Add filtering support to attribute combiner dynamic field writer.

12 files changed, 187 insertions, 47 deletions

diff --git a/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp b/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp
index 01b458daf5d..240e7334292 100644
--- a/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp
+++ b/searchsummary/src/tests/docsummary/attribute_combiner/attribute_combiner_test.cpp
@@ -8,6 +8,7 @@
 #include <vespa/searchlib/attribute/floatbase.h>
 #include <vespa/searchlib/attribute/integerbase.h>
 #include <vespa/searchlib/attribute/stringbase.h>
+#include <vespa/searchlib/common/matching_elements.h>
 #include <vespa/searchlib/util/slime_output_raw_buf_adapter.h>
 #include <vespa/searchsummary/docsummary/docsumstate.h>
 #include <vespa/searchsummary/docsummary/docsum_field_writer_state.h>
@@ -23,6 +24,7 @@ using search::AttributeManager;
 using search::AttributeVector;
 using search::IntegerAttribute;
 using search::FloatingPointAttribute;
+using search::MatchingElements;
 using search::StringAttribute;
 using search::attribute::BasicType;
 using search::attribute::CollectionType;
@@ -157,12 +159,30 @@ AttributeManagerFixture::buildIntegerAttribute(const vespalib::string &name,
 class DummyStateCallback : public GetDocsumsStateCallback
 {
 public:
+    MatchingElements _matching_elements;
+
+    DummyStateCallback();
     void FillSummaryFeatures(GetDocsumsState *, IDocsumEnvironment *) override { }
     void FillRankFeatures(GetDocsumsState *, IDocsumEnvironment *) override { }
     void ParseLocation(GetDocsumsState *) override { }
+    const MatchingElements& fill_matching_elements() override { return _matching_elements; }
     ~DummyStateCallback() override { }
 };
 
+DummyStateCallback::DummyStateCallback()
+    : GetDocsumsStateCallback(),
+      _matching_elements()
+{
+    _matching_elements.add_matching_elements(1, "array", {1});
+    _matching_elements.add_matching_elements(3, "array", {0});
+    _matching_elements.add_matching_elements(4, "array", {1});
+    _matching_elements.add_matching_elements(1, "smap", {1});
+    _matching_elements.add_matching_elements(3, "smap", {0});
+    _matching_elements.add_matching_elements(4, "smap", {1});
+    _matching_elements.add_matching_elements(1, "map", {1});
+    _matching_elements.add_matching_elements(3, "map", {0});
+    _matching_elements.add_matching_elements(4, "map", {1});
+}
 
 struct AttributeCombinerTest : public ::testing::Test
 {
@@ -173,7 +193,7 @@ struct AttributeCombinerTest : public ::testing::Test
 
     AttributeCombinerTest();
     ~AttributeCombinerTest();
-    void set_field_name(const vespalib::string &field_name);
+    void set_field(const vespalib::string &field_name, bool filter_elements);
     void assertWritten(const vespalib::string &exp, uint32_t docId);
 };
 
@@ -189,9 +209,9 @@ AttributeCombinerTest::AttributeCombinerTest()
 AttributeCombinerTest::~AttributeCombinerTest() = default;
 
 void
-AttributeCombinerTest::set_field_name(const vespalib::string &field_name)
+AttributeCombinerTest::set_field(const vespalib::string &field_name, bool filter_elements)
 {
-    writer = AttributeCombinerDFW::create(field_name, attrs.mgr);
+    writer = AttributeCombinerDFW::create(field_name, attrs.mgr, filter_elements);
     EXPECT_TRUE(writer->setFieldWriterStateIndex(0));
     state._fieldWriterStates.resize(1);
 }
@@ -219,7 +239,7 @@ AttributeCombinerTest::assertWritten(const vespalib::string &expectedJson, uint3
 
 TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_correct_slime_output_for_array_of_struct)
 {
-    set_field_name("array");
+    set_field("array", false);
     assertWritten("[ { fval: 110.0, name: \"n1.1\", val: 10}, { name: \"n1.2\", val: 11}]", 1);
     assertWritten("[ { fval: 120.0, name: \"n2\", val: 20}, { fval: 121.0, val: 21 }]", 2);
     assertWritten("[ { fval: 130.0, name: \"n3.1\", val: 30}, { fval: 131.0, name: \"n3.2\"} ]", 3);
@@ -229,7 +249,7 @@ TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_corr
 
 TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_correct_slime_output_for_map_of_struct)
 {
-    set_field_name("smap");
+    set_field("smap", false);
     assertWritten("[ { key: \"k1.1\", value: { fval: 110.0, name: \"n1.1\", val: 10} }, { key: \"k1.2\", value: { name: \"n1.2\", val: 11} }]", 1);
     assertWritten("[ { key: \"k2\", value: { fval: 120.0, name: \"n2\", val: 20} }, { value: { fval: 121.0, val: 21 } }]", 2);
     assertWritten("[ { key: \"k3.1\", value: { fval: 130.0, name: \"n3.1\", val: 30} }, { key: \"k3.2\", value: { fval: 131.0, name: \"n3.2\"} } ]", 3);
@@ -239,7 +259,7 @@ TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_corr
 
 TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_correct_slime_output_for_map_of_string)
 {
-    set_field_name("map");
+    set_field("map", false);
     assertWritten("[ { key: \"k1.1\", value: \"n1.1\" }, { key: \"k1.2\", value: \"n1.2\"}]", 1);
     assertWritten("[ { key: \"k2\"}]", 2);
     assertWritten("[ { key: \"k3.1\", value: \"n3.1\" }, { value: \"n3.2\"} ]", 3);
@@ -247,6 +267,36 @@ TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_corr
     assertWritten("null", 5);
 }
 
+TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_correct_slime_output_for_filtered_array_of_struct)
+{
+    set_field("array", true);
+    assertWritten("[ { name: \"n1.2\", val: 11}]", 1);
+    assertWritten("[ ]", 2);
+    assertWritten("[ { fval: 130.0, name: \"n3.1\", val: 30} ]", 3);
+    assertWritten("[ { fval: 141.0, name: \"n4.2\", val:  41} ]", 4);
+    assertWritten("null", 5);
+}
+
+TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_correct_slime_output_for_filtered_map_of_struct)
+{
+    set_field("smap", true);
+    assertWritten("[ { key: \"k1.2\", value: { name: \"n1.2\", val: 11} }]", 1);
+    assertWritten("[ ]", 2);
+    assertWritten("[ { key: \"k3.1\", value: { fval: 130.0, name: \"n3.1\", val: 30} } ]", 3);
+    assertWritten("[ { key: \"k4.2\", value: { fval: 141.0, name: \"n4.2\", val:  41} } ]", 4);
+    assertWritten("null", 5);
+}
+
+TEST_F(AttributeCombinerTest, require_that_attribute_combiner_dfw_generates_correct_slime_output_for_filtered_map_of_string)
+{
+    set_field("map", true);
+    assertWritten("[ { key: \"k1.2\", value: \"n1.2\"}]", 1);
+    assertWritten("[ ]", 2);
+    assertWritten("[ { key: \"k3.1\", value: \"n3.1\" } ]", 3);
+    assertWritten("[ { key: \"k4.2\", value: \"n4.2\" } ]", 4);
+    assertWritten("null", 5);
+}
+
 }
 
 GTEST_MAIN_RUN_ALL_TESTS()
diff --git a/searchsummary/src/tests/docsummary/positionsdfw_test.cpp b/searchsummary/src/tests/docsummary/positionsdfw_test.cpp
index 764ff4723cb..86a2e9ae76f 100644
--- a/searchsummary/src/tests/docsummary/positionsdfw_test.cpp
+++ b/searchsummary/src/tests/docsummary/positionsdfw_test.cpp
@@ -3,6 +3,7 @@
 
 #include <vespa/searchlib/attribute/extendableattributes.h>
 #include <vespa/searchlib/attribute/iattributemanager.h>
+#include <vespa/searchlib/common/matching_elements.h>
 #include <vespa/searchsummary/docsummary/docsumfieldwriter.h>
 #include <vespa/searchsummary/docsummary/positionsdfw.h>
 #include <vespa/searchsummary/docsummary/idocsumenvironment.h>
@@ -17,6 +18,7 @@ LOG_SETUP("positionsdfw_test");
 
 using search::RawBuf;
 using search::IAttributeManager;
+using search::MatchingElements;
 using search::SingleInt64ExtAttribute;
 using search::attribute::IAttributeContext;
 using search::attribute::IAttributeVector;
@@ -104,6 +106,7 @@ struct MyGetDocsumsStateCallback : GetDocsumsStateCallback {
     virtual void FillSummaryFeatures(GetDocsumsState *, IDocsumEnvironment *) override {}
     virtual void FillRankFeatures(GetDocsumsState *, IDocsumEnvironment *) override {}
     virtual void ParseLocation(GetDocsumsState *) override {}
+    const MatchingElements& fill_matching_elements() override { abort(); }
 };
 
 template <typename AttrType>
diff --git a/searchsummary/src/tests/docsummary/slime_summary/slime_summary_test.cpp b/searchsummary/src/tests/docsummary/slime_summary/slime_summary_test.cpp
index 5d6565ceadb..bd753f24bf3 100644
--- a/searchsummary/src/tests/docsummary/slime_summary/slime_summary_test.cpp
+++ b/searchsummary/src/tests/docsummary/slime_summary/slime_summary_test.cpp
@@ -1,5 +1,6 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 #include <vespa/vespalib/testkit/test_kit.h>
+#include <vespa/searchlib/common/matching_elements.h>
 #include <vespa/searchsummary/docsummary/docsumwriter.h>
 #include <vespa/searchsummary/docsummary/resultpacker.h>
 #include <vespa/searchsummary/docsummary/docsumstate.h>
@@ -9,6 +10,7 @@
 
 using namespace vespalib::slime::convenience;
 using namespace search::docsummary;
+using search::MatchingElements;
 
 namespace {
 
@@ -77,6 +79,7 @@ struct DocsumFixture : IDocsumStore, GetDocsumsStateCallback {
     void FillSummaryFeatures(GetDocsumsState *, IDocsumEnvironment *) override { }
     void FillRankFeatures(GetDocsumsState *, IDocsumEnvironment *) override { }
     void ParseLocation(GetDocsumsState *) override { }
+    const MatchingElements& fill_matching_elements() override { abort(); }
 };
 
 
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp b/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp
index 6a643a74458..9d4d3829047 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.cpp
@@ -5,7 +5,9 @@
 #include "attribute_field_writer.h"
 #include <vespa/searchcommon/attribute/iattributecontext.h>
 #include <vespa/searchcommon/attribute/iattributevector.h>
+#include <vespa/searchlib/common/matching_elements.h>
 #include <vespa/vespalib/data/slime/cursor.h>
+#include <cassert>
 
 using search::attribute::IAttributeContext;
 using search::attribute::IAttributeVector;
@@ -18,20 +20,29 @@ namespace {
 class ArrayAttributeFieldWriterState : public DocsumFieldWriterState
 {
     std::vector<std::unique_ptr<AttributeFieldWriter>> _writers;
+    const vespalib::string&                            _field_name;
+    const MatchingElements* const                      _matching_elements;
 
 public:
     ArrayAttributeFieldWriterState(const std::vector<vespalib::string> &fieldNames,
                                    const std::vector<vespalib::string> &attributeNames,
-                                   IAttributeContext &context);
+                                   IAttributeContext &context,
+                                   const vespalib::string &field_name,
+                                   const MatchingElements* matching_elements);
     ~ArrayAttributeFieldWriterState() override;
+    void insert_element(uint32_t element_index, Cursor &array);
     void insertField(uint32_t docId, vespalib::slime::Inserter &target) override;
 };
 
 ArrayAttributeFieldWriterState::ArrayAttributeFieldWriterState(const std::vector<vespalib::string> &fieldNames,
                                                                const std::vector<vespalib::string> &attributeNames,
-                                                               IAttributeContext &context)
+                                                               IAttributeContext &context,
+                                                               const vespalib::string &field_name,
+                                                               const MatchingElements *matching_elements)
     : DocsumFieldWriterState(),
-      _writers()
+      _writers(),
+    _field_name(field_name),
+      _matching_elements(matching_elements)
 {
     size_t fields = fieldNames.size();
     _writers.reserve(fields);
@@ -46,6 +57,15 @@ ArrayAttributeFieldWriterState::ArrayAttributeFieldWriterState(const std::vector
 ArrayAttributeFieldWriterState::~ArrayAttributeFieldWriterState() = default;
 
 void
+ArrayAttributeFieldWriterState::insert_element(uint32_t element_index, Cursor &array)
+{
+    Cursor &obj = array.addObject();
+    for (auto &writer : _writers) {
+        writer->print(element_index, obj);
+    }
+}
+
+void
 ArrayAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime::Inserter &target)
 {
     uint32_t elems = 0;
@@ -59,10 +79,19 @@ ArrayAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime::Ins
         return;
     }
     Cursor &arr = target.insertArray();
-    for (uint32_t idx = 0; idx < elems; ++idx) {
-        Cursor &obj = arr.addObject();
-        for (auto &writer : _writers) {
-            writer->print(idx, obj);
+    if (_matching_elements != nullptr) {
+        auto &elements = _matching_elements->get_matching_elements(docId, _field_name);
+        auto elements_iterator = elements.cbegin();
+        for (uint32_t idx = 0; idx < elems && elements_iterator != elements.cend(); ++idx) {
+            assert(*elements_iterator >= idx);
+            if (*elements_iterator == idx) {
+                insert_element(idx, arr);
+                ++elements_iterator;
+            }
+        }
+    } else {
+        for (uint32_t idx = 0; idx < elems; ++idx) {
+            insert_element(idx, arr);
         }
     }
 }
@@ -70,8 +99,9 @@ ArrayAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime::Ins
 }
 
 ArrayAttributeCombinerDFW::ArrayAttributeCombinerDFW(const vespalib::string &fieldName,
-                                                     const std::vector<vespalib::string> &fields)
-    : AttributeCombinerDFW(fieldName),
+                                                     const std::vector<vespalib::string> &fields,
+                                                     bool filter_elements)
+    : AttributeCombinerDFW(fieldName, filter_elements),
       _fields(fields),
       _attributeNames()
 {
@@ -85,9 +115,9 @@ ArrayAttributeCombinerDFW::ArrayAttributeCombinerDFW(const vespalib::string &fie
 ArrayAttributeCombinerDFW::~ArrayAttributeCombinerDFW() = default;
 
 std::unique_ptr<DocsumFieldWriterState>
-ArrayAttributeCombinerDFW::allocFieldWriterState(IAttributeContext &context)
+ArrayAttributeCombinerDFW::allocFieldWriterState(IAttributeContext &context, const MatchingElements* matching_elements)
 {
-    return std::make_unique<ArrayAttributeFieldWriterState>(_fields, _attributeNames, context);
+    return std::make_unique<ArrayAttributeFieldWriterState>(_fields, _attributeNames, context, _fieldName, matching_elements);
 }
 
 }
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.h b/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.h
index c02d2bd5da6..15c3030c782 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.h
+++ b/searchsummary/src/vespa/searchsummary/docsummary/array_attribute_combiner_dfw.h
@@ -19,10 +19,11 @@ class ArrayAttributeCombinerDFW : public AttributeCombinerDFW
     std::vector<vespalib::string> _fields;
     std::vector<vespalib::string> _attributeNames;
 
-    std::unique_ptr<DocsumFieldWriterState> allocFieldWriterState(search::attribute::IAttributeContext &context) override;
+    std::unique_ptr<DocsumFieldWriterState> allocFieldWriterState(search::attribute::IAttributeContext &context, const MatchingElements* matching_elements) override;
 public:
     ArrayAttributeCombinerDFW(const vespalib::string &fieldName,
-                              const std::vector<vespalib::string> &fields);
+                              const std::vector<vespalib::string> &fields,
+                              bool filter_elements);
     ~ArrayAttributeCombinerDFW() override;
 };
 
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.cpp b/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.cpp
index ef621dc5b4a..ed053ce0115 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.cpp
@@ -89,9 +89,10 @@ StructFields::~StructFields() = default;
 
 }
 
-AttributeCombinerDFW::AttributeCombinerDFW(const vespalib::string &fieldName)
+AttributeCombinerDFW::AttributeCombinerDFW(const vespalib::string &fieldName, bool filter_elements)
     : ISimpleDFW(),
       _stateIndex(0),
+      _filter_elements(filter_elements),
       _fieldName(fieldName)
 {
 }
@@ -112,15 +113,15 @@ AttributeCombinerDFW::setFieldWriterStateIndex(uint32_t fieldWriterStateIndex)
 }
 
 std::unique_ptr<IDocsumFieldWriter>
-AttributeCombinerDFW::create(const vespalib::string &fieldName, IAttributeManager &attrMgr)
+AttributeCombinerDFW::create(const vespalib::string &fieldName, IAttributeManager &attrMgr, bool filter_elements)
 {
     StructFields structFields(fieldName, attrMgr);
     if (structFields.getError()) {
         return std::unique_ptr<IDocsumFieldWriter>();
     } else if (!structFields.getMapFields().empty()) {
-        return std::make_unique<StructMapAttributeCombinerDFW>(fieldName, structFields.getMapFields());
+        return std::make_unique<StructMapAttributeCombinerDFW>(fieldName, structFields.getMapFields(), filter_elements);
     }
-    return std::make_unique<ArrayAttributeCombinerDFW>(fieldName, structFields.getArrayFields());
+    return std::make_unique<ArrayAttributeCombinerDFW>(fieldName, structFields.getArrayFields(), filter_elements);
 }
 
 void
@@ -128,7 +129,11 @@ AttributeCombinerDFW::insertField(uint32_t docid, GetDocsumsState *state, ResTyp
 {
     auto &fieldWriterState = state->_fieldWriterStates[_stateIndex];
     if (!fieldWriterState) {
-        fieldWriterState = allocFieldWriterState(*state->_attrCtx);
+        const MatchingElements *matching_elements = nullptr;
+        if (_filter_elements) {
+            matching_elements = &state->get_matching_elements();
+        }
+        fieldWriterState = allocFieldWriterState(*state->_attrCtx, matching_elements);
     }
     fieldWriterState->insertField(docid, target);
 }
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.h b/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.h
index 6c0991fdf92..ec806ba0ac6 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.h
+++ b/searchsummary/src/vespa/searchsummary/docsummary/attribute_combiner_dfw.h
@@ -4,6 +4,7 @@
 
 #include "docsumfieldwriter.h"
 
+namespace search { class MatchingElements; }
 namespace search::attribute { class IAttributeContext; }
 
 namespace search::docsummary {
@@ -19,15 +20,16 @@ class AttributeCombinerDFW : public ISimpleDFW
 {
 protected:
     uint32_t _stateIndex;
+    const bool _filter_elements;
     vespalib::string _fieldName;
-    AttributeCombinerDFW(const vespalib::string &fieldName);
+    AttributeCombinerDFW(const vespalib::string &fieldName, bool filter_elements);
 protected:
-    virtual std::unique_ptr<DocsumFieldWriterState> allocFieldWriterState(search::attribute::IAttributeContext &context) = 0;
+    virtual std::unique_ptr<DocsumFieldWriterState> allocFieldWriterState(search::attribute::IAttributeContext &context, const MatchingElements* matching_elements) = 0;
 public:
     ~AttributeCombinerDFW() override;
     bool IsGenerated() const override;
     bool setFieldWriterStateIndex(uint32_t fieldWriterStateIndex) override;
-    static std::unique_ptr<IDocsumFieldWriter> create(const vespalib::string &fieldName, IAttributeManager &attrMgr);
+    static std::unique_ptr<IDocsumFieldWriter> create(const vespalib::string &fieldName, IAttributeManager &attrMgr, bool filter_elements);
     void insertField(uint32_t docid, GetDocsumsState *state, ResType type, vespalib::slime::Inserter &target) override;
 };
 
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/docsumconfig.cpp b/searchsummary/src/vespa/searchsummary/docsummary/docsumconfig.cpp
index b95591546b5..f6377563d90 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/docsumconfig.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/docsumconfig.cpp
@@ -94,7 +94,7 @@ DynamicDocsumConfig::createFieldWriter(const string & fieldName, const string &
         }
     } else if (overrideName == "attributecombiner") {
         if (getEnvironment() && getEnvironment()->getAttributeManager()) {
-            fieldWriter = AttributeCombinerDFW::create(fieldName, *getEnvironment()->getAttributeManager());
+            fieldWriter = AttributeCombinerDFW::create(fieldName, *getEnvironment()->getAttributeManager(), false);
             rc = static_cast<bool>(fieldWriter);
         }
     } else {
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.cpp b/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.cpp
index b0431b6e6ac..d78c908fa6a 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.cpp
@@ -4,10 +4,10 @@
 #include <vespa/juniper/rpinterface.h>
 #include <vespa/searchcommon/attribute/iattributecontext.h>
 #include <vespa/searchlib/common/location.h>
+#include <vespa/searchlib/common/matching_elements.h>
 #include "docsum_field_writer_state.h"
 
-namespace search {
-namespace docsummary {
+namespace search::docsummary {
 
 GetDocsumsState::GetDocsumsState(GetDocsumsStateCallback &callback)
     : _args(),
@@ -25,7 +25,8 @@ GetDocsumsState::GetDocsumsState(GetDocsumsStateCallback &callback)
       _parsedLocation(),
       _summaryFeatures(NULL),
       _summaryFeaturesCached(false),
-      _rankFeatures(NULL)
+      _rankFeatures(NULL),
+      _matching_elements(nullptr)
 {
     _dynteaser._docid    = static_cast<uint32_t>(-1);
     _dynteaser._input    = static_cast<uint32_t>(-1);
@@ -48,5 +49,13 @@ GetDocsumsState::~GetDocsumsState()
     }
 }
 
+const MatchingElements &
+GetDocsumsState::get_matching_elements()
+{
+    if (_matching_elements == nullptr) {
+        _matching_elements = &_callback.fill_matching_elements();
+    }
+    return *_matching_elements;
 }
+
 }
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.h b/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.h
index fa47d5244eb..394913d3ad9 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.h
+++ b/searchsummary/src/vespa/searchsummary/docsummary/docsumstate.h
@@ -13,6 +13,7 @@ namespace juniper {
     class Result;
 }
 
+namespace search { class MatchingElements; }
 namespace search::common { class Location; }
 namespace search::attribute {
     class IAttributeContext;
@@ -31,6 +32,7 @@ public:
     virtual void FillSummaryFeatures(GetDocsumsState * state, IDocsumEnvironment * env) = 0;
     virtual void FillRankFeatures(GetDocsumsState * state, IDocsumEnvironment * env) = 0;
     virtual void ParseLocation(GetDocsumsState * state) = 0;
+    virtual const MatchingElements& fill_matching_elements() = 0;
     virtual ~GetDocsumsStateCallback(void) { }
     GetDocsumsStateCallback(const GetDocsumsStateCallback &) = delete;
     GetDocsumsStateCallback & operator = (const GetDocsumsStateCallback &) = delete;
@@ -84,10 +86,14 @@ public:
     // used by RankFeaturesDFW
     FeatureSet::SP _rankFeatures;
 
+    // Used by AttributeCombinerDFW when filtering is enabled
+    const search::MatchingElements* _matching_elements;
+
     GetDocsumsState(const GetDocsumsState &) = delete;
     GetDocsumsState& operator=(const GetDocsumsState &) = delete;
     GetDocsumsState(GetDocsumsStateCallback &callback);
     ~GetDocsumsState();
+    const MatchingElements &get_matching_elements();
 };
 
 }
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp b/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp
index e4e30afbc4d..e34012de7de 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp
+++ b/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.cpp
@@ -5,7 +5,9 @@
 #include "attribute_field_writer.h"
 #include <vespa/searchcommon/attribute/iattributecontext.h>
 #include <vespa/searchcommon/attribute/iattributevector.h>
+#include <vespa/searchlib/common/matching_elements.h>
 #include <vespa/vespalib/data/slime/cursor.h>
+#include <cassert>
 
 using search::attribute::IAttributeContext;
 using search::attribute::IAttributeVector;
@@ -22,23 +24,32 @@ class StructMapAttributeFieldWriterState : public DocsumFieldWriterState
 {
     std::unique_ptr<AttributeFieldWriter> _keyWriter;
     std::vector<std::unique_ptr<AttributeFieldWriter>> _valueWriters;
+    const vespalib::string&                            _field_name; 
+    const MatchingElements* const                      _matching_elements;
 
 public:
     StructMapAttributeFieldWriterState(const vespalib::string &keyAttributeName,
                                        const std::vector<vespalib::string> &valueFieldNames,
                                        const std::vector<vespalib::string> &valueAttributeNames,
-                                       IAttributeContext &context);
+                                       IAttributeContext &context,
+                                       const vespalib::string &field_name,
+                                       const MatchingElements* matching_elements);
     ~StructMapAttributeFieldWriterState() override;
+    void insert_element(uint32_t element_index, Cursor &array);
     void insertField(uint32_t docId, vespalib::slime::Inserter &target) override;
 };
 
 StructMapAttributeFieldWriterState::StructMapAttributeFieldWriterState(const vespalib::string &keyAttributeName,
                                                                        const std::vector<vespalib::string> &valueFieldNames,
                                                                        const std::vector<vespalib::string> &valueAttributeNames,
-                                                                       IAttributeContext &context)
+                                                                       IAttributeContext &context,
+                                                                       const vespalib::string& field_name, 
+                                                                       const MatchingElements *matching_elements)
     : DocsumFieldWriterState(),
       _keyWriter(),
-      _valueWriters()
+      _valueWriters(),
+      _field_name(field_name),
+      _matching_elements(matching_elements)
 {
     const IAttributeVector *attr = context.getAttribute(keyAttributeName);
     if (attr != nullptr) {
@@ -57,6 +68,19 @@ StructMapAttributeFieldWriterState::StructMapAttributeFieldWriterState(const ves
 StructMapAttributeFieldWriterState::~StructMapAttributeFieldWriterState() = default;
 
 void
+StructMapAttributeFieldWriterState::insert_element(uint32_t element_index, Cursor &array)
+{
+    Cursor &keyValueObj = array.addObject();
+    if (_keyWriter) {
+        _keyWriter->print(element_index, keyValueObj);
+    }
+    Cursor &obj = keyValueObj.setObject(valueName);
+    for (auto &valueWriter : _valueWriters) {
+        valueWriter->print(element_index, obj);
+    }
+}
+
+void
 StructMapAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime::Inserter &target)
 {
     uint32_t elems = 0;
@@ -76,14 +100,19 @@ StructMapAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime:
         return;
     }
     Cursor &arr = target.insertArray();
-    for (uint32_t idx = 0; idx < elems; ++idx) {
-        Cursor &keyValueObj = arr.addObject();
-        if (_keyWriter) {
-            _keyWriter->print(idx, keyValueObj);
+    if (_matching_elements != nullptr) {
+        auto &elements = _matching_elements->get_matching_elements(docId, _field_name);
+        auto elements_iterator = elements.cbegin();
+        for (uint32_t idx = 0; idx < elems && elements_iterator != elements.cend(); ++idx) {
+            assert(*elements_iterator >= idx);
+            if (*elements_iterator == idx) {
+                insert_element(idx, arr);
+                ++elements_iterator;
+            }
         }
-        Cursor &obj = keyValueObj.setObject(valueName);
-        for (auto &valueWriter : _valueWriters) {
-            valueWriter->print(idx, obj);
+    } else {
+        for (uint32_t idx = 0; idx < elems; ++idx) {
+            insert_element(idx, arr);
         }
     }
 }
@@ -91,8 +120,9 @@ StructMapAttributeFieldWriterState::insertField(uint32_t docId, vespalib::slime:
 }
 
 StructMapAttributeCombinerDFW::StructMapAttributeCombinerDFW(const vespalib::string &fieldName,
-                                                             const std::vector<vespalib::string> &valueFields)
-    : AttributeCombinerDFW(fieldName),
+                                                             const std::vector<vespalib::string> &valueFields,
+                                                             bool filter_elements)
+    : AttributeCombinerDFW(fieldName, filter_elements),
       _keyAttributeName(),
       _valueFields(valueFields),
       _valueAttributeNames()
@@ -108,9 +138,9 @@ StructMapAttributeCombinerDFW::StructMapAttributeCombinerDFW(const vespalib::str
 StructMapAttributeCombinerDFW::~StructMapAttributeCombinerDFW() = default;
 
 std::unique_ptr<DocsumFieldWriterState>
-StructMapAttributeCombinerDFW::allocFieldWriterState(IAttributeContext &context)
+StructMapAttributeCombinerDFW::allocFieldWriterState(IAttributeContext &context, const MatchingElements* matching_elements)
 {
-    return std::make_unique<StructMapAttributeFieldWriterState>(_keyAttributeName, _valueFields, _valueAttributeNames, context);
+    return std::make_unique<StructMapAttributeFieldWriterState>(_keyAttributeName, _valueFields, _valueAttributeNames, context, _fieldName, matching_elements);
 }
 
 }
diff --git a/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.h b/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.h
index 99ad007559b..375d55df678 100644
--- a/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.h
+++ b/searchsummary/src/vespa/searchsummary/docsummary/struct_map_attribute_combiner_dfw.h
@@ -20,10 +20,11 @@ class StructMapAttributeCombinerDFW : public AttributeCombinerDFW
     std::vector<vespalib::string> _valueFields;
     std::vector<vespalib::string> _valueAttributeNames;
 
-    std::unique_ptr<DocsumFieldWriterState> allocFieldWriterState(search::attribute::IAttributeContext &context) override;
+    std::unique_ptr<DocsumFieldWriterState> allocFieldWriterState(search::attribute::IAttributeContext &context, const MatchingElements* matching_elements) override;
 public:
     StructMapAttributeCombinerDFW(const vespalib::string &fieldName,
-                              const std::vector<vespalib::string> &valueFields);
+                                  const std::vector<vespalib::string> &valueFields,
+                                  bool filter_elements);
     ~StructMapAttributeCombinerDFW() override;
 };