Revert "Revert "Revert "Revert "Use a LeanHit until merging is done." MERGEOK"""

14 files changed, 323 insertions, 151 deletions

diff --git a/container-search/src/main/java/com/yahoo/prelude/cluster/ClusterSearcher.java b/container-search/src/main/java/com/yahoo/prelude/cluster/ClusterSearcher.java
index e637e168030..4ffcc0a4330 100644
--- a/container-search/src/main/java/com/yahoo/prelude/cluster/ClusterSearcher.java
+++ b/container-search/src/main/java/com/yahoo/prelude/cluster/ClusterSearcher.java
@@ -184,8 +184,7 @@ public class ClusterSearcher extends Searcher {
                 : !host.equals(HostName.getLocalhost());
     }
 
-    private static ClusterParams makeClusterParams(int searchclusterIndex,
-                                                   int dispatchIndex) {
+    private static ClusterParams makeClusterParams(int searchclusterIndex, int dispatchIndex) {
         return new ClusterParams("sc" + searchclusterIndex + ".num" + dispatchIndex);
     }
 
@@ -195,11 +194,10 @@ public class ClusterSearcher extends Searcher {
                                                DocumentdbInfoConfig documentdbInfoConfig,
                                                Backend backend,
                                                Dispatcher dispatcher,
-                                               int dispatcherIndex) {
-        ClusterParams clusterParams = makeClusterParams(searchclusterIndex,
-                                                        dispatcherIndex);
-        return new FastSearcher(backend, fs4ResourcePool, dispatcher, docSumParams, clusterParams,
-                                documentdbInfoConfig);
+                                               int dispatcherIndex)
+    {
+        ClusterParams clusterParams = makeClusterParams(searchclusterIndex, dispatcherIndex);
+        return new FastSearcher(backend, fs4ResourcePool, dispatcher, docSumParams, clusterParams, documentdbInfoConfig);
     }
 
     private static VdsStreamingSearcher vdsCluster(String serverId,
diff --git a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FS4SearchInvoker.java b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FS4SearchInvoker.java
index 33715921e6d..f3867288b29 100644
--- a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FS4SearchInvoker.java
+++ b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FS4SearchInvoker.java
@@ -18,6 +18,8 @@ import com.yahoo.prelude.ConfigurationException;
 import com.yahoo.processing.request.CompoundName;
 import com.yahoo.search.Query;
 import com.yahoo.search.Result;
+import com.yahoo.search.dispatch.InvokerResult;
+import com.yahoo.search.dispatch.LeanHit;
 import com.yahoo.search.dispatch.ResponseMonitor;
 import com.yahoo.search.dispatch.SearchInvoker;
 import com.yahoo.search.dispatch.searchcluster.Node;
@@ -89,7 +91,7 @@ public class FS4SearchInvoker extends SearchInvoker implements ResponseMonitor<F
     }
 
     @Override
-    protected Result getSearchResult(Execution execution) throws IOException {
+    protected InvokerResult getSearchResult(Execution execution) throws IOException {
         if (pendingSearchError != null) {
             return errorResult(query, pendingSearchError);
         }
@@ -117,11 +119,10 @@ public class FS4SearchInvoker extends SearchInvoker implements ResponseMonitor<F
         if (query.getPresentation().getSummary() == null)
             query.getPresentation().setSummary(searcher.getDefaultDocsumClass());
 
-        Result result = new Result(query);
+        InvokerResult result = new InvokerResult(query, resultPacket.getDocumentCount());
 
-        ensureResultHitCapacity(result, resultPacket);
-        addMetaInfo(query, queryPacket.getQueryPacketData(), resultPacket, result);
-        addUnfilledHits(result, resultPacket.getDocuments(), queryPacket.getQueryPacketData());
+        addMetaInfo(query, queryPacket.getQueryPacketData(), resultPacket, result.getResult());
+        addUnfilledHits(result.getLeanHits(), resultPacket.getDocuments(), queryPacket.getQueryPacketData());
 
         return result;
     }
@@ -138,14 +139,6 @@ public class FS4SearchInvoker extends SearchInvoker implements ResponseMonitor<F
         return queryPacket;
     }
 
-    private void ensureResultHitCapacity(Result result, QueryResultPacket resultPacket) {
-        int hitCount = resultPacket.getDocumentCount();
-        if (resultPacket.getGroupData() != null) {
-            hitCount++;
-        }
-        result.hits().ensureCapacity(hitCount);
-    }
-
     private void addMetaInfo(Query query, QueryPacketData queryPacketData, QueryResultPacket resultPacket, Result result) {
         result.setTotalHitCount(resultPacket.getTotalDocumentCount());
 
@@ -192,47 +185,21 @@ public class FS4SearchInvoker extends SearchInvoker implements ResponseMonitor<F
     /**
      * Creates unfilled hits from a List of DocumentInfo instances.
      */
-    private void addUnfilledHits(Result result, List<DocumentInfo> documents, QueryPacketData queryPacketData) {
-        Query myQuery = result.getQuery();
-        Sorting sorting = myQuery.getRanking().getSorting();
+    private void addUnfilledHits(List<LeanHit> result, List<DocumentInfo> documents, QueryPacketData queryPacketData) {
         Optional<Integer> channelDistributionKey = distributionKey();
 
         for (DocumentInfo document : documents) {
-
-            try {
-                FastHit hit = new FastHit();
-                hit.setQuery(myQuery);
-                if (queryPacketData != null)
-                    hit.setQueryPacketData(queryPacketData);
-
-                hit.setFillable();
-                hit.setCached(false);
-
-                extractDocumentInfo(hit, document, sorting);
-                channelDistributionKey.ifPresent(hit::setDistributionKey);
-
-                result.hits().add(hit);
-            } catch (ConfigurationException e) {
-                log.log(LogLevel.WARNING, "Skipping hit", e);
-            } catch (Exception e) {
-                log.log(LogLevel.ERROR, "Skipping malformed hit", e);
-            }
+             byte [] sortData = document.getSortData();
+             LeanHit hit = (sortData == null)
+                     ? new LeanHit(document.getRawGlobalId(), document.getPartId(), channelDistributionKey.orElse(document.getDistributionKey()), document.getMetric())
+                     : new LeanHit(document.getRawGlobalId(), document.getPartId(), channelDistributionKey.orElse(document.getDistributionKey()), document.getSortData());
+             if (queryPacketData != null) {
+                 hit.setQueryPacketData(queryPacketData);
+             }
+             result.add(hit);
         }
     }
 
-    private void extractDocumentInfo(FastHit hit, DocumentInfo document, Sorting sorting) {
-        hit.setSource(getName());
-
-        Number rank = document.getMetric();
-
-        hit.setRelevance(new Relevance(rank.doubleValue()));
-
-        hit.setDistributionKey(document.getDistributionKey());
-        hit.setGlobalId(document.getRawGlobalId());
-        hit.setPartId(document.getPartId());
-        hit.setSortData(document.getSortData(), sorting);
-    }
-
     @Override
     public void release() {
         if (channel != null) {
diff --git a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java
index 63f3c8acc20..f7f2d08d713 100644
--- a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java
+++ b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastHit.java
@@ -75,6 +75,9 @@ public class FastHit extends Hit {
         distributionKey = 0;
     }
 
+    public FastHit(byte [] gid, double relevance, int partId, int distributionKey) {
+        this(gid, new Relevance(relevance), partId, distributionKey);
+    }
     public FastHit(byte [] gid, Relevance relevance, int partId, int distributionKey) {
         super(relevance);
         this.globalId = gid;
diff --git a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastSearcher.java b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastSearcher.java
index 6d3ae440152..6b0041a9e86 100644
--- a/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastSearcher.java
+++ b/container-search/src/main/java/com/yahoo/prelude/fastsearch/FastSearcher.java
@@ -22,6 +22,8 @@ import com.yahoo.search.grouping.GroupingRequest;
 import com.yahoo.search.grouping.request.GroupingOperation;
 import com.yahoo.search.query.Ranking;
 import com.yahoo.search.result.ErrorMessage;
+import com.yahoo.search.result.Hit;
+import com.yahoo.search.result.HitGroup;
 import com.yahoo.search.searchchain.Execution;
 
 import java.io.IOException;
@@ -141,12 +143,21 @@ public class FastSearcher extends VespaBackEndSearcher {
         QueryRewrite.rewriteSddocname(query);
     }
 
+    private void injectSource(HitGroup hits) {
+        for (Hit hit : hits.asUnorderedHits()) {
+            if (hit instanceof FastHit) {
+                hit.setSource(getName());
+            }
+        }
+    }
+
     @Override
     public Result doSearch2(Query query, Execution execution) {
         if (dispatcher.searchCluster().groupSize() == 1)
             forceSinglePassGrouping(query);
         try(SearchInvoker invoker = getSearchInvoker(query)) {
             Result result = invoker.search(query, execution);
+            injectSource(result.hits());
 
             if (query.properties().getBoolean(Ranking.RANKFEATURES, false)) {
                 // There is currently no correct choice for which
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/InterleavedSearchInvoker.java b/container-search/src/main/java/com/yahoo/search/dispatch/InterleavedSearchInvoker.java
index 388a31d1482..84e5e7d747f 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/InterleavedSearchInvoker.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/InterleavedSearchInvoker.java
@@ -93,10 +93,9 @@ public class InterleavedSearchInvoker extends SearchInvoker implements ResponseM
     }
 
     @Override
-    protected Result getSearchResult(Execution execution) throws IOException {
-        Result result = new Result(query);
-        List<Hit> merged = Collections.emptyList();
-        List<Hit> auxiliary = new ArrayList<>();
+    protected InvokerResult getSearchResult(Execution execution) throws IOException {
+        InvokerResult result = new InvokerResult(query, query.getHits());
+        List<LeanHit> merged = Collections.emptyList();
         long nextTimeout = query.getTimeLeft();
         try {
             while (!invokers.isEmpty() && nextTimeout >= 0) {
@@ -105,7 +104,7 @@ public class InterleavedSearchInvoker extends SearchInvoker implements ResponseM
                     log.fine(() -> "Search timed out with " + askedNodes + " requests made, " + answeredNodes + " responses received");
                     break;
                 } else {
-                    merged = mergeResult(result, invoker.getSearchResult(execution), merged, auxiliary);
+                    merged = mergeResult(result.getResult(), invoker.getSearchResult(execution), merged);
                     ejectInvoker(invoker);
                 }
                 nextTimeout = nextTimeout();
@@ -114,12 +113,11 @@ public class InterleavedSearchInvoker extends SearchInvoker implements ResponseM
             throw new RuntimeException("Interrupted while waiting for search results", e);
         }
 
-        insertNetworkErrors(result);
-        result.setCoverage(createCoverage());
+        insertNetworkErrors(result.getResult());
+        result.getResult().setCoverage(createCoverage());
         int needed = query.getOffset() + query.getHits();
-        result.hits().addAll(auxiliary);
         for (int index = query.getOffset(); (index < merged.size()) && (index < needed); index++) {
-            result.hits().add(merged.get(index));
+            result.getLeanHits().add(merged.get(index));
         }
         query.setOffset(0);  // Now we are all trimmed down
         return result;
@@ -191,43 +189,31 @@ public class InterleavedSearchInvoker extends SearchInvoker implements ResponseM
         return nextAdaptive;
     }
 
-    private List<Hit> mergeResult(Result result, Result partialResult, List<Hit> current, List<Hit> auxiliaryHits) {
-        collectCoverage(partialResult.getCoverage(true));
+    private List<LeanHit> mergeResult(Result result, InvokerResult partialResult, List<LeanHit> current) {
+        collectCoverage(partialResult.getResult().getCoverage(true));
 
-        result.mergeWith(partialResult);
-        List<Hit> partial = partialResult.hits().asUnorderedHits();
-        if (current.isEmpty() ) {
-            boolean hasAuxillary = false;
-            for(Hit hit : partial) {
-                if (hit.isAuxiliary()) {
-                    hasAuxillary = true;
-                    break;
-                }
+        result.mergeWith(partialResult.getResult());
+        List<Hit> partialNonLean = partialResult.getResult().hits().asUnorderedHits();
+        for(Hit hit : partialNonLean) {
+            if (hit.isAuxiliary()) {
+                result.hits().add(hit);
             }
-            if ( ! hasAuxillary)
-                return partial;
         }
+        if (current.isEmpty() ) {
+            return partialResult.getLeanHits();
+        }
+        List<LeanHit> partial = partialResult.getLeanHits();
         if (partial.isEmpty()) {
             return current;
         }
 
         int needed = query.getOffset() + query.getHits();
-        List<Hit> merged = new ArrayList<>(needed);
+        List<LeanHit> merged = new ArrayList<>(needed);
         int indexCurrent = 0;
         int indexPartial = 0;
         while (indexCurrent < current.size() && indexPartial < partial.size() && merged.size() < needed) {
-            Hit incommingHit = partial.get(indexPartial);
-            if (incommingHit.isAuxiliary()) {
-                auxiliaryHits.add(incommingHit);
-                indexPartial++;
-                continue;
-            }
-            Hit currentHit = current.get(indexCurrent);
-            if (currentHit.isAuxiliary()) {
-                auxiliaryHits.add(currentHit);
-                indexCurrent++;
-                continue;
-            }
+            LeanHit incommingHit = partial.get(indexPartial);
+            LeanHit currentHit = current.get(indexCurrent);
 
             int cmpRes = currentHit.compareTo(incommingHit);
             if (cmpRes < 0) {
@@ -242,21 +228,11 @@ public class InterleavedSearchInvoker extends SearchInvoker implements ResponseM
                 indexPartial++;
             }
         }
-        while (indexCurrent < current.size()) {
-            Hit h = current.get(indexCurrent++);
-            if (h.isAuxiliary()) {
-                auxiliaryHits.add(h);
-            } else if (merged.size() < needed) {
-                merged.add(h);
-            }
+        while ((indexCurrent < current.size()) && (merged.size() < needed)) {
+            merged.add(current.get(indexCurrent++));
         }
-        while (indexPartial < partial.size()) {
-            Hit h = partial.get(indexPartial++);
-            if (h.isAuxiliary()) {
-                auxiliaryHits.add(h);
-            } else if (merged.size() < needed) {
-                merged.add(h);
-            }
+        while ((indexPartial < partial.size()) && (merged.size() < needed)) {
+            merged.add(partial.get(indexPartial++));
         }
         return merged;
     }
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/InvokerResult.java b/container-search/src/main/java/com/yahoo/search/dispatch/InvokerResult.java
new file mode 100644
index 00000000000..cd8228624c5
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/InvokerResult.java
@@ -0,0 +1,52 @@
+package com.yahoo.search.dispatch;
+
+import com.yahoo.prelude.fastsearch.FastHit;
+import com.yahoo.search.Query;
+import com.yahoo.search.Result;
+import com.yahoo.search.query.Sorting;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+/**
+ * Wraps a Result and a flat, skinny hit list
+ */
+public class InvokerResult {
+    private final Result result;
+    private final List<LeanHit> leanHits;
+    public InvokerResult(Result result) {
+        this.result = result;
+        this.leanHits = Collections.emptyList();
+    }
+    public InvokerResult(Query query, int expectedHits) {
+        result = new Result(query);
+        leanHits = new ArrayList<>(expectedHits);
+    }
+
+    public Result getResult() {
+        return result;
+    }
+
+    public List<LeanHit> getLeanHits() {
+        return leanHits;
+    }
+    void complete() {
+        Query query = result.getQuery();
+        Sorting sorting = query.getRanking().getSorting();
+        for (LeanHit hit : leanHits) {
+            FastHit fh = new FastHit(hit.getGid(), hit.getRelevance(), hit.getPartId(), hit.getDistributionKey());
+            if (hit.hasSortData()) {
+                fh.setSortData(hit.getSortData(), sorting);
+            }
+            if (hit.getQueryPacketData() != null) {
+                fh.setQueryPacketData(hit.getQueryPacketData());
+            }
+            fh.setQuery(query);
+            fh.setFillable();
+            fh.setCached(false);
+            result.hits().add(fh);
+        }
+        leanHits.clear();
+    }
+}
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/LeanHit.java b/container-search/src/main/java/com/yahoo/search/dispatch/LeanHit.java
new file mode 100644
index 00000000000..6ec0e3f27d1
--- /dev/null
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/LeanHit.java
@@ -0,0 +1,63 @@
+package com.yahoo.search.dispatch;
+
+import com.yahoo.fs4.QueryPacketData;
+
+import java.util.Arrays;
+
+public class LeanHit implements Comparable<LeanHit> {
+    private final byte [] gid;
+    private final double relevance;
+    private final byte [] sortData;
+    private final int partId;
+    private final int distributionKey;
+    //TODO Remove when FS4 is gone
+    private QueryPacketData queryPacketData;
+    public LeanHit(byte [] gid, int partId, int distributionKey, double relevance) {
+        this.gid = gid;
+        this.relevance = relevance;
+        this.sortData = null;
+        this.partId = partId;
+        this.distributionKey = distributionKey;
+    }
+    public LeanHit(byte [] gid, int partId, int distributionKey, byte [] sortData) {
+        this.gid = gid;
+        this.relevance = Double.NEGATIVE_INFINITY;
+        this.sortData = sortData;
+        this.partId = partId;
+        this.distributionKey = distributionKey;
+    }
+    public double getRelevance() { return relevance; }
+    public byte [] getGid() { return gid; }
+    public byte [] getSortData() { return sortData; }
+    public boolean hasSortData() { return sortData != null; }
+    public int getPartId() { return partId; }
+    public int getDistributionKey() { return distributionKey; }
+
+    QueryPacketData getQueryPacketData() { return queryPacketData; }
+
+    public void setQueryPacketData(QueryPacketData queryPacketData) {
+        this.queryPacketData = queryPacketData;
+    }
+
+    @Override
+    public int compareTo(LeanHit o) {
+        int res = (sortData != null)
+                ? compareData(sortData, o.sortData)
+                : Double.compare(o.relevance, relevance);
+        return (res != 0) ? res : compareData(gid, o.gid);
+    }
+
+    private static int compareData(byte [] left, byte [] right) {
+        int i = Arrays.mismatch(left, right);
+        if (i < 0) {
+            return 0;
+        }
+        int max = Integer.min(left.length, right.length);
+        if (i >= max) {
+            return left.length - right.length;
+        }
+        int vl = (int) left[i] & 0xFF;
+        int vr = (int) right[i] & 0xFF;
+        return vl - vr;
+    }
+}
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/SearchErrorInvoker.java b/container-search/src/main/java/com/yahoo/search/dispatch/SearchErrorInvoker.java
index b1d25dddbb8..52a45dc421c 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/SearchErrorInvoker.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/SearchErrorInvoker.java
@@ -42,12 +42,12 @@ public class SearchErrorInvoker extends SearchInvoker {
     }
 
     @Override
-    protected Result getSearchResult(Execution execution) throws IOException {
+    protected InvokerResult getSearchResult(Execution execution) throws IOException {
         Result res = new Result(query, message);
         if (coverage != null) {
             res.setCoverage(coverage);
         }
-        return res;
+        return new InvokerResult(res);
     }
 
     @Override
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/SearchInvoker.java b/container-search/src/main/java/com/yahoo/search/dispatch/SearchInvoker.java
index 3bfb9089457..77b3df7c83a 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/SearchInvoker.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/SearchInvoker.java
@@ -32,14 +32,15 @@ public abstract class SearchInvoker extends CloseableInvoker {
      */
     public Result search(Query query, Execution execution) throws IOException {
         sendSearchRequest(query);
-        Result result = getSearchResult(execution);
-        setFinalStatus(result.hits().getError() == null);
-        return result;
+        InvokerResult result = getSearchResult(execution);
+        setFinalStatus(result.getResult().hits().getError() == null);
+        result.complete();
+        return result.getResult();
     }
 
     protected abstract void sendSearchRequest(Query query) throws IOException;
 
-    protected abstract Result getSearchResult(Execution execution) throws IOException;
+    protected abstract InvokerResult getSearchResult(Execution execution) throws IOException;
 
     protected void setMonitor(ResponseMonitor<SearchInvoker> monitor) {
         this.monitor = monitor;
@@ -55,12 +56,12 @@ public abstract class SearchInvoker extends CloseableInvoker {
         return node.map(Node::key);
     }
 
-    protected Result errorResult(Query query, ErrorMessage errorMessage) {
+    protected InvokerResult errorResult(Query query, ErrorMessage errorMessage) {
         Result error = new Result(query, errorMessage);
         Coverage errorCoverage = new Coverage(0, 0, 0);
         errorCoverage.setNodesTried(1);
         error.setCoverage(errorCoverage);
-        return error;
+        return new InvokerResult(error);
     }
 
 }
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java
index 6039e09bbe1..7fd41862212 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/ProtobufSerialization.java
@@ -15,6 +15,8 @@ import com.yahoo.prelude.fastsearch.GroupingListHit;
 import com.yahoo.prelude.fastsearch.VespaBackEndSearcher;
 import com.yahoo.search.Query;
 import com.yahoo.search.Result;
+import com.yahoo.search.dispatch.InvokerResult;
+import com.yahoo.search.dispatch.LeanHit;
 import com.yahoo.search.grouping.vespa.GroupingExecutor;
 import com.yahoo.search.query.Model;
 import com.yahoo.search.query.QueryTree;
@@ -22,7 +24,6 @@ import com.yahoo.search.query.Ranking;
 import com.yahoo.search.query.Sorting;
 import com.yahoo.search.query.Sorting.Order;
 import com.yahoo.search.result.Coverage;
-import com.yahoo.search.result.Relevance;
 import com.yahoo.searchlib.aggregation.Grouping;
 import com.yahoo.slime.BinaryFormat;
 import com.yahoo.vespa.objects.BufferSerializer;
@@ -180,31 +181,22 @@ public class ProtobufSerialization {
         return convertFromResult(searchResult).toByteArray();
     }
 
-    static Result deserializeToSearchResult(byte[] payload, Query query, VespaBackEndSearcher searcher, int partId, int distKey)
+    static InvokerResult deserializeToSearchResult(byte[] payload, Query query, VespaBackEndSearcher searcher, int partId, int distKey)
             throws InvalidProtocolBufferException {
         var protobuf = SearchProtocol.SearchReply.parseFrom(payload);
-        return convertToResult(query, protobuf, searcher.getDocumentDatabase(query), partId, distKey, searcher.getName());
+        return convertToResult(query, protobuf, searcher.getDocumentDatabase(query), partId, distKey);
     }
 
-    private static Result convertToResult(Query query,
-                                          SearchProtocol.SearchReply protobuf,
-                                          DocumentDatabase documentDatabase,
-                                          int partId,
-                                          int distKey,
-                                          String source) {
-        var result = new Result(query);
+    static InvokerResult convertToResult(Query query, SearchProtocol.SearchReply protobuf,
+                                                 DocumentDatabase documentDatabase, int partId, int distKey)
+    {
+        InvokerResult result = new InvokerResult(query, protobuf.getHitsCount());
 
-        result.setTotalHitCount(protobuf.getTotalHitCount());
-        result.setCoverage(convertToCoverage(protobuf));
+        result.getResult().setTotalHitCount(protobuf.getTotalHitCount());
+        result.getResult().setCoverage(convertToCoverage(protobuf));
 
-        int hitItems = protobuf.getHitsCount();
         var haveGrouping = protobuf.getGroupingBlob() != null && !protobuf.getGroupingBlob().isEmpty();
         if (haveGrouping) {
-            hitItems++;
-        }
-        result.hits().ensureCapacity(hitItems);
-
-        if (haveGrouping) {
             BufferSerializer buf = new BufferSerializer(new GrowableByteBuffer(protobuf.getGroupingBlob().asReadOnlyByteBuffer()));
             int cnt = buf.getInt(null);
             ArrayList<Grouping> list = new ArrayList<>(cnt);
@@ -215,26 +207,16 @@ public class ProtobufSerialization {
             }
             GroupingListHit hit = new GroupingListHit(list, documentDatabase.getDocsumDefinitionSet());
             hit.setQuery(query);
-            result.hits().add(hit);
+            result.getResult().hits().add(hit);
         }
 
-        var sorting = query.getRanking().getSorting();
         for (var replyHit : protobuf.getHitsList()) {
-            FastHit hit = new FastHit(replyHit.getGlobalId().toByteArray(), new Relevance(replyHit.getRelevance()), partId, distKey);
-            hit.setQuery(query);
-
-            if (!replyHit.getSortData().isEmpty()) {
-                hit.setSortData(replyHit.getSortData().toByteArray(), sorting);
-            }
-            hit.setFillable();
-            hit.setCached(false);
-            hit.setSource(source);
-
-            result.hits().add(hit);
-        }
-        if (sorting != null) {
-            result.hits().setSorted(true);
+            LeanHit hit = (replyHit.getSortData().isEmpty())
+                    ? new LeanHit(replyHit.getGlobalId().toByteArray(), partId, distKey, replyHit.getRelevance())
+                    : new LeanHit(replyHit.getGlobalId().toByteArray(), partId, distKey, replyHit.getSortData().toByteArray());
+            result.getLeanHits().add(hit);
         }
+
         var slimeTrace = protobuf.getSlimeTrace();
         if (slimeTrace != null && !slimeTrace.isEmpty()) {
             var traces = new Value.ArrayValue();
diff --git a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcSearchInvoker.java b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcSearchInvoker.java
index 9f42e794f5e..59f17501c32 100644
--- a/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcSearchInvoker.java
+++ b/container-search/src/main/java/com/yahoo/search/dispatch/rpc/RpcSearchInvoker.java
@@ -6,6 +6,7 @@ import com.yahoo.compress.Compressor;
 import com.yahoo.prelude.fastsearch.VespaBackEndSearcher;
 import com.yahoo.search.Query;
 import com.yahoo.search.Result;
+import com.yahoo.search.dispatch.InvokerResult;
 import com.yahoo.search.dispatch.SearchInvoker;
 import com.yahoo.search.dispatch.rpc.Client.ProtobufResponse;
 import com.yahoo.search.dispatch.searchcluster.Node;
@@ -60,7 +61,7 @@ public class RpcSearchInvoker extends SearchInvoker implements Client.ResponseRe
     }
 
     @Override
-    protected Result getSearchResult(Execution execution) throws IOException {
+    protected InvokerResult getSearchResult(Execution execution) throws IOException {
         long timeLeftMs = query.getTimeLeft();
         if (timeLeftMs <= 0) {
             return errorResult(query, ErrorMessage.createTimeout("Timeout while waiting for " + getName()));
diff --git a/container-search/src/test/java/com/yahoo/search/dispatch/LeanHitTest.java b/container-search/src/test/java/com/yahoo/search/dispatch/LeanHitTest.java
new file mode 100644
index 00000000000..3478038e427
--- /dev/null
+++ b/container-search/src/test/java/com/yahoo/search/dispatch/LeanHitTest.java
@@ -0,0 +1,42 @@
+package com.yahoo.search.dispatch;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class LeanHitTest {
+    byte [] gidA = {'a'};
+    byte [] gidB = {'b'};
+    byte [] gidC = {'c'};
+    private void verifyTransitiveOrdering(LeanHit a, LeanHit b, LeanHit c) {
+        assertTrue(a.compareTo(b) < 0);
+        assertTrue(b.compareTo(c) < 0);
+        assertTrue(a.compareTo(c) < 0);
+        assertTrue(b.compareTo(a) > 0);
+        assertTrue(c.compareTo(b) > 0);
+        assertTrue(c.compareTo(a) > 0);
+    }
+    @Test
+    public void testOrderingByRelevance() {
+        assertEquals(0, new LeanHit(gidA, 0, 0, 1).compareTo(new LeanHit(gidA, 0, 0, 1)));
+        verifyTransitiveOrdering(new LeanHit(gidA, 0, 0, 1),
+                new LeanHit(gidA, 0, 0, 0),
+                new LeanHit(gidA, 0, 0, -1));
+    }
+    @Test
+    public void testOrderingByGid() {
+        assertEquals(0, new LeanHit(gidA, 0, 0, 1).compareTo(new LeanHit(gidA, 0, 0, 1)));
+
+        verifyTransitiveOrdering(new LeanHit(gidA, 0, 0, 1),
+                new LeanHit(gidB, 0, 0, 1),
+                new LeanHit(gidC, 0, 0, 1));
+    }
+    @Test
+    public void testOrderingBySortData() {
+        assertEquals(0, new LeanHit(gidA, 0, 0, gidA).compareTo(new LeanHit(gidA, 0, 0, gidA)));
+        verifyTransitiveOrdering(new LeanHit(gidA, 0, 0, gidA),
+                new LeanHit(gidA, 0, 0, gidB),
+                new LeanHit(gidA, 0, 0, gidC));
+    }
+}
diff --git a/container-search/src/test/java/com/yahoo/search/dispatch/MockInvoker.java b/container-search/src/test/java/com/yahoo/search/dispatch/MockInvoker.java
index 4b2f63d6b89..2fe434d6f3f 100644
--- a/container-search/src/test/java/com/yahoo/search/dispatch/MockInvoker.java
+++ b/container-search/src/test/java/com/yahoo/search/dispatch/MockInvoker.java
@@ -1,6 +1,7 @@
 // Copyright 2019 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.search.dispatch;
 
+import com.yahoo.prelude.fastsearch.FastHit;
 import com.yahoo.search.Query;
 import com.yahoo.search.Result;
 import com.yahoo.search.dispatch.searchcluster.Node;
@@ -37,13 +38,20 @@ class MockInvoker extends SearchInvoker {
     }
 
     @Override
-    protected Result getSearchResult(Execution execution) throws IOException {
-        Result ret = new Result(query);
+    protected InvokerResult getSearchResult(Execution execution) throws IOException {
+        InvokerResult ret = new InvokerResult(query, 10);
         if (coverage != null) {
-            ret.setCoverage(coverage);
+            ret.getResult().setCoverage(coverage);
         }
         if (hits != null) {
-            ret.hits().addAll(hits);
+            for (Hit h : hits) {
+                if (h instanceof FastHit) {
+                    FastHit fh = (FastHit) h;
+                    ret.getLeanHits().add(new LeanHit(fh.getRawGlobalId(), fh.getPartId(), fh.getDistributionKey(), fh.getRelevance().getScore()));
+                } else {
+                    ret.getResult().hits().add(h);
+                }
+            }
         }
         return ret;
     }
diff --git a/container-search/src/test/java/com/yahoo/search/dispatch/rpc/ProtobufSerializationTest.java b/container-search/src/test/java/com/yahoo/search/dispatch/rpc/ProtobufSerializationTest.java
index 0b1d0d07e7a..b736ca1e6df 100644
--- a/container-search/src/test/java/com/yahoo/search/dispatch/rpc/ProtobufSerializationTest.java
+++ b/container-search/src/test/java/com/yahoo/search/dispatch/rpc/ProtobufSerializationTest.java
@@ -2,22 +2,32 @@
 
 package com.yahoo.search.dispatch.rpc;
 
+import ai.vespa.searchlib.searchprotocol.protobuf.SearchProtocol;
+import com.google.protobuf.ByteString;
 import com.yahoo.document.GlobalId;
 import com.yahoo.document.idstring.IdString;
 import com.yahoo.prelude.fastsearch.FastHit;
 import com.yahoo.search.Query;
+import com.yahoo.search.dispatch.InvokerResult;
+import com.yahoo.search.dispatch.LeanHit;
 import org.junit.Test;
 
 import java.io.IOException;
 import java.util.Collections;
+import java.util.List;
 
 import static org.hamcrest.Matchers.equalTo;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertThat;
+import static org.junit.Assert.assertTrue;
 
 /**
  * @author ollivir
  */
 public class ProtobufSerializationTest {
+    static final double DELTA = 0.000000000001;
+
     @Test
     public void testDocsumSerialization() throws IOException {
         Query q = new Query("search/?query=test&hits=10&offset=3");
@@ -29,4 +39,62 @@ public class ProtobufSerializationTest {
 
         assertThat(bytes.length, equalTo(41));
     }
+
+    SearchProtocol.SearchReply createSearchReply(int numHits, boolean useSorting) {
+        SearchProtocol.SearchReply.Builder reply = SearchProtocol.SearchReply.newBuilder();
+        reply.setTotalHitCount(7);
+
+        for (int i = 0; i < numHits; i++) {
+            SearchProtocol.Hit.Builder hit = SearchProtocol.Hit.newBuilder();
+            byte [] gid = {'a','a','a','a','a','a','a','a','a','a','a', (byte)i};
+            hit.setGlobalId(ByteString.copyFrom(gid));
+            if (useSorting) {
+                gid[0] = 'b';
+                hit.setSortData(ByteString.copyFrom(gid));
+            } else {
+                hit.setRelevance(numHits - i);
+            }
+            reply.addHits(hit);
+        }
+        return reply.build();
+    }
+    @Test
+    public void testSearhReplyDecodingWithRelevance() {
+        Query q = new Query("search/?query=test");
+        InvokerResult result = ProtobufSerialization.convertToResult(q, createSearchReply(5, false), null, 1, 2);
+        assertEquals(result.getResult().getTotalHitCount(), 7);
+        List<LeanHit> hits = result.getLeanHits();
+        assertEquals(5, hits.size());
+        double expectedRelevance = 5;
+        int hitNum = 0;
+        for (LeanHit hit : hits) {
+            assertEquals('a', hit.getGid()[0]);
+            assertEquals(hitNum, hit.getGid()[11]);
+            assertEquals(expectedRelevance--, hit.getRelevance(), DELTA);
+            assertEquals(1, hit.getPartId());
+            assertEquals(2, hit.getDistributionKey());
+            assertFalse(hit.hasSortData());
+            hitNum++;
+        }
+    }
+    @Test
+    public void testSearhReplyDecodingWithSortData() {
+        Query q = new Query("search/?query=test");
+        InvokerResult result = ProtobufSerialization.convertToResult(q, createSearchReply(5, true), null, 1, 2);
+        assertEquals(result.getResult().getTotalHitCount(), 7);
+        List<LeanHit> hits = result.getLeanHits();
+        assertEquals(5, hits.size());
+        int hitNum = 0;
+        for (LeanHit hit : hits) {
+            assertEquals('a', hit.getGid()[0]);
+            assertEquals(hitNum, hit.getGid()[11]);
+            assertEquals(Double.NEGATIVE_INFINITY, hit.getRelevance(), DELTA);
+            assertEquals(1, hit.getPartId());
+            assertEquals(2, hit.getDistributionKey());
+            assertTrue(hit.hasSortData());
+            assertEquals('b', hit.getSortData()[0]);
+            assertEquals(hitNum, hit.getSortData()[11]);
+            hitNum++;
+        }
+    }
 }