diff --git a/java/src/main/java/org/softwareheritage/graph/experiments/topology/SubdatasetSizeFunction.java b/java/src/main/java/org/softwareheritage/graph/experiments/topology/SubdatasetSizeFunction.java
new file mode 100644
index 0000000..b84cabe
--- /dev/null
+++ b/java/src/main/java/org/softwareheritage/graph/experiments/topology/SubdatasetSizeFunction.java
@@ -0,0 +1,88 @@
+package org.softwareheritage.graph.experiments.topology;
+
+import com.google.common.primitives.Longs;
+import com.martiansoftware.jsap.*;
+import it.unimi.dsi.Util;
+import it.unimi.dsi.big.webgraph.LazyLongIterator;
+import it.unimi.dsi.bits.LongArrayBitVector;
+import it.unimi.dsi.fastutil.Arrays;
+import it.unimi.dsi.fastutil.BigArrays;
+import it.unimi.dsi.fastutil.longs.LongBigArrays;
+import it.unimi.dsi.io.ByteDiskQueue;
+import it.unimi.dsi.logging.ProgressLogger;
+import it.unimi.dsi.util.XoRoShiRo128PlusRandom;
+import org.softwareheritage.graph.Graph;
+import org.softwareheritage.graph.Node;
+import org.softwareheritage.graph.experiments.forks.ForkCC;
+
+import java.io.*;
+
+public class SubdatasetSizeFunction {
+
+	private SubdatasetSizeFunction() {}
+
+	public static void run(final Graph graph) throws IOException {
+		final ProgressLogger pl = new ProgressLogger();
+		pl.itemsName = "nodes";
+		pl.expectedUpdates = graph.numNodes();
+
+		long n = graph.numNodes();
+		LongArrayBitVector visited = LongArrayBitVector.ofLength(n);
+
+		int bufferSize = (int) Math.min(Arrays.MAX_ARRAY_SIZE & ~0x7, 8L * n);
+		final File queueFile = File.createTempFile(ForkCC.class.getSimpleName(), "queue");
+		final ByteDiskQueue queue = ByteDiskQueue.createNew(queueFile, bufferSize, true);
+		final byte[] byteBuf = new byte[Long.BYTES];
+
+		long[][] randomPerm = Util.identity(graph.numNodes());
+		LongBigArrays.shuffle(randomPerm, new XoRoShiRo128PlusRandom());
+
+		long visitedSize = 0;
+		pl.start("Running traversal starting from origins...");
+		for (long j = 0; j < n; ++j) {
+		    long i = BigArrays.get(randomPerm, j);
+			if (visited.getBoolean(i) || graph.getNodeType(i) != Node.Type.ORI) {
+				continue;
+			}
+			queue.enqueue(Longs.toByteArray(i));
+			visited.set(i);
+
+			while (!queue.isEmpty()) {
+				queue.dequeue(byteBuf);
+				final long currentNode = Longs.fromByteArray(byteBuf);
+
+				visitedSize++;
+
+				final LazyLongIterator iterator = graph.successors(currentNode);
+				long succ;
+				while ((succ = iterator.nextLong()) != -1) {
+					if (visited.getBoolean(succ))
+						continue;
+					visited.set(succ);
+					queue.enqueue(Longs.toByteArray(succ));
+				}
+
+				pl.update();
+			}
+
+			System.out.println(visitedSize);
+		}
+		pl.done();
+	}
+
+	static public void main(final String[] arg) throws IllegalArgumentException, SecurityException, JSAPException, IOException {
+		final SimpleJSAP jsap = new SimpleJSAP(SubdatasetSizeFunction.class.getName(), "Computes in and out degrees of the given SWHGraph",
+				new Parameter[] {
+						new UnflaggedOption("basename", JSAP.STRING_PARSER, JSAP.NO_DEFAULT, JSAP.REQUIRED, JSAP.NOT_GREEDY, "The basename of the graph."),
+					}
+				);
+
+		final JSAPResult jsapResult = jsap.parse(arg);
+		if (jsap.messagePrinted()) System.exit(1);
+
+		final String basename = jsapResult.getString("basename");
+
+		Graph graph = new Graph(basename);
+		run(graph);
+	}
+}