mat

安装

下载
- https://www.eclipse.org/mat/

超大Dump文件分析

步骤

jmap 导出堆栈

$ jmap -dump:live,format=b,file=<file-name> <pid>

运行

$ ./ParseHeapDump.sh <file-name> org.eclipse.mat.api:suspects org.eclipse.mat.api:overview org.eclipse.mat.api:top_components

编写代码查看堆栈信息

import org.eclipse.mat.SnapshotException;
import org.eclipse.mat.parser.model.PrimitiveArrayImpl;
import org.eclipse.mat.snapshot.ISnapshot;
import org.eclipse.mat.parser.internal.SnapshotFactory;
import org.eclipse.mat.snapshot.model.IClass;
import org.eclipse.mat.snapshot.model.IObject;
import org.eclipse.mat.util.ConsoleProgressListener;
import org.eclipse.mat.util.IProgressListener;
import java.io.File;
import java.io.IOException;
import java.util.Collection;
import java.util.HashMap;
public class Main {
    public static void main(String[] args) throws SnapshotException, IOException {
            String arg = args[args.length - 1];
        String fileName = arg;
        IProgressListener listener = new ConsoleProgressListener(System.out);
        SnapshotFactory sf = new SnapshotFactory();
        ISnapshot snapshot = sf.openSnapshot(new File(fileName),
                new HashMap<String, String>(), listener);
        System.out.println(snapshot.getSnapshotInfo());
        System.out.println();
        String[] classNames = {"java.lang.String"};
        for (String name : classNames) {
            Collection<IClass> classes = snapshot.getClassesByName(name, false);
            if (classes == null || classes.isEmpty()) {
                System.out.println(String.format("Cannot find class %s in heap dump", name));
                continue;
            }
            assert classes.size() == 1;
            IClass clazz = classes.iterator().next();
            int[] objIds = clazz.getObjectIds();
            long minRetainedSize = snapshot.getMinRetainedSize(objIds, listener);
            System.out.println(String.format("%s instances = %d, retained size >= %d", clazz.getName(), objIds.length, minRetainedSize));
            for (int i = 0; i < objIds.length; i++) {
                IObject str = snapshot.getObject(objIds[i]);
                String address = Long.toHexString(snapshot.mapIdToAddress(objIds[i]));
                PrimitiveArrayImpl chars = (PrimitiveArrayImpl) str.resolveValue("value");
                String value = new String((char[]) chars.getValueArray());
                System.out.println(String.format("id=%d, address=%s, value=%s", objIds[i], address, value));
            }
        }
    }
}

设置使用内存

打开 MemoryAnalyzer.ini
修改 -Xmx1024m

参考

最后更新于4年前

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