add a way to turn off computation of object distribution

3 files changed, 33 insertions, 2 deletions

diff --git a/ydb/core/mind/hive/hive_impl.cpp b/ydb/core/mind/hive/hive_impl.cpp
index d994d8a88a6..b5497776c1e 100644
--- a/ydb/core/mind/hive/hive_impl.cpp
+++ b/ydb/core/mind/hive/hive_impl.cpp
@@ -593,6 +593,13 @@ void THive::BuildCurrentConfig() {
         }
     }
     MakeTabletTypeSet(BalancerIgnoreTabletTypes);
+    if (!CurrentConfig.GetSpreadNeighbours()) {
+        // SpreadNeighbours can be turned off anytime, but
+        // cannot be safely turned on without Hive restart
+        // as the in-memory data on neighbours would not be accurate
+        SpreadNeighbours = false;
+        ObjectDistributions.Disable();
+    }
 }
 
 void THive::Cleanup() {
@@ -915,6 +922,7 @@ void THive::OnActivateExecutor(const TActorContext&) {
     ResourceProfiles = AppData()->ResourceProfiles ? AppData()->ResourceProfiles : new TResourceProfiles;
     BuildLocalConfig();
     ClusterConfig = AppData()->HiveConfig;
+    SpreadNeighbours = ClusterConfig.GetSpreadNeighbours();
     Send(NConsole::MakeConfigsDispatcherID(SelfId().NodeId()),
         new NConsole::TEvConfigsDispatcher::TEvSetConfigSubscriptionRequest(NKikimrConsole::TConfigItem::HiveConfigItem));
     Execute(CreateInitScheme());
@@ -2577,6 +2585,9 @@ TDuration THive::GetBalancerCooldown() const {
 }
 
 void THive::UpdateObjectCount(TObjectId object, TNodeId node, i64 diff) {
+    if (!GetSpreadNeighbours()) {
+        return;
+    }
     ObjectDistributions.UpdateCount(object, node, diff);
     TabletCounters->Simple()[NHive::COUNTER_IMBALANCED_OBJECTS].Set(ObjectDistributions.GetImbalancedObjectsCount());
     TabletCounters->Simple()[NHive::COUNTER_WORST_OBJECT_VARIANCE].Set(ObjectDistributions.GetWorstObjectVariance());
diff --git a/ydb/core/mind/hive/hive_impl.h b/ydb/core/mind/hive/hive_impl.h
index 1b5edbe8647..6fd8aab2146 100644
--- a/ydb/core/mind/hive/hive_impl.h
+++ b/ydb/core/mind/hive/hive_impl.h
@@ -771,7 +771,7 @@ public:
     }
 
     bool GetSpreadNeighbours() const {
-        return CurrentConfig.GetSpreadNeighbours();
+        return SpreadNeighbours;
     }
 
     ui64 GetDefaultUnitIOPS() const {
diff --git a/ydb/core/mind/hive/object_distribution.h b/ydb/core/mind/hive/object_distribution.h
index 06396044b05..e441741bc10 100644
--- a/ydb/core/mind/hive/object_distribution.h
+++ b/ydb/core/mind/hive/object_distribution.h
@@ -87,6 +87,7 @@ struct TObjectDistributions {
     std::unordered_map<TObjectId, std::multiset<TObjectDistribution>::iterator> Distributions;
     ui64 ImbalancedObjects = 0;
     std::unordered_set<TNodeId> Nodes;
+    bool Enabled = true;
 
     double GetMaxImbalance() {
         if (SortedDistributions.empty()) {
@@ -103,7 +104,10 @@ struct TObjectDistributions {
     };
 
     TObjectToBalance GetObjectToBalance() {
-        Y_ABORT_UNLESS(!SortedDistributions.empty());
+        Y_DEBUG_ABORT_UNLESS(!SortedDistributions.empty());
+        if (SortedDistributions.empty()) {
+            return TObjectToBalance(0);
+        }
         const auto& dist = *SortedDistributions.rbegin();
         i64 maxCnt = *dist.SortedDistribution.rbegin();
         TObjectToBalance result(dist.Id);
@@ -159,6 +163,9 @@ struct TObjectDistributions {
 
 
     void UpdateCount(TObjectId object, TNodeId node, i64 diff) {
+        if (!Enabled) {
+            return;
+        }
         auto updateFunc = [=](TObjectDistribution& dist) {
             dist.UpdateCount(node, diff);
         };
@@ -176,6 +183,9 @@ struct TObjectDistributions {
     }
 
     void AddNode(TNodeId node) {
+        if (!Enabled) {
+            return;
+        }
         Nodes.insert(node);
         for (const auto& [obj, it] : Distributions) {
             UpdateCount(obj, node, 0);
@@ -183,6 +193,9 @@ struct TObjectDistributions {
     }
 
     void RemoveNode(TNodeId node) {
+        if (!Enabled) {
+            return;
+        }
         Nodes.erase(node);
         auto updateFunc = [=](TObjectDistribution& dist) {
             dist.RemoveNode(node);
@@ -191,6 +204,13 @@ struct TObjectDistributions {
             UpdateDistribution((it++)->first, updateFunc);
         }
     }
+
+    void Disable() {
+        Enabled = false;
+        Nodes.clear();
+        SortedDistributions.clear();
+        Distributions.clear();
+    }
 };
 
 } // NHive