feat: vector field raw data to mmap by default (#41975)

issue: https://github.com/milvus-io/milvus/issues/41435

should address https://github.com/milvus-io/milvus/issues/41774

this PR also: 
* added caching layer memory overhead metric
* re-enable TextMatch.GrowingLoadData test

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

configs/milvus.yaml

@@ -464,7 +464,7 @@ queryNode:
     memoryLimit: 2147483648 # Deprecated: 2 GB, 2 * 1024 *1024 *1024
     readAheadPolicy: willneed # The read ahead policy of chunk cache, options: `normal, random, sequential, willneed, dontneed`
   mmap:
-    vectorField: false # Enable mmap for loading vector data
+    vectorField: true # Enable mmap for loading vector data
     vectorIndex: false # Enable mmap for loading vector index
     scalarField: false # Enable mmap for loading scalar data
     scalarIndex: false # Enable mmap for loading scalar index

internal/core/src/cachinglayer/CacheSlot.h

@@ -62,6 +62,8 @@ class CacheSlot final : public std::enable_shared_from_this<CacheSlot<CellT>> {
             .Increment();
         internal::cache_cell_count(translator_->meta()->storage_type)
             .Increment(translator_->num_cells());
+        internal::cache_memory_overhead_bytes(translator_->meta()->storage_type)
+            .Increment(memory_overhead());
     }
 
     CacheSlot(const CacheSlot&) = delete;
@@ -207,6 +209,8 @@ class CacheSlot final : public std::enable_shared_from_this<CacheSlot<CellT>> {
             .Decrement();
         internal::cache_cell_count(translator_->meta()->storage_type)
             .Decrement(translator_->num_cells());
+        internal::cache_memory_overhead_bytes(translator_->meta()->storage_type)
+            .Decrement(memory_overhead());
     }
 
  private:
@@ -365,6 +369,12 @@ class CacheSlot final : public std::enable_shared_from_this<CacheSlot<CellT>> {
         std::unique_ptr<CellT> cell_{nullptr};
         std::chrono::steady_clock::time_point life_start_{};
     };
+
+    size_t
+    memory_overhead() const {
+        return sizeof(*this) + cells_.size() * sizeof(CacheCell);
+    }
+
     const std::unique_ptr<Translator<CellT>> translator_;
     // Each CacheCell's cid_t is its index in vector
     // Once initialized, cells_ should never be resized.

internal/core/src/cachinglayer/lrucache/ListNode.h

@@ -79,7 +79,7 @@ class ListNode {
     bool
     manual_evict();
 
-    // TODO(tiered storage 1): pin on ERROR should re-trigger loading.
+    // TODO(tiered storage 2): pin on ERROR should re-trigger loading.
     // NOT_LOADED ---> LOADING ---> ERROR
     //      ^            |
     //      |            v

internal/core/src/monitor/prometheus_client.h

@@ -222,7 +222,6 @@ DECLARE_PROMETHEUS_COUNTER(internal_cache_load_count_fail_memory);
 DECLARE_PROMETHEUS_COUNTER(internal_cache_load_count_fail_disk);
 DECLARE_PROMETHEUS_COUNTER(internal_cache_load_count_fail_mixed);
 
-// TODO(tiered storage 1): not added
 DECLARE_PROMETHEUS_GAUGE_FAMILY(internal_cache_memory_overhead_bytes);
 DECLARE_PROMETHEUS_GAUGE(internal_cache_memory_overhead_bytes_memory);
 DECLARE_PROMETHEUS_GAUGE(internal_cache_memory_overhead_bytes_disk);

internal/core/src/segcore/storagev2translator/GroupChunkTranslator.cpp

@@ -155,8 +155,6 @@ GroupChunkTranslator::get_cells(const std::vector<cachinglayer::cid_t>& cids) {
         std::make_unique<ParallelDegreeSplitStrategy>(parallel_degree);
 
     auto& pool = ThreadPools::GetThreadPool(milvus::ThreadPoolPriority::MIDDLE);
-    auto fs = milvus_storage::ArrowFileSystemSingleton::GetInstance()
-                  .GetArrowFileSystem();
 
     auto load_future = pool.Submit([&]() {
         return LoadWithStrategy(insert_files_,

internal/core/unittest/test_exec.cpp

@@ -163,7 +163,6 @@ TEST_P(TaskTest, CallExprEmpty) {
     EXPECT_EQ(num_rows, num_rows_);
 }
 
-// TODO(tiered storage 1): this is slower due to the overhead of RawAt.
 TEST_P(TaskTest, UnaryExpr) {
     ::milvus::proto::plan::GenericValue value;
     value.set_int64_val(-1);

internal/core/unittest/test_text_match.cpp

@@ -951,9 +951,8 @@ TEST(TextMatch, SealedJieBaNullable) {
     }
 }
 
-// TODO(tiered storage 1): this also fails on master branch.
 // Test that growing segment loading flushed binlogs will build text match index.
-TEST(TextMatch, DISABLED_GrowingLoadData) {
+TEST(TextMatch, GrowingLoadData) {
     int64_t N = 7;
     auto schema = GenTestSchema({}, true);
     schema->AddField(

pkg/util/paramtable/component_param.go

@@ -3233,7 +3233,7 @@ This defaults to true, indicating that Milvus creates temporary index for growin
 	p.MmapVectorField = ParamItem{
 		Key:          "queryNode.mmap.vectorField",
 		Version:      "2.4.7",
-		DefaultValue: "false",
+		DefaultValue: "true",
 		Formatter: func(originValue string) string {
 			if p.MmapEnabled.GetAsBool() {
 				return "true"