Handle repeating facet values in value facet index.

include/facet_index.h

@@ -163,4 +163,8 @@ public:
                             std::list<facet_count_t>::iterator& curr);
 
     bool facet_value_exists(const std::string& field_name, const std::string& fvalue);
+
+    size_t facet_val_num_ids(const std::string& field_name, const std::string& fvalue);
+
+    size_t facet_node_count(const std::string& field_name, const std::string& fvalue);
 };

include/index.h

@@ -652,6 +652,8 @@ public:
 
     const spp::sparse_hash_map<std::string, hnsw_index_t*>& _get_vector_index() const;
 
+    facet_index_t* _get_facet_index() const;
+
     static int get_bounded_typo_cost(const size_t max_cost, const size_t token_len,
                                      size_t min_len_1typo, size_t min_len_2typo);
 

src/facet_index.cpp

@@ -59,9 +59,8 @@ void facet_index_t::insert(const std::string& field_name,std::unordered_map<face
                 fis.facet_id = facet_id;
 
                 if(facet_index.has_value_index) {
-                    auto new_count = seq_ids.size();
                     fis.seq_ids = ids_t::create(seq_ids);
-
+                    auto new_count = ids_t::num_ids(fis.seq_ids);
                     auto& count_map = facet_index.count_map;
                     auto count_map_it = count_map.lower_bound(new_count);
 
@@ -227,7 +226,7 @@ void facet_index_t::remove(const std::string& field_name, const uint32_t seq_id)
                 auto& count_list = facet_field_it->second.counts;
                 auto curr = facet_ids_seq_ids->second.facet_count_it;
                 auto old_count = curr->count;
-                curr->count--;
+                curr->count = ids_t::num_ids(ids);
                 auto new_count = curr->count;
 
                 // move the node lower in the count list
@@ -496,3 +495,30 @@ bool facet_index_t::facet_value_exists(const std::string& field_name, const std:
     const auto& facet_index = facet_field_map_it->second;
     return facet_index.fvalue_seq_ids.find(fvalue) != facet_index.fvalue_seq_ids.end();
 }
+
+size_t facet_index_t::facet_val_num_ids(const string &field_name, const string &fvalue) {
+    const auto facet_field_map_it = facet_field_map.find(field_name);
+    if(facet_field_map_it == facet_field_map.end()) {
+        return 0;
+    }
+
+    if(facet_field_map_it->second.fvalue_seq_ids.count(fvalue) == 0) {
+        return 0;
+    }
+
+    return ids_t::num_ids(facet_field_map_it->second.fvalue_seq_ids[fvalue].seq_ids);
+}
+
+size_t facet_index_t::facet_node_count(const string &field_name, const string &fvalue) {
+    const auto facet_field_map_it = facet_field_map.find(field_name);
+    if(facet_field_map_it == facet_field_map.end()) {
+        return 0;
+    }
+
+    if(facet_field_map_it->second.fvalue_seq_ids.count(fvalue) == 0) {
+        return 0;
+    }
+
+    return facet_field_map_it->second.fvalue_seq_ids[fvalue].facet_count_it->count;
+}
+

src/index.cpp

@@ -6525,6 +6525,10 @@ const spp::sparse_hash_map<std::string, hnsw_index_t*>& Index::_get_vector_index
     return vector_index;
 }
 
+facet_index_t* Index::_get_facet_index() const {
+    return facet_index_v4;
+}
+
 void Index::refresh_schemas(const std::vector<field>& new_fields, const std::vector<field>& del_fields) {
     std::unique_lock lock(mutex);
 

test/collection_optimized_faceting_test.cpp

@@ -608,6 +608,43 @@ TEST_F(CollectionOptimizedFacetingTest, FacetCountsFloatPrecision) {
     collectionManager.drop_collection("coll1");
 }
 
+TEST_F(CollectionOptimizedFacetingTest, FacetDeleteRepeatingValuesInArray) {
+    Collection *coll1;
+
+    std::vector<field> fields = {field("tags", field_types::STRING_ARRAY, true)};
+
+    std::vector<sort_by> sort_fields = {};
+
+    coll1 = collectionManager.get_collection("coll1").get();
+    if (coll1 == nullptr) {
+        coll1 = collectionManager.create_collection("coll1", 4, fields).get();
+    }
+
+    nlohmann::json doc;
+    doc["id"] = "0";
+    doc["tags"] = {"alpha", "beta", "alpha"};
+
+    coll1->add(doc.dump());
+
+    auto findex = coll1->_get_index()->_get_facet_index();
+    ASSERT_EQ(1, findex->facet_val_num_ids("tags", "alpha"));
+    ASSERT_EQ(1, findex->facet_node_count("tags", "alpha"));
+
+    doc["id"] = "1";
+    doc["tags"] = {"alpha"};
+    coll1->add(doc.dump());
+
+    coll1->remove("0");
+
+    ASSERT_EQ(1, findex->facet_val_num_ids("tags", "alpha"));
+    ASSERT_EQ(1, findex->facet_node_count("tags", "alpha"));
+
+    ASSERT_EQ(0, findex->facet_val_num_ids("tags", "beta"));
+    ASSERT_EQ(0, findex->facet_node_count("tags", "beta"));
+
+    collectionManager.drop_collection("coll1");
+}
+
 TEST_F(CollectionOptimizedFacetingTest, FacetStatOnFloatFields) {
     Collection *coll_float_fields;