BlockTemplate: wait for 10 seconds before including new transactions

src/block_template.cpp

@@ -194,9 +194,22 @@ void BlockTemplate::update(const MinerData& data, const Mempool& mempool, Wallet
 	m_difficulty = data.difficulty;
 	m_seedHash = data.seed_hash;
 
+	const time_t cur_time = time(nullptr);
+
+	// Only choose transactions that were received 10 or more seconds ago
+	size_t total_mempool_transactions;
 	{
+		m_mempoolTxs.clear();
+
 		ReadLock mempool_lock(mempool.m_lock);
-		m_mempoolTxs = mempool.m_transactions;
+
+		total_mempool_transactions = mempool.m_transactions.size();
+
+		for (auto& it : mempool.m_transactions) {
+			if (cur_time >= it.second.time_received + 10) {
+				m_mempoolTxs.emplace_back(it.second);
+			}
+		}
 	}
 
 	// Safeguard for busy mempool moments
@@ -211,6 +224,8 @@ void BlockTemplate::update(const MinerData& data, const Mempool& mempool, Wallet
 		m_mempoolTxs.resize(1000);
 	}
 
+	LOGINFO(4, "mempool has " << total_mempool_transactions << " transactions, taking " << m_mempoolTxs.size() << " transactions from it");
+
 	const uint64_t base_reward = get_base_reward(data.already_generated_coins);
 
 	uint64_t total_tx_fees = 0;
@@ -223,7 +238,7 @@ void BlockTemplate::update(const MinerData& data, const Mempool& mempool, Wallet
 	const uint64_t max_reward = base_reward + total_tx_fees;
 
 	LOGINFO(3, "base  reward = " << log::Gray() << log::XMRAmount(base_reward) << log::NoColor() <<
-		", mempool: " << log::Gray() << m_mempoolTxs.size() << log::NoColor() <<
+		", " << log::Gray() << m_mempoolTxs.size() << log::NoColor() <<
 		" transactions, fees = " << log::Gray() << log::XMRAmount(total_tx_fees) << log::NoColor() <<
 		", weight = " << log::Gray() << total_tx_weight);
 
@@ -237,7 +252,7 @@ void BlockTemplate::update(const MinerData& data, const Mempool& mempool, Wallet
 	m_poolBlockTemplate->m_minorVersion = HARDFORK_SUPPORTED_VERSION;
 
 	// Timestamp
-	m_timestamp = time(nullptr);
+	m_timestamp = cur_time;
 	if (m_timestamp <= data.median_timestamp) {
 		LOGWARN(2, "timestamp adjusted from " << m_timestamp << " to " << data.median_timestamp + 1 << ". Fix your system time!");
 		m_timestamp = data.median_timestamp + 1;

src/common.h

@@ -226,12 +226,13 @@ difficulty_type operator+(const difficulty_type& a, const difficulty_type& b);
 
 struct TxMempoolData
 {
-	FORCEINLINE TxMempoolData() : id(), blob_size(0), weight(0), fee(0) {}
+	FORCEINLINE TxMempoolData() : id(), blob_size(0), weight(0), fee(0), time_received(0) {}
 
 	hash id;
 	uint64_t blob_size;
 	uint64_t weight;
 	uint64_t fee;
+	time_t time_received;
 };
 
 struct MinerData

src/mempool.cpp

@@ -37,20 +37,33 @@ void Mempool::add(const TxMempoolData& tx)
 {
 	WriteLock lock(m_lock);
 
-	for (const TxMempoolData& old_tx : m_transactions) {
-		if (old_tx.id == tx.id) {
-			LOGWARN(1, "duplicate transaction with id = " << tx.id << ", skipped");
-			return;
-		}
+	if (!m_transactions.emplace(tx.id, tx).second) {
+		LOGWARN(1, "duplicate transaction with id = " << tx.id << ", skipped");
 	}
-
-	m_transactions.push_back(tx);
 }
 
 void Mempool::swap(std::vector<TxMempoolData>& transactions)
 {
+	const time_t cur_time = time(nullptr);
+
 	WriteLock lock(m_lock);
-	m_transactions.swap(transactions);
+
+	// Initialize time_received for all transactions
+	for (TxMempoolData& data : transactions) {
+		auto it = m_transactions.find(data.id);
+		if (it != m_transactions.end()) {
+			data.time_received = it->second.time_received;
+		}
+		else {
+			data.time_received = cur_time;
+		}
+	}
+
+	m_transactions.clear();
+
+	for (TxMempoolData& data : transactions) {
+		m_transactions.emplace(data.id, data);
+	}
 }
 
 } // namespace p2pool

src/mempool.h

@@ -18,6 +18,7 @@
 #pragma once
 
 #include "uv_util.h"
+#include <unordered_map>
 
 namespace p2pool {
 
@@ -34,7 +35,7 @@ public:
 
 public:
 	mutable uv_rwlock_t m_lock;
-	std::vector<TxMempoolData> m_transactions;
+	std::unordered_map<hash, TxMempoolData> m_transactions;
 };
 
 } // namespace p2pool

src/zmq_reader.cpp

@@ -152,6 +152,8 @@ void ZMQReader::parse(char* data, size_t size)
 			return;
 		}
 
+		m_tx.time_received = time(nullptr);
+
 		for (SizeType i = 0, n = doc.Size(); i < n; ++i) {
 			const auto& v = doc[i];
 			if (PARSE(v, m_tx, id) && PARSE(v, m_tx, blob_size) && PARSE(v, m_tx, weight) && PARSE(v, m_tx, fee)) {