Remove the hack

dbms/src/Storages/DeltaMerge/Index/VectorIndexCache.h

@@ -24,6 +24,11 @@
 #include <thread>
 #include <unordered_set>
 
+namespace DB::DM::tests
+{
+class VectorIndexTestUtils;
+}
+
 namespace DB::DM
 {
 
@@ -44,18 +49,16 @@ class VectorIndexCache
     std::condition_variable shutdown_cv;
     std::mutex shutdown_mu;
 
-#ifdef DBMS_PUBLIC_GTEST
-public:
-#else
 private:
-#endif
+    friend class ::DB::DM::tests::VectorIndexTestUtils;
 
     // Drop the in-memory Vector Index if the on-disk file is deleted.
     // mmaped file could be unmmaped so that disk space can be reclaimed.
     size_t cleanOutdatedCacheEntries();
 
     void cleanOutdatedLoop();
 
+    // TODO(vector-index): Use task on BackgroundProcessingPool instead of a raw thread
     std::thread cleaner_thread;
 
 public:

dbms/src/Storages/DeltaMerge/Index/VectorIndexHNSW/Index.cpp

@@ -162,6 +162,7 @@ std::vector<VectorIndexBuilder::Key> VectorIndexHNSWViewer::search(
     std::atomic<size_t> discarded_nodes = 0;
     std::atomic<bool> has_exception_in_search = false;
 
+    // The non-valid rows should be discarded by this lambda
     auto predicate = [&](typename USearchImplType::member_cref_t const & member) {
         // Must catch exceptions in the predicate, because search runs on other threads.
         try
@@ -180,7 +181,7 @@ std::vector<VectorIndexBuilder::Key> VectorIndexHNSWViewer::search(
         }
     };
 
-    // TODO: Support efSearch.
+    // TODO(vector-index): Support efSearch.
     auto result = index.search( //
         reinterpret_cast<const Float32 *>(query_info->ref_vec_f32().data() + sizeof(UInt32)),
         query_info->top_k(),

dbms/src/Storages/DeltaMerge/tests/gtest_dm_vector_index.cpp

@@ -95,6 +95,11 @@ class VectorIndexTestUtils
         // When used in read, no need to assign vector_index.
         return ColumnDefine(vec_column_id, vec_column_name, tests::typeFromString("Array(Float32)"));
     }
+
+    static size_t cleanVectorCacheEntries(const std::shared_ptr<VectorIndexCache> & cache)
+    {
+        return cache->cleanOutdatedCacheEntries();
+    }
 };
 
 class VectorIndexDMFileTest
@@ -1638,7 +1643,8 @@ try
     {
         // We should be able to clear something from the vector index cache.
         auto vec_cache = TiFlashTestEnv::getGlobalContext().getVectorIndexCache();
-        ASSERT_EQ(1, vec_cache->cleanOutdatedCacheEntries());
+        ASSERT_NE(vec_cache, nullptr);
+        ASSERT_EQ(1, cleanVectorCacheEntries(vec_cache));
     }
     {
         // When cache is evicted (and memory cache is dropped), the query should be fine.
@@ -1777,7 +1783,8 @@ try
     {
         // We should be able to clear something from the vector index cache.
         auto vec_cache = TiFlashTestEnv::getGlobalContext().getVectorIndexCache();
-        ASSERT_EQ(1, vec_cache->cleanOutdatedCacheEntries());
+        ASSERT_NE(vec_cache, nullptr);
+        ASSERT_EQ(1, cleanVectorCacheEntries(vec_cache));
     }
     {
         // Query should be fine.