YT-17316: Prefetching chunk fragment reader

8cfdde973b41ffcb84c44f00faa7254fabeb3855

yt/yt/client/chunk_client/config.cpp

@@ -423,6 +423,9 @@ void TChunkFragmentReaderConfig::Register(TRegistrar registrar)
         .Default(16_MB);
     registrar.Parameter("max_inflight_fragment_count", &TThis::MaxInflightFragmentCount)
         .Default(8192);
+
+    registrar.Parameter("prefetch_whole_blocks", &TThis::PrefetchWholeBlocks)
+        .Default(false);
 }
 
 ////////////////////////////////////////////////////////////////////////////////

yt/yt/client/chunk_client/config.h

@@ -487,6 +487,9 @@ public:
     //! Upper bound on count of simultaneously requested fragments within a reading session.
     i64 MaxInflightFragmentCount;
 
+    // If |true| will request full blocks and store them in a cache for further access.
+    bool PrefetchWholeBlocks;
+
     REGISTER_YSON_STRUCT(TChunkFragmentReaderConfig);
 
     static void Register(TRegistrar registrar);