enhance: mark sparse inverted index as mmap-able (#33281)

issue: #29419

Signed-off-by: Buqian Zheng <zhengbuqian@gmail.com>

internal/core/src/index/Index.h

@@ -81,7 +81,10 @@ class IndexBase {
                index_type_ == knowhere::IndexEnum::INDEX_FAISS_IVFSQ8 ||
                index_type_ == knowhere::IndexEnum::INDEX_FAISS_BIN_IVFFLAT ||
                index_type_ == knowhere::IndexEnum::INDEX_FAISS_IDMAP ||
-               index_type_ == knowhere::IndexEnum::INDEX_FAISS_BIN_IDMAP;
+               index_type_ == knowhere::IndexEnum::INDEX_FAISS_BIN_IDMAP ||
+               index_type_ ==
+                   knowhere::IndexEnum::INDEX_SPARSE_INVERTED_INDEX ||
+               index_type_ == knowhere::IndexEnum::INDEX_SPARSE_WAND;
     }
 
     const IndexType&

internal/core/unittest/test_indexing.cpp

@@ -570,7 +570,7 @@ TEST_P(IndexTest, Mmap) {
     load_conf["mmap_filepath"] = "mmap/test_index_mmap_" + index_type;
     vec_index->Load(milvus::tracer::TraceContext{}, load_conf);
     EXPECT_EQ(vec_index->Count(), NB);
-    EXPECT_EQ(vec_index->GetDim(), DIM);
+    EXPECT_EQ(vec_index->GetDim(), is_sparse ? kTestSparseDim : DIM);
 
     milvus::SearchInfo search_info;
     search_info.topk_ = K;

internal/core/unittest/test_utils/DataGen.h

@@ -259,6 +259,18 @@ GenerateRandomSparseFloatVector(size_t rows,
 
     std::vector<std::map<int32_t, float>> data(rows);
 
+    // ensure the actual dim of the entire generated dataset is cols.
+    data[0][cols - 1] = real_distrib(rng);
+    --num_elements;
+
+    // Ensure each row has at least one non-zero value
+    for (size_t i = 0; i < rows; ++i) {
+        auto col = col_distrib(rng);
+        float val = real_distrib(rng);
+        data[i][col] = val;
+    }
+    num_elements -= rows;
+
     for (int32_t i = 0; i < num_elements; ++i) {
         auto row = row_distrib(rng);
         while (data[row].size() == (size_t)cols) {

pkg/util/indexparamcheck/index_type.go

@@ -57,7 +57,9 @@ func IsMmapSupported(indexType IndexType) bool {
 		indexType == IndexFaissBinIDMap ||
 		indexType == IndexFaissBinIvfFlat ||
 		indexType == IndexHNSW ||
-		indexType == IndexScaNN
+		indexType == IndexScaNN ||
+		indexType == IndexSparseInverted ||
+		indexType == IndexSparseWand
 }
 
 func IsDiskIndex(indexType IndexType) bool {