disable warmup for root hive (#954)

Author: vporyadke

ydb/core/mind/hive/hive_ut.cpp

@@ -4163,7 +4163,9 @@ Y_UNIT_TEST_SUITE(THiveTest) {
         static const int NUM_TABLETS = NUM_NODES * TABLETS_PER_NODE;
 
         TTestBasicRuntime runtime(NUM_NODES, false);
-        Setup(runtime, true);
+        Setup(runtime, true, 1, [](TAppPrepare& app) {
+            app.HiveConfig.SetWarmUpEnabled(true);
+        });
         const int nodeBase = runtime.GetNodeId(0);
         TActorId senderA = runtime.AllocateEdgeActor();
         const ui64 hiveTablet = MakeDefaultHiveID(0);

ydb/core/mind/hive/tx__load_everything.cpp

@@ -181,7 +181,11 @@ class TTxLoadEverything : public TTransactionBase<THive> {
         }
 
         Self->BuildCurrentConfig();
-        Self->WarmUp = Self->CurrentConfig.GetWarmUpEnabled();
+        if (Self->CurrentConfig.HasWarmUpEnabled()) {
+            Self->WarmUp = Self->CurrentConfig.GetWarmUpEnabled();
+        } else {
+            Self->WarmUp = Self->CurrentConfig.GetWarmUpEnabled() && !Self->AreWeRootHive();
+        }
 
         Self->DefaultResourceMetricsAggregates.MaximumCPU.SetWindowSize(TDuration::MilliSeconds(Self->GetMetricsWindowSize()));
         Self->DefaultResourceMetricsAggregates.MaximumMemory.SetWindowSize(TDuration::MilliSeconds(Self->GetMetricsWindowSize()));