Merge pull request #12401 from vespa-engine/arnej/extend-nns-item

Arnej/extend nns item.

15 files changed, 87 insertions, 57 deletions

diff --git a/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp b/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp
index 24be21f65ec..47728c9785c 100644
--- a/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp
+++ b/searchlib/src/tests/attribute/searchable/attributeblueprint_test.cpp
@@ -295,7 +295,7 @@ public:
         request_ctx.set_query_tensor("query_tensor", tensor_spec);
     }
     Blueprint::UP create_blueprint() {
-        query::NearestNeighborTerm term("query_tensor", attr_name, 0, Weight(0), 7);
+        query::NearestNeighborTerm term("query_tensor", attr_name, 0, Weight(0), 7, true, 33);
         return source.createBlueprint(request_ctx, FieldSpec(attr_name, 0, 0), term);
     }
 };
diff --git a/searchlib/src/tests/query/query_visitor_test.cpp b/searchlib/src/tests/query/query_visitor_test.cpp
index 39e381c0942..edbc29be784 100644
--- a/searchlib/src/tests/query/query_visitor_test.cpp
+++ b/searchlib/src/tests/query/query_visitor_test.cpp
@@ -99,7 +99,7 @@ void Test::requireThatAllNodesCanBeVisited() {
     checkVisit<SuffixTerm>(new SimpleSuffixTerm("t", "field", 0, Weight(0)));
     checkVisit<PredicateQuery>(new SimplePredicateQuery(PredicateQueryTerm::UP(), "field", 0, Weight(0)));
     checkVisit<RegExpTerm>(new SimpleRegExpTerm("t", "field", 0, Weight(0)));
-    checkVisit<NearestNeighborTerm>(new SimpleNearestNeighborTerm("query_tensor", "doc_tensor", 0, Weight(0), 123));
+    checkVisit<NearestNeighborTerm>(new SimpleNearestNeighborTerm("query_tensor", "doc_tensor", 0, Weight(0), 123, true, 321));
 }
 
 }  // namespace
diff --git a/searchlib/src/tests/query/querybuilder_test.cpp b/searchlib/src/tests/query/querybuilder_test.cpp
index 7f496b3493c..8560cb0e091 100644
--- a/searchlib/src/tests/query/querybuilder_test.cpp
+++ b/searchlib/src/tests/query/querybuilder_test.cpp
@@ -111,7 +111,7 @@ Node::UP createQueryTree() {
             builder.addStringTerm(str[5], view[5], id[5], weight[6]);
             builder.addStringTerm(str[6], view[6], id[6], weight[7]);
         }
-        builder.add_nearest_neighbor_term("query_tensor", "doc_tensor", id[3], weight[5], 7);
+        builder.add_nearest_neighbor_term("query_tensor", "doc_tensor", id[3], weight[5], 7, true, 33);
     }
     Node::UP node = builder.build();
     ASSERT_TRUE(node.get());
@@ -395,8 +395,9 @@ struct MyRegExpTerm : RegExpTerm {
 };
 struct MyNearestNeighborTerm : NearestNeighborTerm {
     MyNearestNeighborTerm(vespalib::stringref query_tensor_name, vespalib::stringref field_name,
-                          int32_t i, Weight w, uint32_t target_num_hits)
-        : NearestNeighborTerm(query_tensor_name, field_name, i, w, target_num_hits)
+                          int32_t i, Weight w, uint32_t target_num_hits,
+                          bool allow_approximate, uint32_t explore_additional_hits)
+        : NearestNeighborTerm(query_tensor_name, field_name, i, w, target_num_hits, allow_approximate, explore_additional_hits)
     {}
 };
 
diff --git a/searchlib/src/vespa/searchlib/attribute/attribute_blueprint_factory.cpp b/searchlib/src/vespa/searchlib/attribute/attribute_blueprint_factory.cpp
index 8595b0eff7f..9af05059bef 100644
--- a/searchlib/src/vespa/searchlib/attribute/attribute_blueprint_factory.cpp
+++ b/searchlib/src/vespa/searchlib/attribute/attribute_blueprint_factory.cpp
@@ -646,7 +646,9 @@ public:
         query_tensor.release();
         setResult(std::make_unique<queryeval::NearestNeighborBlueprint>(_field, *dense_attr_tensor,
                                                                         std::move(dense_query_tensor_up),
-                                                                        n.get_target_num_hits()));
+                                                                        n.get_target_num_hits(),
+                                                                        n.get_allow_approximate(),
+                                                                        n.get_explore_additional_hits()));
     }
 };
 
diff --git a/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp b/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp
index 70a3097ae05..c42cf8fc370 100644
--- a/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp
+++ b/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.cpp
@@ -21,9 +21,11 @@ SimpleQueryStackDumpIterator::SimpleQueryStackDumpIterator(vespalib::stringref b
     _currUniqueId(0),
     _currFlags(0),
     _currArity(0),
-    _currArg1(0),
-    _currArg2(0),
-    _currArg3(0),
+    _extraIntArg1(0),
+    _extraIntArg2(0),
+    _extraIntArg3(0),
+    _extraDoubleArg4(0),
+    _extraDoubleArg5(0),
     _predicate_query_term(),
     _curr_index_name(),
     _curr_term(),
@@ -138,7 +140,6 @@ SimpleQueryStackDumpIterator::next()
     case ParseItem::ITEM_ANY:
         try {
             _currArity = readCompressedPositiveInt(p);
-            _currArg1 = 0;
             _curr_index_name = vespalib::stringref();
             _curr_term = vespalib::stringref();
         } catch (...) {
@@ -150,7 +151,7 @@ SimpleQueryStackDumpIterator::next()
     case ParseItem::ITEM_ONEAR:
         try {
             _currArity = readCompressedPositiveInt(p);
-            _currArg1 = readCompressedPositiveInt(p);
+            _extraIntArg1 = readCompressedPositiveInt(p);
             _curr_index_name = vespalib::stringref();
             _curr_term = vespalib::stringref();
         } catch (...) {
@@ -161,7 +162,7 @@ SimpleQueryStackDumpIterator::next()
     case ParseItem::ITEM_WEAK_AND:
         try {
             _currArity = readCompressedPositiveInt(p);
-            _currArg1 = readCompressedPositiveInt(p);
+            _extraIntArg1 = readCompressedPositiveInt(p); // targetNumHits
             _curr_index_name = read_stringref(p);
             _curr_term = vespalib::stringref();
         } catch (...) {
@@ -171,7 +172,6 @@ SimpleQueryStackDumpIterator::next()
     case ParseItem::ITEM_SAME_ELEMENT:
         try {
             _currArity = readCompressedPositiveInt(p);
-            _currArg1 = 0;
             _curr_index_name = read_stringref(p);
             _curr_term = vespalib::stringref();
         } catch (...) {
@@ -182,7 +182,6 @@ SimpleQueryStackDumpIterator::next()
     case ParseItem::ITEM_PURE_WEIGHTED_STRING:
         try {
             _curr_term = read_stringref(p);
-            _currArg1 = 0;
             _currArity = 0;
         } catch (...) {
             return false;
@@ -196,7 +195,6 @@ SimpleQueryStackDumpIterator::next()
         p += sizeof(int64_t);
         if (p > _bufEnd) return false;
 
-        _currArg1 = 0;
         _currArity = 0;
         break;
     case ParseItem::ITEM_WORD_ALTERNATIVES:
@@ -218,7 +216,6 @@ SimpleQueryStackDumpIterator::next()
         try {
             _curr_index_name = read_stringref(p);
             _curr_term = read_stringref(p);
-            _currArg1 = 0;
             _currArity = 0;
         } catch (...) {
             return false;
@@ -258,11 +255,9 @@ SimpleQueryStackDumpIterator::next()
             _currArity = readCompressedPositiveInt(p);
             _curr_index_name = read_stringref(p);
             if (_currType == ParseItem::ITEM_WAND) {
-                _currArg1 = readCompressedPositiveInt(p); // targetNumHits
-                _currArg2 = read_double(p); // scoreThreshold
-                _currArg3 = read_double(p); // thresholdBoostFactor
-            } else {
-                _currArg1 = 0;
+                _extraIntArg1 = readCompressedPositiveInt(p); // targetNumHits
+                _extraDoubleArg4 = read_double(p); // scoreThreshold
+                _extraDoubleArg5 = read_double(p); // thresholdBoostFactor
             }
             _curr_term = vespalib::stringref();
         } catch (...) {
@@ -274,7 +269,9 @@ SimpleQueryStackDumpIterator::next()
         try {
             _curr_index_name = read_stringref(p);
             _curr_term = read_stringref(p); // query_tensor_name
-            _currArg1 = readCompressedPositiveInt(p); // target_num_hits;
+            _extraIntArg1 = readCompressedPositiveInt(p); // targetNumHits
+            _extraIntArg2 = readCompressedPositiveInt(p); // allow_approximate
+            _extraIntArg3 = readCompressedPositiveInt(p); // explore_additional_hits
             _currArity = 0;
         } catch (...) {
             return false;
diff --git a/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.h b/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.h
index 6eb3fb7777d..73c97bb5fb3 100644
--- a/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.h
+++ b/searchlib/src/vespa/searchlib/parsequery/stackdumpiterator.h
@@ -42,12 +42,13 @@ private:
 
     /** The arity of the current item */
     uint32_t _currArity;
-    /** The first argument of the current item (length of NEAR/ONEAR area for example) */
-    uint32_t _currArg1;
-    /** The second argument of the current item (score threshold of WAND for example) */
-    double _currArg2;
-    /** The third argument of the current item (threshold boost factor of WAND for example) */
-    double _currArg3;
+
+    /* extra arguments */
+    uint32_t _extraIntArg1;
+    uint32_t _extraIntArg2;
+    uint32_t _extraIntArg3;
+    double _extraDoubleArg4;
+    double _extraDoubleArg5;
     /** The predicate query specification */
     query::PredicateQueryTerm::UP _predicate_query_term;
     /** The index name (field name) in the current item */
@@ -118,11 +119,12 @@ public:
 
     uint32_t getArity() const { return _currArity; }
 
-    uint32_t getArg1() const { return _currArg1; }
-
-    double getArg2() const { return _currArg2; }
-
-    double getArg3() const { return _currArg3; }
+    uint32_t getNearDistance() const { return _extraIntArg1; }
+    uint32_t getTargetNumHits() const { return _extraIntArg1; }
+    double getScoreThreshold() const { return _extraDoubleArg4; }
+    double getThresholdBoostFactor() const { return _extraDoubleArg5; }
+    bool getAllowApproximate() const { return (_extraIntArg2 != 0); }
+    uint32_t getExploreAdditionalHits() const { return _extraIntArg3; }
 
     query::PredicateQueryTerm::UP getPredicateQueryTerm()
     { return std::move(_predicate_query_term); }
diff --git a/searchlib/src/vespa/searchlib/query/streaming/querynode.cpp b/searchlib/src/vespa/searchlib/query/streaming/querynode.cpp
index 24c458c7e32..3db6c8e68c8 100644
--- a/searchlib/src/vespa/searchlib/query/streaming/querynode.cpp
+++ b/searchlib/src/vespa/searchlib/query/streaming/querynode.cpp
@@ -41,7 +41,7 @@ QueryNode::Build(const QueryNode * parent, const QueryNodeResultFactory & factor
             QueryConnector * qc = dynamic_cast<QueryConnector *> (qn.get());
             NearQueryNode * nqn = dynamic_cast<NearQueryNode *> (qc);
             if (nqn) {
-                nqn->distance(queryRep.getArg1());
+                nqn->distance(queryRep.getNearDistance());
             }
             if ((type == ParseItem::ITEM_WEAK_AND) ||
                 (type == ParseItem::ITEM_WEIGHTED_SET) ||
diff --git a/searchlib/src/vespa/searchlib/query/tree/querybuilder.h b/searchlib/src/vespa/searchlib/query/tree/querybuilder.h
index 797defc39f5..8e6f2944ec9 100644
--- a/searchlib/src/vespa/searchlib/query/tree/querybuilder.h
+++ b/searchlib/src/vespa/searchlib/query/tree/querybuilder.h
@@ -205,8 +205,11 @@ createRegExpTerm(vespalib::stringref term, vespalib::stringref view, int32_t id,
 template <class NodeTypes>
 typename NodeTypes::NearestNeighborTerm *
 create_nearest_neighbor_term(vespalib::stringref query_tensor_name, vespalib::stringref field_name,
-                             int32_t id, Weight weight, uint32_t target_num_hits) {
-    return new typename NodeTypes::NearestNeighborTerm(query_tensor_name, field_name, id, weight, target_num_hits);
+                             int32_t id, Weight weight, uint32_t target_num_hits,
+                             bool allow_approximate, uint32_t explore_additional_hits)
+{
+    return new typename NodeTypes::NearestNeighborTerm(query_tensor_name, field_name, id, weight,
+                                                       target_num_hits, allow_approximate, explore_additional_hits);
 }
 
 template <class NodeTypes>
@@ -317,9 +320,10 @@ public:
         return addTerm(createRegExpTerm<NodeTypes>(term, view, id, weight));
     }
     typename NodeTypes::NearestNeighborTerm &add_nearest_neighbor_term(stringref query_tensor_name, stringref field_name,
-                                                                       int32_t id, Weight weight, uint32_t target_num_hits) {
+                                                                       int32_t id, Weight weight, uint32_t target_num_hits,
+                                                                       bool allow_approximate, uint32_t explore_additional_hits) {
         adjustWeight(weight);
-        return addTerm(create_nearest_neighbor_term<NodeTypes>(query_tensor_name, field_name, id, weight, target_num_hits));
+        return addTerm(create_nearest_neighbor_term<NodeTypes>(query_tensor_name, field_name, id, weight, target_num_hits, allow_approximate, explore_additional_hits));
     }
 };
 
diff --git a/searchlib/src/vespa/searchlib/query/tree/queryreplicator.h b/searchlib/src/vespa/searchlib/query/tree/queryreplicator.h
index 0bf923960b9..9289df7cbe9 100644
--- a/searchlib/src/vespa/searchlib/query/tree/queryreplicator.h
+++ b/searchlib/src/vespa/searchlib/query/tree/queryreplicator.h
@@ -165,7 +165,8 @@ private:
 
     void visit(NearestNeighborTerm &node) override {
         replicate(node, _builder.add_nearest_neighbor_term(node.get_query_tensor_name(), node.getView(),
-                                                           node.getId(), node.getWeight(), node.get_target_num_hits()));
+                                                           node.getId(), node.getWeight(), node.get_target_num_hits(),
+                                                           node.get_allow_approximate(), node.get_explore_additional_hits()));
     }
 };
 
diff --git a/searchlib/src/vespa/searchlib/query/tree/simplequery.h b/searchlib/src/vespa/searchlib/query/tree/simplequery.h
index 8663bede4d6..4953f1a5b7c 100644
--- a/searchlib/src/vespa/searchlib/query/tree/simplequery.h
+++ b/searchlib/src/vespa/searchlib/query/tree/simplequery.h
@@ -105,8 +105,10 @@ struct SimpleRegExpTerm : RegExpTerm {
 };
 struct SimpleNearestNeighborTerm : NearestNeighborTerm {
     SimpleNearestNeighborTerm(vespalib::stringref query_tensor_name, vespalib::stringref field_name,
-                              int32_t id, Weight weight, uint32_t target_num_hits)
-        : NearestNeighborTerm(query_tensor_name, field_name, id, weight, target_num_hits)
+                              int32_t id, Weight weight, uint32_t target_num_hits,
+                              bool allow_approximate, uint32_t explore_additional_hits)
+        : NearestNeighborTerm(query_tensor_name, field_name, id, weight,
+                              target_num_hits, allow_approximate, explore_additional_hits)
     {}
 };
 
diff --git a/searchlib/src/vespa/searchlib/query/tree/stackdumpcreator.cpp b/searchlib/src/vespa/searchlib/query/tree/stackdumpcreator.cpp
index 63acf532144..aafeaa46a22 100644
--- a/searchlib/src/vespa/searchlib/query/tree/stackdumpcreator.cpp
+++ b/searchlib/src/vespa/searchlib/query/tree/stackdumpcreator.cpp
@@ -263,6 +263,8 @@ class QueryNodeConverter : public QueryVisitor {
         createTermNode(node, ParseItem::ITEM_NEAREST_NEIGHBOR);
         appendString(node.get_query_tensor_name());
         appendCompressedPositiveNumber(node.get_target_num_hits());
+        appendCompressedPositiveNumber(node.get_allow_approximate() ? 1 : 0);
+        appendCompressedPositiveNumber(node.get_explore_additional_hits());
     }
 
 public:
diff --git a/searchlib/src/vespa/searchlib/query/tree/stackdumpquerycreator.h b/searchlib/src/vespa/searchlib/query/tree/stackdumpquerycreator.h
index 791da010720..65d6abeeaad 100644
--- a/searchlib/src/vespa/searchlib/query/tree/stackdumpquerycreator.h
+++ b/searchlib/src/vespa/searchlib/query/tree/stackdumpquerycreator.h
@@ -48,9 +48,6 @@ public:
 private: 
     static Term * createQueryTerm(search::SimpleQueryStackDumpIterator &queryStack, QueryBuilder<NodeTypes> & builder, vespalib::stringref & pureTermView) {
         uint32_t arity = queryStack.getArity();
-        uint32_t arg1 = queryStack.getArg1();
-        double arg2 = queryStack.getArg2();
-        double arg3 = queryStack.getArg3();
         ParseItem::ItemType type = queryStack.getType();
         Node::UP node;
         Term *t = 0;
@@ -68,16 +65,19 @@ private:
             pureTermView = view;
         } else if (type == ParseItem::ITEM_WEAK_AND) {
             vespalib::stringref view = queryStack.getIndexName();
-            builder.addWeakAnd(arity, arg1, view);
+            uint32_t targetNumHits = queryStack.getTargetNumHits();
+            builder.addWeakAnd(arity, targetNumHits, view);
             pureTermView = view;
         } else if (type == ParseItem::ITEM_EQUIV) {
             int32_t id = queryStack.getUniqueId();
             Weight weight = queryStack.GetWeight();
             builder.addEquiv(arity, id, weight);
         } else if (type == ParseItem::ITEM_NEAR) {
-            builder.addNear(arity, arg1);
+            uint32_t nearDistance = queryStack.getNearDistance();
+            builder.addNear(arity, nearDistance);
         } else if (type == ParseItem::ITEM_ONEAR) {
-            builder.addONear(arity, arg1);
+            uint32_t nearDistance = queryStack.getNearDistance();
+            builder.addONear(arity, nearDistance);
         } else if (type == ParseItem::ITEM_PHRASE) {
             vespalib::stringref view = queryStack.getIndexName();
             int32_t id = queryStack.getUniqueId();
@@ -104,17 +104,24 @@ private:
             vespalib::stringref view = queryStack.getIndexName();
             int32_t id = queryStack.getUniqueId();
             Weight weight = queryStack.GetWeight();
-            t = &builder.addWandTerm(arity, view, id, weight, arg1, arg2, arg3);
+            uint32_t targetNumHits = queryStack.getTargetNumHits();
+            double scoreThreshold = queryStack.getScoreThreshold();
+            double thresholdBoostFactor = queryStack.getThresholdBoostFactor();
+            t = &builder.addWandTerm(arity, view, id, weight,
+                                     targetNumHits, scoreThreshold, thresholdBoostFactor);
             pureTermView = vespalib::stringref();
         } else if (type == ParseItem::ITEM_NOT) {
             builder.addAndNot(arity);
         } else if (type == ParseItem::ITEM_NEAREST_NEIGHBOR) {
             vespalib::stringref query_tensor_name = queryStack.getTerm();
             vespalib::stringref field_name = queryStack.getIndexName();
-            uint32_t target_num_hits = queryStack.getArg1();
+            uint32_t target_num_hits = queryStack.getTargetNumHits();
             int32_t id = queryStack.getUniqueId();
             Weight weight = queryStack.GetWeight();
-            builder.add_nearest_neighbor_term(query_tensor_name, field_name, id, weight, target_num_hits);
+            bool allow_approximate = queryStack.getAllowApproximate();
+            uint32_t explore_additional_hits = queryStack.getExploreAdditionalHits();
+            builder.add_nearest_neighbor_term(query_tensor_name, field_name, id, weight,
+                                              target_num_hits, allow_approximate, explore_additional_hits);
         } else {
             vespalib::stringref term = queryStack.getTerm();
             vespalib::stringref view = queryStack.getIndexName();
diff --git a/searchlib/src/vespa/searchlib/query/tree/termnodes.h b/searchlib/src/vespa/searchlib/query/tree/termnodes.h
index a82b1e14d76..9af424716fb 100644
--- a/searchlib/src/vespa/searchlib/query/tree/termnodes.h
+++ b/searchlib/src/vespa/searchlib/query/tree/termnodes.h
@@ -128,17 +128,24 @@ class NearestNeighborTerm : public QueryNodeMixin<NearestNeighborTerm, TermNode>
 private:
     vespalib::string _query_tensor_name;
     uint32_t _target_num_hits;
+    bool _allow_approximate;
+    uint32_t _explore_additional_hits;
 
 public:
     NearestNeighborTerm(vespalib::stringref query_tensor_name, vespalib::stringref field_name,
-                        int32_t id, Weight weight, uint32_t target_num_hits)
+                        int32_t id, Weight weight, uint32_t target_num_hits,
+                        bool allow_approximate, uint32_t explore_additional_hits)
         : QueryNodeMixinType(field_name, id, weight),
           _query_tensor_name(query_tensor_name),
-          _target_num_hits(target_num_hits)
+          _target_num_hits(target_num_hits),
+          _allow_approximate(allow_approximate),
+          _explore_additional_hits(explore_additional_hits)
     {}
     virtual ~NearestNeighborTerm() {}
     const vespalib::string& get_query_tensor_name() const { return _query_tensor_name; }
     uint32_t get_target_num_hits() const { return _target_num_hits; }
+    bool get_allow_approximate() const { return _allow_approximate; }
+    uint32_t get_explore_additional_hits() const { return _explore_additional_hits; }
 };
 
 
diff --git a/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.cpp b/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.cpp
index d4aa2aaa1d7..d3b2925e075 100644
--- a/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.cpp
+++ b/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.cpp
@@ -13,11 +13,13 @@ namespace search::queryeval {
 NearestNeighborBlueprint::NearestNeighborBlueprint(const queryeval::FieldSpec& field,
                                                    const tensor::DenseTensorAttribute& attr_tensor,
                                                    std::unique_ptr<vespalib::tensor::DenseTensorView> query_tensor,
-                                                   uint32_t target_num_hits)
+                                                   uint32_t target_num_hits, bool approximate, uint32_t explore_additional_hits)
     : ComplexLeafBlueprint(field),
       _attr_tensor(attr_tensor),
       _query_tensor(std::move(query_tensor)),
       _target_num_hits(target_num_hits),
+      _approximate(approximate),
+      _explore_additional_hits(explore_additional_hits),
       _distance_heap(target_num_hits),
       _found_hits()
 {
@@ -34,15 +36,14 @@ void
 NearestNeighborBlueprint::perform_top_k()
 {
     auto nns_index = _attr_tensor.nearest_neighbor_index();
-    if (nns_index) {
+    if (_approximate && nns_index) {
         auto lhs_type = _query_tensor->fast_type();
         auto rhs_type = _attr_tensor.getTensorType();
         // XXX deal with different cell types later
         if (lhs_type == rhs_type) {
             auto lhs = _query_tensor->cellsRef();
             uint32_t k = _target_num_hits;
-            uint32_t explore_k = k + 100; // XXX hardcoded for now
-            _found_hits = nns_index->find_top_k(k, lhs, explore_k);
+            _found_hits = nns_index->find_top_k(k, lhs, k + _explore_additional_hits);
         }
     }
 }
@@ -73,6 +74,8 @@ NearestNeighborBlueprint::visitMembers(vespalib::ObjectVisitor& visitor) const
     visitor.visitString("attribute_tensor", _attr_tensor.getTensorType().to_spec());
     visitor.visitString("query_tensor", _query_tensor->type().to_spec());
     visitor.visitInt("target_num_hits", _target_num_hits);
+    visitor.visitBool("approximate", _approximate);
+    visitor.visitInt("explore_additional_hits", _explore_additional_hits);
 }
 
 bool
diff --git a/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.h b/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.h
index ab4413c487a..39165b066be 100644
--- a/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.h
+++ b/searchlib/src/vespa/searchlib/queryeval/nearest_neighbor_blueprint.h
@@ -21,6 +21,8 @@ private:
     const tensor::DenseTensorAttribute& _attr_tensor;
     std::unique_ptr<vespalib::tensor::DenseTensorView> _query_tensor;
     uint32_t _target_num_hits;
+    bool _approximate;
+    uint32_t _explore_additional_hits;
     mutable NearestNeighborDistanceHeap _distance_heap;
     std::vector<search::tensor::NearestNeighborIndex::Neighbor> _found_hits;
 
@@ -29,7 +31,7 @@ public:
     NearestNeighborBlueprint(const queryeval::FieldSpec& field,
                              const tensor::DenseTensorAttribute& attr_tensor,
                              std::unique_ptr<vespalib::tensor::DenseTensorView> query_tensor,
-                             uint32_t target_num_hits);
+                             uint32_t target_num_hits, bool approximate, uint32_t explore_additional_hits);
     NearestNeighborBlueprint(const NearestNeighborBlueprint&) = delete;
     NearestNeighborBlueprint& operator=(const NearestNeighborBlueprint&) = delete;
     ~NearestNeighborBlueprint();