diff --git a/code/api/index-api/src/main/java/nu/marginalia/index/client/model/results/SearchResultItem.java b/code/api/index-api/src/main/java/nu/marginalia/index/client/model/results/SearchResultItem.java
index 23b1f14a..19f879ca 100644
--- a/code/api/index-api/src/main/java/nu/marginalia/index/client/model/results/SearchResultItem.java
+++ b/code/api/index-api/src/main/java/nu/marginalia/index/client/model/results/SearchResultItem.java
@@ -11,7 +11,8 @@ import java.util.List;
 /** Represents a document matching a search query */
 @AllArgsConstructor @Getter
 public class SearchResultItem implements Comparable<SearchResultItem> {
-    /** Encoded ID that contains both the URL id and its ranking */
+    /** Encoded ID that contains both the URL id and its ranking.  This is
+     * probably not what you want, use getDocumentId() instead */
     public final long combinedId;
 
     /** How did the subqueries match against the document ? */
@@ -20,8 +21,8 @@ public class SearchResultItem implements Comparable<SearchResultItem> {
     /** How many other potential results existed in the same domain */
     public int resultsFromDomain;
 
-    public SearchResultItem(long val) {
-        this.combinedId = val;
+    public SearchResultItem(long combinedId) {
+        this.combinedId = combinedId;
         this.keywordScores = new ArrayList<>(16);
     }
 
@@ -66,16 +67,6 @@ public class SearchResultItem implements Comparable<SearchResultItem> {
         return false;
     }
 
-    public long deduplicationKey() {
-        final int domainId = getDomainId();
-
-        if (domainId == Integer.MAX_VALUE || domainId == Integer.MIN_VALUE) {
-            return 0;
-        }
-
-        return domainId;
-    }
-
     @Override
     public int compareTo(@NotNull SearchResultItem o) {
         // this looks like a bug, but we actually want this in a reversed order
diff --git a/code/services-core/index-service/src/main/java/nu/marginalia/index/results/IndexResultDomainDeduplicator.java b/code/services-core/index-service/src/main/java/nu/marginalia/index/results/IndexResultDomainDeduplicator.java
index 8dbf740f..4c29886a 100644
--- a/code/services-core/index-service/src/main/java/nu/marginalia/index/results/IndexResultDomainDeduplicator.java
+++ b/code/services-core/index-service/src/main/java/nu/marginalia/index/results/IndexResultDomainDeduplicator.java
@@ -5,7 +5,7 @@ import gnu.trove.map.hash.TLongIntHashMap;
 import nu.marginalia.index.client.model.results.SearchResultItem;
 
 public class IndexResultDomainDeduplicator {
-    final TLongIntMap resultsByRankingId = CachedObjects.getMap();
+    final TLongIntMap resultsByDomainId = CachedObjects.getMap();
     final int limitByDomain;
 
     public IndexResultDomainDeduplicator(int limitByDomain) {
@@ -13,19 +13,15 @@ public class IndexResultDomainDeduplicator {
     }
 
     public boolean test(SearchResultItem item) {
-        final long key = item.deduplicationKey();
-        if (key == 0)
-            return true;
+        final long key = item.getDomainId();
 
-        return resultsByRankingId.adjustOrPutValue(key, 1, 1) <= limitByDomain;
+        return resultsByDomainId.adjustOrPutValue(key, 1, 1) <= limitByDomain;
     }
 
     public int getCount(SearchResultItem item) {
-        final long key = item.deduplicationKey();
-        if (key == 0)
-            return 1;
+        final long key = item.getDomainId();
 
-        return resultsByRankingId.get(key);
+        return resultsByDomainId.get(key);
     }
 
     private static class CachedObjects {
@@ -38,7 +34,14 @@ public class IndexResultDomainDeduplicator {
             ret.clear();
             return ret;
         }
+
+        public static void clear() {
+            mapCache.remove();
+        }
     }
 
+    static void clearCachedObjects() {
+        CachedObjects.clear();
+    }
 }
 
diff --git a/code/services-core/index-service/src/test/java/nu/marginalia/index/results/IndexResultDomainDeduplicatorTest.java b/code/services-core/index-service/src/test/java/nu/marginalia/index/results/IndexResultDomainDeduplicatorTest.java
new file mode 100644
index 00000000..a2960a67
--- /dev/null
+++ b/code/services-core/index-service/src/test/java/nu/marginalia/index/results/IndexResultDomainDeduplicatorTest.java
@@ -0,0 +1,35 @@
+package nu.marginalia.index.results;
+
+import nu.marginalia.index.client.model.results.SearchResultItem;
+import nu.marginalia.model.id.UrlIdCodec;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class IndexResultDomainDeduplicatorTest {
+
+    @AfterEach
+    public void clear() {
+        IndexResultDomainDeduplicator.clearCachedObjects();
+    }
+
+    @Test
+    public void testDeduplicator() {
+
+        IndexResultDomainDeduplicator deduplicator = new IndexResultDomainDeduplicator(3);
+
+        assertTrue(deduplicator.test(forId(3, 0)));
+        assertTrue(deduplicator.test(forId(3, 1)));
+        assertTrue(deduplicator.test(forId(3, 2)));
+        assertFalse(deduplicator.test(forId(3, 3)));
+        assertFalse(deduplicator.test(forId(3, 4)));
+
+        assertEquals(5, deduplicator.getCount(forId(3, 3)));
+    }
+
+    SearchResultItem forId(int domain, int ordinal) {
+        return new SearchResultItem(UrlIdCodec.encodeId(domain, ordinal));
+    }
+
+}
\ No newline at end of file