);
        sb1.append(DateFormat.getDateTimeInstance().format(new Date()));
        sb1.append(": Thread finished after: ");
        sb1.append(i);
        sb1.append(" iterations.");
        System.out.println(sb1);
    }
}

after you build and run that code you can send the signal with kill -SIGUSR1 100 command.

for further details please check https://www.graalvm.org/reference-manual/native-image/NativeImageHeapdump/