1 files changed, 24 insertions, 10 deletions

diff --git a/src/txmempool.h b/src/txmempool.h
index 8764bbcf13..f513f14af6 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -501,6 +501,11 @@ private:
     mutable uint64_t m_epoch;
     mutable bool m_has_epoch_guard;
 
+    // In-memory counter for external mempool tracking purposes.
+    // This number is incremented once every time a transaction
+    // is added or removed from the mempool for any reason.
+    mutable uint64_t m_sequence_number{1};
+
     void trackPackageRemoved(const CFeeRate& rate) EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     bool m_is_loaded GUARDED_BY(cs){false};
@@ -587,10 +592,9 @@ private:
     std::vector<indexed_transaction_set::const_iterator> GetSortedDepthAndScore() const EXCLUSIVE_LOCKS_REQUIRED(cs);
 
     /**
-     * track locally submitted transactions to periodically retry initial broadcast
-     * map of txid -> wtxid
+     * Track locally submitted transactions to periodically retry initial broadcast.
      */
-    std::map<uint256, uint256> m_unbroadcast_txids GUARDED_BY(cs);
+    std::set<uint256> m_unbroadcast_txids GUARDED_BY(cs);
 
 public:
     indirectmap<COutPoint, const CTransaction*> mapNextTx GUARDED_BY(cs);
@@ -752,19 +756,20 @@ public:
     size_t DynamicMemoryUsage() const;
 
     /** Adds a transaction to the unbroadcast set */
-    void AddUnbroadcastTx(const uint256& txid, const uint256& wtxid) {
+    void AddUnbroadcastTx(const uint256& txid)
+    {
         LOCK(cs);
-        // Sanity Check: the transaction should also be in the mempool
-        if (exists(txid)) {
-            m_unbroadcast_txids[txid] = wtxid;
-        }
-    }
+        // Sanity check the transaction is in the mempool & insert into
+        // unbroadcast set.
+        if (exists(txid)) m_unbroadcast_txids.insert(txid);
+    };
 
     /** Removes a transaction from the unbroadcast set */
     void RemoveUnbroadcastTx(const uint256& txid, const bool unchecked = false);
 
     /** Returns transactions in unbroadcast set */
-    std::map<uint256, uint256> GetUnbroadcastTxs() const {
+    std::set<uint256> GetUnbroadcastTxs() const
+    {
         LOCK(cs);
         return m_unbroadcast_txids;
     }
@@ -776,6 +781,15 @@ public:
         return m_unbroadcast_txids.count(txid) != 0;
     }
 
+    /** Guards this internal counter for external reporting */
+    uint64_t GetAndIncrementSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
+        return m_sequence_number++;
+    }
+
+    uint64_t GetSequence() const EXCLUSIVE_LOCKS_REQUIRED(cs) {
+        return m_sequence_number;
+    }
+
 private:
     /** UpdateForDescendants is used by UpdateTransactionsFromBlock to update
      *  the descendants for a single transaction that has been added to the