diff --git a/marginalia_nu/build.gradle b/marginalia_nu/build.gradle
index 1be5b722..7e0884db 100644
--- a/marginalia_nu/build.gradle
+++ b/marginalia_nu/build.gradle
@@ -158,6 +158,8 @@ dependencies {
     jmh 'org.openjdk.jmh:jmh-core:1.35'
     jmh 'org.openjdk.jmh:jmh-generator-annprocess:1.35'
 
+    implementation 'net.agkn:hll:1.6.0'
+
 }
 
 configurations {
diff --git a/marginalia_nu/src/main/java/nu/marginalia/wmsa/configuration/ServiceDescriptor.java b/marginalia_nu/src/main/java/nu/marginalia/wmsa/configuration/ServiceDescriptor.java
index 1a8c7f8d..4fc59afe 100644
--- a/marginalia_nu/src/main/java/nu/marginalia/wmsa/configuration/ServiceDescriptor.java
+++ b/marginalia_nu/src/main/java/nu/marginalia/wmsa/configuration/ServiceDescriptor.java
@@ -82,7 +82,8 @@ public enum ServiceDescriptor {
                 new ConvertCommand(),
                 new LoadCommand(),
                 new ReindexCommand(),
-                new VersionCommand()
+                new VersionCommand(),
+                new IndexDataDumpCommand()
         ).collect(Collectors.toMap(c -> c.name, c -> c));
 
         if(args.length > 0) {
diff --git a/marginalia_nu/src/main/java/nu/marginalia/wmsa/configuration/command/IndexDataDumpCommand.java b/marginalia_nu/src/main/java/nu/marginalia/wmsa/configuration/command/IndexDataDumpCommand.java
new file mode 100644
index 00000000..75ea02c7
--- /dev/null
+++ b/marginalia_nu/src/main/java/nu/marginalia/wmsa/configuration/command/IndexDataDumpCommand.java
@@ -0,0 +1,24 @@
+package nu.marginalia.wmsa.configuration.command;
+
+import lombok.SneakyThrows;
+import nu.marginalia.wmsa.edge.tools.IndexJournalDumpTool;
+
+import java.util.Arrays;
+
+public class IndexDataDumpCommand extends Command {
+    public IndexDataDumpCommand() {
+        super("index-dump");
+    }
+
+    @SneakyThrows
+    @Override
+    public void execute(String... args) {
+        if (args.length < 1) {
+            System.err.println("Usage: index-dump [sub-command] index.dat");
+            System.exit(255);
+        }
+
+        String[] args2 = Arrays.copyOfRange(args, 1, args.length);
+        IndexJournalDumpTool.main(args2);
+    }
+}
diff --git a/marginalia_nu/src/main/java/nu/marginalia/wmsa/edge/tools/IndexJournalDumpTool.java b/marginalia_nu/src/main/java/nu/marginalia/wmsa/edge/tools/IndexJournalDumpTool.java
index eebabaa2..dd61ea28 100644
--- a/marginalia_nu/src/main/java/nu/marginalia/wmsa/edge/tools/IndexJournalDumpTool.java
+++ b/marginalia_nu/src/main/java/nu/marginalia/wmsa/edge/tools/IndexJournalDumpTool.java
@@ -1,5 +1,7 @@
 package nu.marginalia.wmsa.edge.tools;
 
+import com.google.common.hash.Hashing;
+import net.agkn.hll.HLL;
 import nu.marginalia.util.multimap.MultimapFileLong;
 import nu.marginalia.wmsa.edge.index.journal.SearchIndexJournalReader;
 
@@ -8,7 +10,36 @@ import java.nio.file.Path;
 
 public class IndexJournalDumpTool {
     public static void main(String... args) throws IOException {
-        var reader = new SearchIndexJournalReader(MultimapFileLong.forReading(Path.of(args[0])));
+        final String operation = args.length > 0 ? args[0] : "help";
+
+        switch (operation) {
+            case "dump":
+                dump(Path.of(args[1]));
+                break;
+            case "cardinality":
+                cardinality(Path.of(args[1]));
+                break;
+            default:
+                System.err.println("Usage: dump|cardinality index-file.dat");
+                break;
+        }
+
+    }
+
+    private static void cardinality(Path file) throws IOException {
+        var reader = new SearchIndexJournalReader(MultimapFileLong.forReading(file));
+        HLL hyperloglog = new HLL(30, 1);
+        var hashFunction = Hashing.murmur3_128();
+
+        for (var entry : reader) {
+            hyperloglog.addRaw(hashFunction.hashLong(entry.docId()).padToLong());
+        }
+
+        System.out.println(hyperloglog.cardinality());
+    }
+
+    private static void dump(Path file) throws IOException {
+        var reader = new SearchIndexJournalReader(MultimapFileLong.forReading(file));
         for (var entry : reader) {
             System.out.printf("%s\t%010d\t%06d:%08d\n", entry.block(), entry.docId(), entry.domainId(), entry.urlId());
         }
diff --git a/marginalia_nu/src/test/java/nu/marginalia/wmsa/edge/search/query/QueryVariantsTest.java b/marginalia_nu/src/test/java/nu/marginalia/wmsa/edge/search/query/QueryVariantsTest.java
index 597341bc..79946d82 100644
--- a/marginalia_nu/src/test/java/nu/marginalia/wmsa/edge/search/query/QueryVariantsTest.java
+++ b/marginalia_nu/src/test/java/nu/marginalia/wmsa/edge/search/query/QueryVariantsTest.java
@@ -36,6 +36,7 @@ class QueryVariantsTest {
     @Test
     void getQueryVariants() {
         System.out.println(se.extractSentence("we are alone"));
+        testCase("inside job reviews");
         testCase("DOS");
         testCase("dos");
         testCase("we are alone");