enhance: Use a separate mmap config for chunk cache (#36276)

issue: https://github.com/milvus-io/milvus/issues/35273

Signed-off-by: bigsheeper <yihao.dai@zilliz.com>

configs/milvus.yaml

@@ -412,6 +412,7 @@ queryNode:
     vectorIndex: false # Enable mmap for loading vector index
     scalarField: false # Enable mmap for loading scalar data
     scalarIndex: false # Enable mmap for loading scalar index
+    chunkCache: true # Enable mmap for chunk cache (raw vector retrieving).
     # Enable memory mapping (mmap) to optimize the handling of growing raw data. 
     # By activating this feature, the memory overhead associated with newly added or modified data will be significantly minimized. 
     # However, this optimization may come at the cost of a slight decrease in query latency for the affected data segments.

internal/querynodev2/segments/segment.go

@@ -1172,7 +1172,8 @@ func (s *LocalSegment) LoadIndex(ctx context.Context, indexInfo *querypb.FieldIn
 	}
 
 	// 4.
-	s.WarmupChunkCache(ctx, indexInfo.GetFieldID(), isDataMmapEnable(fieldSchema))
+	mmapChunkCache := paramtable.Get().QueryNodeCfg.MmapChunkCache.GetAsBool()
+	s.WarmupChunkCache(ctx, indexInfo.GetFieldID(), mmapChunkCache)
 	warmupChunkCacheSpan := tr.RecordSpan()
 	log.Info("Finish loading index",
 		zap.Duration("newLoadIndexInfoSpan", newLoadIndexInfoSpan),

internal/querynodev2/server.go

@@ -376,8 +376,9 @@ func (node *QueryNode) Start() error {
 		growingmmapEnable := paramtable.Get().QueryNodeCfg.GrowingMmapEnabled.GetAsBool()
 		mmapVectorIndex := paramtable.Get().QueryNodeCfg.MmapVectorIndex.GetAsBool()
 		mmapVectorField := paramtable.Get().QueryNodeCfg.MmapVectorField.GetAsBool()
-		mmapScarlarIndex := paramtable.Get().QueryNodeCfg.MmapScalarIndex.GetAsBool()
+		mmapScalarIndex := paramtable.Get().QueryNodeCfg.MmapScalarIndex.GetAsBool()
-		mmapScarlarField := paramtable.Get().QueryNodeCfg.MmapScalarField.GetAsBool()
+		mmapScalarField := paramtable.Get().QueryNodeCfg.MmapScalarField.GetAsBool()
+		mmapChunkCache := paramtable.Get().QueryNodeCfg.MmapChunkCache.GetAsBool()
 
 		node.UpdateStateCode(commonpb.StateCode_Healthy)
 
@@ -389,8 +390,9 @@ func (node *QueryNode) Start() error {
 			zap.Bool("growingmmapEnable", growingmmapEnable),
 			zap.Bool("mmapVectorIndex", mmapVectorIndex),
 			zap.Bool("mmapVectorField", mmapVectorField),
-			zap.Bool("mmapScarlarIndex", mmapScarlarIndex),
+			zap.Bool("mmapScalarIndex", mmapScalarIndex),
-			zap.Bool("mmapScarlarField", mmapScarlarField),
+			zap.Bool("mmapScalarField", mmapScalarField),
+			zap.Bool("mmapChunkCache", mmapChunkCache),
 		)
 	})
 

pkg/util/paramtable/component_param.go

@@ -2337,6 +2337,7 @@ type queryNodeConfig struct {
 	MmapVectorIndex                     ParamItem `refreshable:"false"`
 	MmapScalarField                     ParamItem `refreshable:"false"`
 	MmapScalarIndex                     ParamItem `refreshable:"false"`
+	MmapChunkCache                      ParamItem `refreshable:"false"`
 	GrowingMmapEnabled                  ParamItem `refreshable:"false"`
 	FixedFileSizeForMmapManager         ParamItem `refreshable:"false"`
 	MaxMmapDiskPercentageForMmapManager ParamItem `refreshable:"false"`
@@ -2663,6 +2664,15 @@ This defaults to true, indicating that Milvus creates temporary index for growin
 	}
 	p.MmapScalarIndex.Init(base.mgr)
 
+	p.MmapChunkCache = ParamItem{
+		Key:          "queryNode.mmap.chunkCache",
+		Version:      "2.4.12",
+		DefaultValue: "true",
+		Doc:          "Enable mmap for chunk cache (raw vector retrieving).",
+		Export:       true,
+	}
+	p.MmapChunkCache.Init(base.mgr)
+
 	p.GrowingMmapEnabled = ParamItem{
 		Key:          "queryNode.mmap.growingMmapEnabled",
 		Version:      "2.4.6",

pkg/util/paramtable/component_param_test.go

@@ -454,6 +454,8 @@ func TestComponentParam(t *testing.T) {
 
 		assert.Equal(t, 4, Params.BloomFilterApplyParallelFactor.GetAsInt())
 		assert.Equal(t, "/var/lib/milvus/data/mmap", Params.MmapDirPath.GetValue())
+
+		assert.Equal(t, true, Params.MmapChunkCache.GetAsBool())
 	})
 
 	t.Run("test dataCoordConfig", func(t *testing.T) {