update followers in 24-3

ydb/core/mind/hive/data_center_info.h

@@ -0,0 +1,21 @@
+#include "hive.h"
+#include "hive_events.h"
+
+namespace NKikimr {
+namespace NHive {
+
+struct TDataCenterInfo {
+    using TFullFollowerGroupId = std::pair<TTabletId, TFollowerGroupId>;
+    using TFollowerIter = TList<TFollowerTabletInfo>::iterator; // list iterators are not invalidated
+
+    std::unordered_set<TNodeId> RegisteredNodes;
+    bool UpdateScheduled = false;
+    std::unordered_map<TFullFollowerGroupId, std::vector<TFollowerIter>> Followers;
+
+    bool IsRegistered() const {
+        return !RegisteredNodes.empty();
+    }
+};
+
+} // NHive
+} // NKikimr

ydb/core/mind/hive/follower_group.h

@@ -67,6 +67,17 @@ struct TFollowerGroup {
         }
     }
 
+    ui32 GetFollowerCountForDataCenter(const TDataCenterId& dc) const {
+        if (!FollowerCountPerDataCenter) {
+            return 0;
+        }
+        if (NodeFilter.IsAllowedDataCenter(dc)) {
+            return FollowerCount;
+        } else {
+            return 0;
+        }
+    }
+
     void SetFollowerCount(ui32 followerCount) {
         FollowerCount = followerCount;
     }

ydb/core/mind/hive/hive.cpp

@@ -82,11 +82,11 @@ NMetrics::EResource GetDominantResourceType(const TResourceNormalizedValues& nor
 }
 
 TNodeFilter::TNodeFilter(const THive& hive)
-    : Hive(hive)
+    : Hive(&hive)
 {}
 
 TArrayRef<const TSubDomainKey> TNodeFilter::GetEffectiveAllowedDomains() const {
-    const auto* objectDomainInfo = Hive.FindDomain(ObjectDomain);
+    const auto* objectDomainInfo = Hive->FindDomain(ObjectDomain);
 
     if (!objectDomainInfo) {
         return {AllowedDomains.begin(), AllowedDomains.end()};
@@ -100,6 +100,13 @@ TArrayRef<const TSubDomainKey> TNodeFilter::GetEffectiveAllowedDomains() const {
     }
 }
 
+bool TNodeFilter::IsAllowedDataCenter(TDataCenterId dc) const {
+    if (AllowedDataCenters.empty()) {
+        return true;
+    }
+    return std::find(AllowedDataCenters.begin(), AllowedDataCenters.end(), dc) != AllowedDataCenters.end();
+}
+
 template <typename K, typename V>
 std::unordered_map<V, K> MakeReverseMap(const std::unordered_map<K, V>& map) {
     std::unordered_map<V, K> result;

ydb/core/mind/hive/hive.h

@@ -323,13 +323,55 @@ struct TNodeFilter {
     TSubDomainKey ObjectDomain;
     TTabletTypes::EType TabletType = TTabletTypes::TypeInvalid;
 
-    const THive& Hive;
+    const THive* Hive;
 
     explicit TNodeFilter(const THive& hive);
 
     TArrayRef<const TSubDomainKey> GetEffectiveAllowedDomains() const;
+
+    bool IsAllowedDataCenter(TDataCenterId dc) const;
+};
+
+struct TFollowerUpdates {
+    enum class EAction {
+        Create,
+        Update,
+        Delete,
+    };
+
+    struct TUpdate {
+        EAction Action;
+        TFullTabletId TabletId;
+        TFollowerGroupId GroupId;
+        TDataCenterId DataCenter;
+    };
+
+    std::deque<TUpdate> Updates;
+
+    bool Empty() const {
+        return Updates.empty();
+    }
+
+    void Create(TFullTabletId leaderTablet, TFollowerGroupId group, TDataCenterId dc) {
+        Updates.emplace_back(EAction::Create, leaderTablet, group, dc);
+    }
+
+    void Update(TFullTabletId tablet, TDataCenterId dc) {
+        Updates.emplace_back(EAction::Update, tablet, 0, dc);
+    }
+
+    void Delete(TFullTabletId tablet, TFollowerGroupId group, TDataCenterId dc) {
+        Updates.emplace_back(EAction::Delete, tablet, group, dc);
+    }
+
+    TUpdate Pop() {
+        TUpdate update = Updates.front();
+        Updates.pop_front();
+        return update;
+    }
 };
 
+
 } // NHive
 } // NKikimr
 

ydb/core/mind/hive/hive_events.h

@@ -34,6 +34,8 @@ struct TEvPrivate {
         EvDeleteNode,
         EvCanMoveTablets,
         EvRefreshScaleRecommendation,
+        EvUpdateDataCenterFollowers,
+        EvUpdateFollowers,
         EvEnd
     };
 
@@ -123,6 +125,15 @@ struct TEvPrivate {
     struct TEvCanMoveTablets : TEventLocal<TEvCanMoveTablets, EvCanMoveTablets> {};
 
     struct TEvRefreshScaleRecommendation : TEventLocal<TEvRefreshScaleRecommendation, EvRefreshScaleRecommendation> {};
+
+    struct TEvUpdateDataCenterFollowers : TEventLocal<TEvUpdateDataCenterFollowers, EvUpdateDataCenterFollowers> {
+        TDataCenterId DataCenter;
+
+        TEvUpdateDataCenterFollowers(TDataCenterId dataCenter) : DataCenter(dataCenter) {};
+    };
+
+    struct TEvUpdateFollowers : TEventLocal<TEvUpdateFollowers, EvUpdateFollowers> {
+    };
 };
 
 } // NHive