Refactored to allow iteration over matching elements.

18 files changed, 202 insertions, 203 deletions

diff --git a/searchcommon/src/vespa/searchcommon/attribute/i_search_context.h b/searchcommon/src/vespa/searchcommon/attribute/i_search_context.h
index 4be1f00dcbc..3eede13c42d 100644
--- a/searchcommon/src/vespa/searchcommon/attribute/i_search_context.h
+++ b/searchcommon/src/vespa/searchcommon/attribute/i_search_context.h
@@ -24,8 +24,8 @@ public:
     using DocId = uint32_t;
 
 private:
-    virtual bool onCmp(DocId docId, int32_t &weight) const = 0;
-    virtual bool onCmp(DocId docId) const = 0;
+    virtual int32_t onCmp(DocId docId, int32_t elementId, int32_t &weight) const = 0;
+    virtual int32_t onCmp(DocId docId, int32_t elementId) const = 0;
 
 public:
     virtual ~ISearchContext() {}
@@ -57,8 +57,10 @@ public:
     virtual const QueryTermBase &queryTerm() const = 0;
     virtual const vespalib::string &attributeName() const = 0;
 
-    bool cmp(DocId docId, int32_t &weight) const { return onCmp(docId, weight); }
-    bool cmp(DocId docId) const { return onCmp(docId); }
+    int32_t find(DocId docId, int32_t elementId, int32_t &weight) const { return onCmp(docId, elementId, weight); }
+    int32_t find(DocId docId, int32_t elementId) const { return onCmp(docId, elementId); }
+    bool matches(DocId docId, int32_t &weight) const { return find(docId, 0, weight) >= 0; }
+    bool matches(DocId doc) const { return find(doc, 0) >= 0; }
 
 };
 
diff --git a/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.cpp b/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.cpp
index 068b7f4fa00..99865f6bd44 100644
--- a/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.cpp
+++ b/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.cpp
@@ -12,15 +12,14 @@ using search::QueryTermSimple;
 using search::fef::TermFieldMatchData;
 using search::queryeval::SearchIterator;
 
-namespace proton {
-namespace documentmetastore {
+namespace proton::documentmetastore {
 
 namespace {
 
 class GidAllSearchIterator : public AttributeIteratorBase
 {
 private:
-    virtual void
+    void
     doSeek(uint32_t docId) override
     {
         if (_store.validLidFast(docId)) {
@@ -28,7 +27,7 @@ private:
         }
     }
 
-    virtual void
+    void
     doUnpack(uint32_t docId) override
     {
         _matchData->reset(docId);
@@ -37,8 +36,7 @@ private:
 protected:
     const DocumentMetaStore & _store;
 public:
-    GidAllSearchIterator(TermFieldMatchData *matchData,
-                         const DocumentMetaStore &store)
+    GidAllSearchIterator(TermFieldMatchData *matchData, const DocumentMetaStore &store)
         : AttributeIteratorBase(matchData),
           _store(store)
     {
@@ -79,7 +77,7 @@ class GidSearchIterator : public GidAllSearchIterator
 private:
     const GlobalId & _gid;
 
-    virtual void
+    void
     doSeek(uint32_t docId) override
     {
         AttributeVector::DocId lid = 0;
@@ -90,9 +88,7 @@ private:
         }
     }
 public:
-    GidSearchIterator(TermFieldMatchData *matchData,
-                      const DocumentMetaStore &store,
-                      const GlobalId &gid)
+    GidSearchIterator(TermFieldMatchData *matchData, const DocumentMetaStore &store, const GlobalId &gid)
         : GidAllSearchIterator(matchData, store),
           _gid(gid)
     {
@@ -101,23 +97,16 @@ public:
 
 }
 
-bool
-SearchContext::onCmp(DocId docId, int32_t &weight) const
+int32_t
+SearchContext::onCmp(DocId, int32_t, int32_t &) const
 {
-    (void) docId;
-    (void) weight;
-    throw vespalib::IllegalStateException(
-            "The function is not implemented for documentmetastore::SearchContext");
-    return false;
+    throw vespalib::IllegalStateException("The function is not implemented for documentmetastore::SearchContext");
 }
 
-bool
-SearchContext::onCmp(DocId docId) const
+int32_t
+SearchContext::onCmp(DocId, int32_t ) const
 {
-    (void) docId;
-    throw vespalib::IllegalStateException(
-            "The function is not implemented for documentmetastore::SearchContext");
-    return false;
+    throw vespalib::IllegalStateException("The function is not implemented for documentmetastore::SearchContext");
 }
 
 unsigned int
@@ -127,15 +116,13 @@ SearchContext::approximateHits() const
 }
 
 SearchIterator::UP
-SearchContext::createIterator(TermFieldMatchData *matchData,
-                              bool strict)
+SearchContext::createIterator(TermFieldMatchData *matchData, bool strict)
 {
     return _isWord
-        ? SearchIterator::UP(new GidSearchIterator(matchData, getStore(), _gid))
+        ? std::make_unique<GidSearchIterator>(matchData, getStore(), _gid)
         : strict
-            ?  SearchIterator::UP(new GidStrictAllSearchIterator(matchData,
-                                      getStore()))
-            :  SearchIterator::UP(new GidAllSearchIterator(matchData, getStore()));
+            ?  std::make_unique<GidStrictAllSearchIterator>(matchData, getStore())
+            :  std::make_unique<GidAllSearchIterator>(matchData, getStore());
 }
 
 const DocumentMetaStore &
@@ -144,12 +131,10 @@ SearchContext::getStore() const
     return static_cast<const DocumentMetaStore &>(attribute());
 }
 
-SearchContext::SearchContext(QueryTermSimple::UP qTerm,
-                             const DocumentMetaStore &toBeSearched)
+SearchContext::SearchContext(QueryTermSimple::UP qTerm, const DocumentMetaStore &toBeSearched)
     : search::AttributeVector::SearchContext(toBeSearched),
       _isWord(qTerm->isWord())
 {
 }
 
 }
-}
diff --git a/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.h b/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.h
index afd09be43e9..6e1eaa468c9 100644
--- a/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.h
+++ b/searchcore/src/vespa/searchcore/proton/documentmetastore/search_context.h
@@ -6,8 +6,7 @@
 #include <vespa/searchlib/attribute/attributevector.h>
 #include "documentmetastore.h"
 
-namespace proton {
-namespace documentmetastore {
+namespace proton::documentmetastore {
 
 /**
  * Search context used to search the document meta store for all valid documents.
@@ -15,14 +14,14 @@ namespace documentmetastore {
 class SearchContext : public search::AttributeVector::SearchContext
 {
 private:
-    typedef search::AttributeVector::DocId DocId;
+    using DocId = search::AttributeVector::DocId;
 
     bool _isWord;
     document::GlobalId _gid;
 
     unsigned int approximateHits() const override;
-    bool onCmp(DocId docId, int32_t &weight) const override;
-    bool onCmp(DocId docId) const override;
+    int32_t onCmp(DocId docId, int32_t elemId, int32_t &weight) const override;
+    int32_t onCmp(DocId docId, int32_t elemId) const override;
 
     search::queryeval::SearchIterator::UP
     createIterator(search::fef::TermFieldMatchData *matchData, bool strict) override;
@@ -30,10 +29,7 @@ private:
     const DocumentMetaStore &getStore() const;
 
 public:
-    SearchContext(std::unique_ptr<search::QueryTermSimple> qTerm,
-                  const DocumentMetaStore &toBeSearched);
+    SearchContext(std::unique_ptr<search::QueryTermSimple> qTerm, const DocumentMetaStore &toBeSearched);
 };
 
-} // namespace documentmetastore
-} // namespace proton
-
+}
diff --git a/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp b/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp
index e8e16ffcc98..bb9d9960d08 100644
--- a/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp
+++ b/searchlib/src/tests/attribute/imported_search_context/imported_search_context_test.cpp
@@ -303,22 +303,22 @@ TEST_F("Strict iterator handles seek outside of LID space", ArrayValueFixture) {
 
 TEST_F("cmp() performs GID mapping and forwards to target attribute", SingleValueFixture) {
     auto ctx = f.create_context(word_term("5678"));
-    EXPECT_FALSE(ctx->cmp(DocId(2)));
-    EXPECT_TRUE(ctx->cmp(DocId(3)));
-    EXPECT_FALSE(ctx->cmp(DocId(4)));
-    EXPECT_TRUE(ctx->cmp(DocId(5)));
+    EXPECT_FALSE(ctx->matches(DocId(2)));
+    EXPECT_TRUE(ctx->matches(DocId(3)));
+    EXPECT_FALSE(ctx->matches(DocId(4)));
+    EXPECT_TRUE(ctx->matches(DocId(5)));
 }
 
 TEST_F("cmp(weight) performs GID mapping and forwards to target attribute", WsetValueFixture) {
     auto ctx = f.create_context(word_term("foo"));
     int32_t weight = 0;
-    EXPECT_FALSE(ctx->cmp(DocId(1), weight));
+    EXPECT_FALSE(ctx->matches(DocId(1), weight));
     EXPECT_EQUAL(0, weight); // Unchanged
 
-    EXPECT_TRUE(ctx->cmp(DocId(2), weight));
+    EXPECT_TRUE(ctx->matches(DocId(2), weight));
     EXPECT_EQUAL(-5, weight);
 
-    EXPECT_TRUE(ctx->cmp(DocId(6), weight));
+    EXPECT_TRUE(ctx->matches(DocId(6), weight));
     EXPECT_EQUAL(42, weight);
 }
 
diff --git a/searchlib/src/vespa/searchlib/attribute/attributeiterators.h b/searchlib/src/vespa/searchlib/attribute/attributeiterators.h
index febf7d101a9..e0fa06c5e84 100644
--- a/searchlib/src/vespa/searchlib/attribute/attributeiterators.h
+++ b/searchlib/src/vespa/searchlib/attribute/attributeiterators.h
@@ -82,7 +82,7 @@ protected:
 
 public:
     AttributeIteratorT(const SC &searchContext, fef::TermFieldMatchData *matchData);
-    bool seekFast(uint32_t docId) const { return _searchContext.cmp(docId); }
+    bool seekFast(uint32_t docId) const { return _searchContext.matches(docId); }
 };
 
 template <typename SC>
@@ -100,7 +100,7 @@ protected:
 
 public:
     FilterAttributeIteratorT(const SC &searchContext, fef::TermFieldMatchData *matchData);
-    bool seekFast(uint32_t docId) const { return _searchContext.cmp(docId); }
+    bool seekFast(uint32_t docId) const { return _searchContext.matches(docId); }
 };
 
 
diff --git a/searchlib/src/vespa/searchlib/attribute/attributeiterators.hpp b/searchlib/src/vespa/searchlib/attribute/attributeiterators.hpp
index fb47ad0cfcc..9b1e837beac 100644
--- a/searchlib/src/vespa/searchlib/attribute/attributeiterators.hpp
+++ b/searchlib/src/vespa/searchlib/attribute/attributeiterators.hpp
@@ -16,14 +16,14 @@ namespace search {
 template <typename SC>
 void
 AttributeIteratorBase::and_hits_into(const SC & sc, BitVector & result, uint32_t begin_id) const {
-    result.foreach_truebit([&](uint32_t key) { if ( ! sc.cmp(key)) { result.clearBit(key); }}, begin_id);
+    result.foreach_truebit([&](uint32_t key) { if ( ! sc.matches(key)) { result.clearBit(key); }}, begin_id);
     result.invalidateCachedCount();
 }
 
 template <typename SC>
 void
 AttributeIteratorBase::or_hits_into(const SC & sc, BitVector & result, uint32_t begin_id) const {
-    result.foreach_falsebit([&](uint32_t key) { if ( sc.cmp(key)) { result.setBit(key); }}, begin_id);
+    result.foreach_falsebit([&](uint32_t key) { if ( sc.matches(key)) { result.setBit(key); }}, begin_id);
     result.invalidateCachedCount();
 }
 
@@ -33,7 +33,7 @@ std::unique_ptr<BitVector>
 AttributeIteratorBase::get_hits(const SC & sc, uint32_t begin_id) const {
     BitVector::UP result = BitVector::create(begin_id, getEndId());
     for (uint32_t docId(std::max(begin_id, getDocId())); docId < getEndId(); docId++) {
-        if (sc.cmp(docId)) {
+        if (sc.matches(docId)) {
             result->setBit(docId);
         }
     }
@@ -338,7 +338,7 @@ AttributeIteratorT<SC>::doSeek(uint32_t docId)
 {
     if (isAtEnd(docId)) {
         setAtEnd();
-    } else if (_searchContext.cmp(docId, _weight)) {
+    } else if (_searchContext.matches(docId, _weight)) {
         setDocId(docId);
     }
 }
@@ -349,7 +349,7 @@ FilterAttributeIteratorT<SC>::doSeek(uint32_t docId)
 {
     if (isAtEnd(docId)) {
         setAtEnd();
-    } else if (_searchContext.cmp(docId)) {
+    } else if (_searchContext.matches(docId)) {
         setDocId(docId);
     }
 }
@@ -359,7 +359,7 @@ void
 AttributeIteratorStrict<SC>::doSeek(uint32_t docId)
 {
     for (uint32_t nextId = docId; !isAtEnd(nextId); ++nextId) {
-        if (_searchContext.cmp(nextId, _weight)) {
+        if (_searchContext.matches(nextId, _weight)) {
             setDocId(nextId);
             return;
         }
@@ -372,7 +372,7 @@ void
 FilterAttributeIteratorStrict<SC>::doSeek(uint32_t docId)
 {
     for (uint32_t nextId = docId; !isAtEnd(nextId); ++nextId) {
-        if (_searchContext.cmp(nextId)) {
+        if (_searchContext.matches(nextId)) {
             setDocId(nextId);
             return;
         }
diff --git a/searchlib/src/vespa/searchlib/attribute/imported_search_context.cpp b/searchlib/src/vespa/searchlib/attribute/imported_search_context.cpp
index bfcd7f29f29..c480eec5e88 100644
--- a/searchlib/src/vespa/searchlib/attribute/imported_search_context.cpp
+++ b/searchlib/src/vespa/searchlib/attribute/imported_search_context.cpp
@@ -44,8 +44,7 @@ ImportedSearchContext::ImportedSearchContext(
 
 }
 
-ImportedSearchContext::~ImportedSearchContext() {
-}
+ImportedSearchContext::~ImportedSearchContext() = default;
 
 unsigned int ImportedSearchContext::approximateHits() const {
     return _reference_attribute.getNumDocs();
diff --git a/searchlib/src/vespa/searchlib/attribute/imported_search_context.h b/searchlib/src/vespa/searchlib/attribute/imported_search_context.h
index f8b434d4c6c..9573139b91a 100644
--- a/searchlib/src/vespa/searchlib/attribute/imported_search_context.h
+++ b/searchlib/src/vespa/searchlib/attribute/imported_search_context.h
@@ -50,7 +50,7 @@ public:
                           const SearchContextParams& params,
                           const ImportedAttributeVector& imported_attribute,
                           const attribute::IAttributeVector &target_attribute);
-    ~ImportedSearchContext();
+    ~ImportedSearchContext() override;
 
 
     std::unique_ptr<queryeval::SearchIterator>
@@ -64,16 +64,16 @@ public:
 
     using DocId = IAttributeVector::DocId;
 
-    bool cmp(DocId docId, int32_t& weight) const {
-        return _target_search_context->cmp(getTargetLid(docId), weight);
+    int32_t find(DocId docId, int32_t elemId, int32_t& weight) const {
+        return _target_search_context->find(getTargetLid(docId), elemId, weight);
     }
 
-    bool cmp(DocId docId) const {
-        return _target_search_context->cmp(getTargetLid(docId));
+    int32_t find(DocId docId, int32_t elemId) const {
+        return _target_search_context->find(getTargetLid(docId), elemId);
     }
 
-    bool onCmp(uint32_t docId, int32_t &weight) const override { return cmp(docId, weight); }
-    bool onCmp(uint32_t docId) const override { return cmp(docId); }
+    int32_t onCmp(uint32_t docId, int32_t elemId, int32_t &weight) const override { return find(docId, elemId, weight); }
+    int32_t onCmp(uint32_t docId, int32_t elemId) const override { return find(docId, elemId); }
 
     const ReferenceAttribute& attribute() const noexcept { return _reference_attribute; }
 
diff --git a/searchlib/src/vespa/searchlib/attribute/multinumericattribute.h b/searchlib/src/vespa/searchlib/attribute/multinumericattribute.h
index 1e02e4d39b0..a03bc74a44a 100644
--- a/searchlib/src/vespa/searchlib/attribute/multinumericattribute.h
+++ b/searchlib/src/vespa/searchlib/attribute/multinumericattribute.h
@@ -71,12 +71,12 @@ public:
     private:
         const MultiValueNumericAttribute<B, M> & _toBeSearched;
 
-        bool onCmp(DocId docId, int32_t & weight) const override {
-            return cmp(docId, weight);
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override {
+            return find(docId, elemId, weight);
         }
 
-        bool onCmp(DocId docId) const override {
-            return cmp(docId);
+        int32_t onCmp(DocId docId, int32_t elemId) const override {
+            return find(docId, elemId);
         }
 
         bool valid() const override;
@@ -86,25 +86,25 @@ public:
 
         Int64Range getAsIntegerTerm() const override;
 
-        bool cmp(DocId doc, int32_t & weight) const {
+        int32_t find(DocId doc, int32_t elemId, int32_t & weight) const {
             MultiValueArrayRef values(_toBeSearched._mvMapping.get(doc));
-            for (const MultiValueType &mv : values) {
-                if (this->match(mv.value())) {
-                    weight = mv.weight();
-                    return true;
+            for (uint32_t i(elemId); i < values.size(); i++) {
+                if (this->match(values[i].value())) {
+                    weight = values[i].weight();
+                    return i;
                 }
             }
-            return false;
+            return -1;
         }
 
-        bool cmp(DocId doc) const {
+        int32_t find(DocId doc, int32_t elemId) const {
             MultiValueArrayRef values(_toBeSearched._mvMapping.get(doc));
-            for (const MultiValueType &mv : values) {
-                if (this->match(mv.value())) {
-                    return true;
+            for (uint32_t i(elemId); i < values.size(); i++) {
+                if (this->match(values[i].value())) {
+                    return i;
                 }
             }
-            return false;
+            return -1;
         }
 
         std::unique_ptr<queryeval::SearchIterator>
@@ -119,12 +119,12 @@ public:
     private:
         const MultiValueNumericAttribute<B, M> & _toBeSearched;
 
-        bool onCmp(DocId docId, int32_t & weight) const override {
-            return cmp(docId, weight);
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override {
+            return find(docId, elemId, weight);
         }
 
-        bool onCmp(DocId docId) const override {
-            return cmp(docId);
+        int32_t onCmp(DocId docId, int32_t elemId) const override {
+            return find(docId, elemId);
         }
 
     protected:
@@ -132,27 +132,31 @@ public:
 
     public:
         ArraySearchContext(std::unique_ptr<QueryTermSimple> qTerm, const NumericAttribute & toBeSearched);
-        bool cmp(DocId doc, int32_t & weight) const {
+        int32_t find(DocId doc, int32_t elemId, int32_t & weight) const {
             uint32_t hitCount = 0;
             MultiValueArrayRef values(_toBeSearched._mvMapping.get(doc));
-            for (const MultiValueType &mv : values) {
-                if (this->match(mv.value())) {
+            int32_t firstMatch = -1;
+            for (uint32_t i(elemId); i < values.size(); i++) {
+                if (this->match(values[i].value())) {
+                    if (firstMatch == -1) {
+                        firstMatch = i;
+                    }
                     hitCount++;
                 }
             }
             weight = hitCount;
 
-            return hitCount != 0;
+            return firstMatch;
         }
 
-        bool cmp(DocId doc) const {
+        int32_t find(DocId doc, int32_t elemId) const {
             MultiValueArrayRef values(_toBeSearched._mvMapping.get(doc));
-            for (const MultiValueType &mv : values) {
-                if (this->match(mv.value())) {
-                    return true;
+            for (uint32_t i(elemId); i < values.size(); i++) {
+                if (this->match(values[i].value())) {
+                    return i;
                 }
             }
-            return false;
+            return -1;
         }
 
         Int64Range getAsIntegerTerm() const override;
diff --git a/searchlib/src/vespa/searchlib/attribute/multinumericenumattribute.h b/searchlib/src/vespa/searchlib/attribute/multinumericenumattribute.h
index 66dbbfeb1da..35a81dafb51 100644
--- a/searchlib/src/vespa/searchlib/attribute/multinumericenumattribute.h
+++ b/searchlib/src/vespa/searchlib/attribute/multinumericenumattribute.h
@@ -52,12 +52,12 @@ protected:
     protected:
         const MultiValueNumericEnumAttribute<B, M> & _toBeSearched;
 
-        bool onCmp(DocId docId, int32_t & weight) const override {
-            return cmp(docId, weight);
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override {
+            return find(docId, elemId, weight);
         }
 
-        bool onCmp(DocId docId) const override {
-            return cmp(docId);
+        int32_t onCmp(DocId docId, int32_t elemId) const override {
+            return find(docId, elemId);
         }
 
         bool valid() const override { return this->isValid(); }
@@ -65,31 +65,31 @@ protected:
     public:
         SetSearchContext(QueryTermSimpleUP qTerm, const NumericAttribute & toBeSearched);
 
-        bool
-        cmp(DocId doc, int32_t & weight) const
+        int32_t
+        find(DocId doc, int32_t elemId, int32_t & weight) const
         {
             WeightedIndexArrayRef indices(_toBeSearched._mvMapping.get(doc));
-            for (const WeightedIndex &wi : indices) {
-                T v = _toBeSearched._enumStore.getValue(wi.value());
+            for (uint32_t i(elemId); i < indices.size(); i++) {
+                T v = _toBeSearched._enumStore.getValue(indices[i].value());
                 if (this->match(v)) {
-                    weight = wi.weight();
-                    return true;
+                    weight = indices[i].weight();
+                    return elemId;
                 }
             }
-            return false;
+            return -1;
         }
 
-        bool
-        cmp(DocId doc) const
+        int32_t
+        find(DocId doc, int32_t elemId) const
         {
             WeightedIndexArrayRef indices(_toBeSearched._mvMapping.get(doc));
-            for (const WeightedIndex &wi : indices) {
-                T v = _toBeSearched._enumStore.getValue(wi.value());
+            for (uint32_t i(elemId); i < indices.size(); i++) {
+                T v = _toBeSearched._enumStore.getValue(indices[i].value());
                 if (this->match(v)) {
-                    return true;
+                    return i;
                 }
             }
-            return false;
+            return -1;
         }
         Int64Range getAsIntegerTerm() const override;
 
@@ -105,12 +105,12 @@ protected:
     protected:
         const MultiValueNumericEnumAttribute<B, M> & _toBeSearched;
 
-        bool onCmp(DocId docId, int32_t & weight) const override {
-            return cmp(docId, weight);
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override {
+            return find(docId, elemId, weight);
         }
 
-        bool onCmp(DocId docId) const override {
-            return cmp(docId);
+        int32_t onCmp(DocId docId, int32_t elemId) const override {
+            return find(docId, elemId);
         }
 
         bool valid() const override { return this->isValid(); }
@@ -119,34 +119,38 @@ protected:
         ArraySearchContext(QueryTermSimpleUP qTerm, const NumericAttribute & toBeSearched);
         Int64Range getAsIntegerTerm() const override;
 
-        bool
-        cmp(DocId doc, int32_t & weight) const
+        int32_t
+        find(DocId doc, int32_t elemId, int32_t & weight) const
         {
             uint32_t hitCount = 0;
             WeightedIndexArrayRef indices(_toBeSearched._mvMapping.get(doc));
-            for (const WeightedIndex &wi : indices) {
-                T v = _toBeSearched._enumStore.getValue(wi.value());
+            int32_t firstMatch = -1;
+            for (uint32_t i(elemId); i < indices.size(); i++) {
+                T v = _toBeSearched._enumStore.getValue(indices[i].value());
                 if (this->match(v)) {
+                    if (firstMatch == -1) {
+                        firstMatch = i;
+                    }
                     hitCount++;
                 }
             }
             weight = hitCount;
 
-            return hitCount != 0;
+            return firstMatch;
         }
 
         bool
-        cmp(DocId doc) const
+        find(DocId doc, int32_t elemId) const
         {
             WeightedIndexArrayRef indices(_toBeSearched._mvMapping.get(doc));
-            for (const WeightedIndex &wi : indices) {
-                T v = _toBeSearched._enumStore.getValue(wi.value());
+            for (uint32_t i(elemId); i < indices.size(); i++) {
+                T v = _toBeSearched._enumStore.getValue(indices[i].value());
                 if (this->match(v)) {
-                    return true;
+                    return i;
                 }
             }
 
-            return false;
+            return -1;
         }
 
         std::unique_ptr<queryeval::SearchIterator>
diff --git a/searchlib/src/vespa/searchlib/attribute/multistringattribute.h b/searchlib/src/vespa/searchlib/attribute/multistringattribute.h
index 7edbcedcb2e..a03a2a02287 100644
--- a/searchlib/src/vespa/searchlib/attribute/multistringattribute.h
+++ b/searchlib/src/vespa/searchlib/attribute/multistringattribute.h
@@ -119,10 +119,10 @@ public:
         const MultiValueStringAttributeT<B, M> & myAttribute() const {
             return static_cast< const MultiValueStringAttributeT<B, M> & > (attribute());
         }
-        bool onCmp(DocId docId) const override;
+        int32_t onCmp(DocId docId, int32_t elemId) const override;
 
         template <typename Collector>
-        bool collectWeight(DocId doc, int32_t & weight, Collector & collector) const;
+        int32_t collectWeight(DocId doc, int32_t elemId, int32_t & weight, Collector & collector) const;
     };
 
     /*
@@ -134,7 +134,7 @@ public:
             StringImplSearchContext(std::move(qTerm), toBeSearched)
         { }
     protected:
-        bool onCmp(DocId docId, int32_t & weight) const override;
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override;
     };
 
     /*
@@ -146,7 +146,7 @@ public:
             StringImplSearchContext(std::move(qTerm), toBeSearched)
         { }
     protected:
-        bool onCmp(DocId docId, int32_t & weight) const override;
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override;
     };
 
     template <typename BT>
diff --git a/searchlib/src/vespa/searchlib/attribute/multistringattribute.hpp b/searchlib/src/vespa/searchlib/attribute/multistringattribute.hpp
index a68ac218784..20b9d2ed60b 100644
--- a/searchlib/src/vespa/searchlib/attribute/multistringattribute.hpp
+++ b/searchlib/src/vespa/searchlib/attribute/multistringattribute.hpp
@@ -62,47 +62,47 @@ private:
 }
 
 template <typename B, typename M>
-bool
-MultiValueStringAttributeT<B, M>::StringSetImplSearchContext::onCmp(DocId doc, int32_t & weight) const
+int32_t
+MultiValueStringAttributeT<B, M>::StringSetImplSearchContext::onCmp(DocId doc, int32_t elemId, int32_t & weight) const
 {
     StringAttribute::StringSearchContext::CollectWeight collector;
-    return this->collectWeight(doc, weight, collector);
+    return this->collectWeight(doc, elemId, weight, collector);
 }
 
 template <typename B, typename M>
-bool
-MultiValueStringAttributeT<B, M>::StringArrayImplSearchContext::onCmp(DocId doc, int32_t & weight) const
+int32_t
+MultiValueStringAttributeT<B, M>::StringArrayImplSearchContext::onCmp(DocId doc, int32_t elemId, int32_t & weight) const
 {
     StringAttribute::StringSearchContext::CollectHitCount collector;
-    return this->collectWeight(doc, weight, collector);
+    return this->collectWeight(doc, elemId, weight, collector);
 }
 
 template <typename B, typename M>
 template <typename Collector>
-bool
-MultiValueStringAttributeT<B, M>::StringImplSearchContext::collectWeight(DocId doc, int32_t & weight, Collector & collector) const
+int32_t
+MultiValueStringAttributeT<B, M>::StringImplSearchContext::collectWeight(DocId doc, int32_t elemId, int32_t & weight, Collector & collector) const
 {
     WeightedIndexArrayRef indices(myAttribute()._mvMapping.get(doc));
 
     EnumAccessor<typename B::EnumStore> accessor(myAttribute()._enumStore);
-    collectMatches(indices, accessor, collector);
+    int32_t foundElem = collectMatches(indices, elemId, accessor, collector);
     weight = collector.getWeight();
-    return collector.hasMatch();
+    return foundElem;
 }
 
 template <typename B, typename M>
-bool
-MultiValueStringAttributeT<B, M>::StringImplSearchContext::onCmp(DocId doc) const
+int32_t
+MultiValueStringAttributeT<B, M>::StringImplSearchContext::onCmp(DocId doc, int32_t elemId) const
 {
     const MultiValueStringAttributeT<B, M> & attr(static_cast< const MultiValueStringAttributeT<B, M> & > (attribute()));
     WeightedIndexArrayRef indices(attr._mvMapping.get(doc));
-    for (const WeightedIndex &wi : indices) {
-        if (isMatch(attr._enumStore.getValue(wi.value()))) {
-            return true;
+    for (uint32_t i(elemId); i < indices.size(); i++) {
+        if (isMatch(attr._enumStore.getValue(indices[i].value()))) {
+            return i;
         }
     }
 
-    return false;
+    return -1;
 }
 
 template <typename B, typename M>
diff --git a/searchlib/src/vespa/searchlib/attribute/singlenumericattribute.h b/searchlib/src/vespa/searchlib/attribute/singlenumericattribute.h
index 8edbf6cde59..de149564f21 100644
--- a/searchlib/src/vespa/searchlib/attribute/singlenumericattribute.h
+++ b/searchlib/src/vespa/searchlib/attribute/singlenumericattribute.h
@@ -41,27 +41,29 @@ private:
     private:
         const T * _data;
 
-        bool onCmp(DocId docId, int32_t & weight) const override {
-            return cmp(docId, weight);
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override {
+            return find(docId, elemId, weight);
         }
 
-        bool onCmp(DocId docId) const override {
-            return cmp(docId);
+        int32_t onCmp(DocId docId, int elemId) const override {
+            return find(docId, elemId);
         }
 
         bool valid() const override;
 
     public:
     SingleSearchContext(std::unique_ptr<QueryTermSimple> qTerm, const NumericAttribute & toBeSearched);
-        bool cmp(DocId docId, int32_t & weight) const {
+        int32_t find(DocId docId, int32_t elemId, int32_t & weight) const {
+            if ( elemId != 0) return -1;
             const T v = _data[docId];
             weight = 1;
-            return this->match(v);
+            return this->match(v) ? 0 : -1;
         }
 
-        bool cmp(DocId docId) const {
+        int32_t find(DocId docId, int elemId) const {
+            if ( elemId != 0) return -1;
             const T v = _data[docId];
-            return this->match(v);
+            return this->match(v) ? 0 : -1;
         }
 
         Int64Range getAsIntegerTerm() const override;
diff --git a/searchlib/src/vespa/searchlib/attribute/singlenumericenumattribute.h b/searchlib/src/vespa/searchlib/attribute/singlenumericenumattribute.h
index 7dca10e83e4..f10a6f0f35a 100644
--- a/searchlib/src/vespa/searchlib/attribute/singlenumericenumattribute.h
+++ b/searchlib/src/vespa/searchlib/attribute/singlenumericenumattribute.h
@@ -58,12 +58,12 @@ protected:
     protected:
         const SingleValueNumericEnumAttribute<B> & _toBeSearched;
 
-        bool onCmp(DocId docId, int32_t & weight) const override {
-            return cmp(docId, weight);
+        int32_t onCmp(DocId docId, int32_t elemId, int32_t & weight) const override {
+            return find(docId, elemId, weight);
         }
 
-        bool onCmp(DocId docId) const override {
-            return cmp(docId);
+        int32_t onCmp(DocId docId, int32_t elemId) const override {
+            return find(docId, elemId);
         }
         bool valid() const override;
 
@@ -72,15 +72,17 @@ protected:
 
         Int64Range getAsIntegerTerm() const override;
 
-        bool cmp(DocId docId, int32_t & weight) const {
+        int32_t find(DocId docId, int32_t elemId, int32_t & weight) const {
+            if ( elemId != 0) return -1;
             T v = _toBeSearched._enumStore.getValue(_toBeSearched.getEnumIndex(docId));
             weight = 1;
-            return this->match(v);
+            return this->match(v) ? 0 : -1;
         }
 
-        bool cmp(DocId docId) const {
+        int32_t find(DocId docId, int32_t elemId) const {
+            if ( elemId != 0) return -1;
             T v = _toBeSearched._enumStore.getValue(_toBeSearched.getEnumIndex(docId));
-            return this->match(v);
+            return this->match(v) ? 0 : -1;
         }
 
         std::unique_ptr<queryeval::SearchIterator>
diff --git a/searchlib/src/vespa/searchlib/attribute/singlesmallnumericattribute.h b/searchlib/src/vespa/searchlib/attribute/singlesmallnumericattribute.h
index 9320e248160..2087f74d104 100644
--- a/searchlib/src/vespa/searchlib/attribute/singlesmallnumericattribute.h
+++ b/searchlib/src/vespa/searchlib/attribute/singlesmallnumericattribute.h
@@ -67,12 +67,12 @@ public:
         uint32_t _valueShiftMask;
         uint32_t _wordShift;
 
-        bool onCmp(DocId docId, int32_t & weight) const override {
-            return cmp(docId, weight);
+        int32_t onCmp(DocId docId, int32_t elementId, int32_t & weight) const override {
+            return cmp(docId, elementId, weight);
         }
 
-        bool onCmp(DocId docId) const override {
-            return cmp(docId);
+        int32_t onCmp(DocId docId, int32_t elementId) const override {
+            return cmp(docId, elementId);
         }
 
         bool valid() const override;
@@ -80,19 +80,21 @@ public:
     public:
         SingleSearchContext(std::unique_ptr<QueryTermSimple> qTerm, const NumericAttribute & toBeSearched);
 
-        bool cmp(DocId docId, int32_t & weight) const {
+        int32_t cmp(DocId docId, int32_t elemId, int32_t & weight) const {
+            if ( elemId != 0) return -1;
             const Word &word = _wordData[docId >> _wordShift];
             uint32_t valueShift = (docId & _valueShiftMask) << _valueShiftShift;
             T v = (word >> valueShift) & _valueMask;
             weight = 1;
-            return match(v);
+            return match(v) ? 0 : -1;
         }
 
-        bool cmp(DocId docId) const {
+        int32_t cmp(DocId docId, int32_t elemId) const {
+            if ( elemId != 0) return -1;
             const Word &word = _wordData[docId >> _wordShift];
             uint32_t valueShift = (docId & _valueShiftMask) << _valueShiftShift;
             T v = (word >> valueShift) & _valueMask;
-            return match(v);
+            return match(v) ? 0 : -1;
         }
 
         Int64Range getAsIntegerTerm() const override;
@@ -101,14 +103,10 @@ public:
         createFilterIterator(fef::TermFieldMatchData * matchData, bool strict) override;
     };
 
-    SingleValueSmallNumericAttribute(const vespalib::string & baseFileName,
-                                     const Config &c,
-                                     Word valueMask,
-                                     uint32_t valueShiftShift,
-                                     uint32_t valueShiftMask,
-                                     uint32_t wordShift);
+    SingleValueSmallNumericAttribute(const vespalib::string & baseFileName, const Config &c, Word valueMask,
+                                     uint32_t valueShiftShift, uint32_t valueShiftMask, uint32_t wordShift);
 
-    ~SingleValueSmallNumericAttribute();
+    ~SingleValueSmallNumericAttribute() override;
 
     uint32_t getValueCount(DocId doc) const override {
         if (doc >= B::getNumDocs()) {
@@ -125,7 +123,8 @@ public:
     bool onLoad() override;
     void onSave(IAttributeSaveTarget &saveTarget) override;
 
-    SearchContext::UP getSearch(std::unique_ptr<QueryTermSimple> term, const attribute::SearchContextParams & params) const override;
+    SearchContext::UP
+    getSearch(std::unique_ptr<QueryTermSimple> term, const attribute::SearchContextParams & params) const override;
 
     T getFast(DocId doc) const {
         const Word &word = _wordData[doc >> _wordShift];
diff --git a/searchlib/src/vespa/searchlib/attribute/singlestringattribute.h b/searchlib/src/vespa/searchlib/attribute/singlestringattribute.h
index 227c1d0667c..8d9fd79717c 100644
--- a/searchlib/src/vespa/searchlib/attribute/singlestringattribute.h
+++ b/searchlib/src/vespa/searchlib/attribute/singlestringattribute.h
@@ -89,14 +89,15 @@ public:
             StringSearchContext(std::move(qTerm), toBeSearched)
         { }
     protected:
-        bool onCmp(DocId doc, int32_t & weight) const override {
+        int32_t onCmp(DocId doc, int32_t elemId, int32_t & weight) const override {
             weight = 1;
-            return onCmp(doc);
+            return onCmp(doc, elemId);
         }
 
-        bool onCmp(DocId doc) const override {
+        int32_t onCmp(DocId doc, int32_t elemId) const override {
+            if ( elemId != 0) return -1;
             const SingleValueStringAttributeT<B> & attr(static_cast<const SingleValueStringAttributeT<B> &>(attribute()));
-            return isMatch(attr._enumStore.getValue(attr._enumIndices[doc]));
+            return isMatch(attr._enumStore.getValue(attr._enumIndices[doc])) ? 0 : -1;
         }
 
     };
diff --git a/searchlib/src/vespa/searchlib/attribute/stringbase.cpp b/searchlib/src/vespa/searchlib/attribute/stringbase.cpp
index 5ba936b5f52..3e31c9ca2fa 100644
--- a/searchlib/src/vespa/searchlib/attribute/stringbase.cpp
+++ b/searchlib/src/vespa/searchlib/attribute/stringbase.cpp
@@ -273,31 +273,31 @@ public:
 
 }
 
-bool
-StringAttribute::StringSearchContext::onCmp(DocId docId, int32_t & weight) const
+int32_t
+StringAttribute::StringSearchContext::onCmp(DocId docId, int32_t elemId, int32_t & weight) const
 {
     WeightedConstChar * buffer = getBuffer();
     uint32_t valueCount = attribute().get(docId, buffer, _bufferLen);
 
     CollectWeight collector;
     DirectAccessor accessor;
-    collectMatches(vespalib::ConstArrayRef<WeightedConstChar>(buffer, std::min(valueCount, _bufferLen)), accessor, collector);
+    int32_t foundElem = collectMatches(vespalib::ConstArrayRef<WeightedConstChar>(buffer, std::min(valueCount, _bufferLen)), elemId, accessor, collector);
     weight = collector.getWeight();
-    return collector.hasMatch();
+    return foundElem;
 }
 
-bool
-StringAttribute::StringSearchContext::onCmp(DocId docId) const
+int32_t
+StringAttribute::StringSearchContext::onCmp(DocId docId, int32_t elemId) const
 {
     WeightedConstChar * buffer = getBuffer();
     uint32_t valueCount = attribute().get(docId, buffer, _bufferLen);
-    for (uint32_t i = 0, m = std::min(valueCount, _bufferLen); (i < m); i++) {
+    for (uint32_t i = elemId, m = std::min(valueCount, _bufferLen); (i < m); i++) {
         if (isMatch(buffer[i].getValue())) {
-            return true;
+            return i;
         }
     }
 
-    return false;
+    return -1;
 }
 
 bool StringAttribute::applyWeight(DocId doc, const FieldValue & fv, const ArithmeticValueUpdate & wAdjust)
diff --git a/searchlib/src/vespa/searchlib/attribute/stringbase.h b/searchlib/src/vespa/searchlib/attribute/stringbase.h
index 5e0847f3039..4176d172ab0 100644
--- a/searchlib/src/vespa/searchlib/attribute/stringbase.h
+++ b/searchlib/src/vespa/searchlib/attribute/stringbase.h
@@ -96,7 +96,7 @@ private:
     class StringSearchContext : public SearchContext {
     public:
         StringSearchContext(QueryTermSimpleUP qTerm, const StringAttribute & toBeSearched);
-        virtual ~StringSearchContext();
+        ~StringSearchContext() override;
     private:
         bool                        _isPrefix;
         bool                        _isRegex;
@@ -147,17 +147,22 @@ private:
         };
 
         template<typename WeightedT, typename Accessor, typename Collector>
-        void collectMatches(vespalib::ConstArrayRef<WeightedT> w, const Accessor & ac, Collector & collector) const {
-            for (const WeightedT &wRef : w) {
-                if (isMatch(ac.get(wRef.value()))) {
-                    collector.addWeight(wRef.weight());
+        int32_t collectMatches(vespalib::ConstArrayRef<WeightedT> w, int32_t elemId, const Accessor & ac, Collector & collector) const {
+            int firstMatch = -1;
+            for (uint32_t i(elemId); i < w.size(); i++) {
+                if (isMatch(ac.get(w[i].value()))) {
+                    collector.addWeight(w[i].weight());
+                    if (firstMatch == -1) {
+                        firstMatch = i;
+                    }
                 }
             }
+            return firstMatch;
         }
 
 
-        bool onCmp(DocId docId, int32_t & weight) const override;
-        bool onCmp(DocId docId) const override;
+        int32_t onCmp(DocId docId, int32_t elementId, int32_t & weight) const override;
+        int32_t onCmp(DocId docId, int32_t elementId) const override;
 
         bool isPrefix() const { return _isPrefix; }
         bool  isRegex() const { return _isRegex; }
@@ -166,7 +171,7 @@ private:
         const vespalib::Regexp * getRegex() const { return _regex.get(); }
     private:
         WeightedConstChar * getBuffer() const {
-            if (_buffer == NULL) {
+            if (_buffer == nullptr) {
                 _buffer = new WeightedConstChar[_bufferLen];
             }
             return _buffer;