Fixed get_block_template_backlog performance [release-v0.18]

src/cryptonote_core/tx_pool.cpp

@@ -917,26 +917,61 @@ namespace cryptonote
   {
     CRITICAL_REGION_LOCAL(m_transactions_lock);
     CRITICAL_REGION_LOCAL1(m_blockchain);
-    const relay_category category = include_sensitive ? relay_category::all : relay_category::broadcasted;
-    backlog.reserve(m_blockchain.get_txpool_tx_count(include_sensitive));
-    txpool_tx_meta_t tmp_meta;
-    m_blockchain.for_all_txpool_txes([this, &backlog, &tmp_meta](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata_ref *bd){
-      transaction tx;
-      if (!(meta.pruned ? parse_and_validate_tx_base_from_blob(*bd, tx) : parse_and_validate_tx_from_blob(*bd, tx)))
+
+    std::vector<tx_block_template_backlog_entry> tmp;
+    uint64_t total_weight = 0;
+
+    // First get everything from the mempool, filter it later
+    m_blockchain.for_all_txpool_txes([&tmp, &total_weight](const crypto::hash &txid, const txpool_tx_meta_t &meta, const cryptonote::blobdata_ref*){
+      tmp.emplace_back(tx_block_template_backlog_entry{txid, meta.weight, meta.fee});
+      total_weight += meta.weight;
+      return true;
+    }, false, include_sensitive ? relay_category::all : relay_category::broadcasted);
+
+    // Limit backlog to 112.5% of current median weight. This is enough to mine a full block with the optimal block reward
+    const uint64_t median_weight = m_blockchain.get_current_cumulative_block_weight_median();
+    const uint64_t max_backlog_weight = median_weight + (median_weight / 8);
+
+    // If the total weight is too high, choose the best paying transactions
+    if (total_weight > max_backlog_weight)
+      std::sort(tmp.begin(), tmp.end(), [](const auto& a, const auto& b){ return a.fee * b.weight > b.fee * a.weight; });
+
+    backlog.clear();
+    uint64_t w = 0;
+
+    std::unordered_set<crypto::key_image> k_images;
+
+    for (const tx_block_template_backlog_entry& e : tmp)
+    {
+      try
       {
-        MERROR("Failed to parse tx from txpool");
-        // continue
-        return true;
-      }
-      tx.set_hash(txid);
+        txpool_tx_meta_t meta;
+        if (!m_blockchain.get_txpool_tx_meta(e.id, meta))
+          continue;
 
-      tmp_meta = meta;
+        cryptonote::blobdata txblob;
+        if (!m_blockchain.get_txpool_tx_blob(e.id, txblob, relay_category::all))
+          continue;
 
-      if (is_transaction_ready_to_go(tmp_meta, txid, *bd, tx))
-        backlog.push_back({txid, meta.weight, meta.fee});
+        cryptonote::transaction tx;
+        if (is_transaction_ready_to_go(meta, e.id, txblob, tx))
+        {
+          if (have_key_images(k_images, tx))
+            continue;
+          append_key_images(k_images, tx);
 
-      return true;
-    }, true, category);
+          backlog.push_back(e);
+          w += e.weight;
+          if (w > max_backlog_weight)
+            break;
+        }
+      }
+      catch (const std::exception &e)
+      {
+        MERROR("Failed to check transaction readiness: " << e.what());
+        // continue, not fatal
+      }
+    }
   }
   //------------------------------------------------------------------
   void tx_memory_pool::get_transaction_stats(struct txpool_stats& stats, bool include_sensitive) const

src/cryptonote_core/tx_pool.h

@@ -266,7 +266,11 @@ namespace cryptonote
     void get_transaction_backlog(std::vector<tx_backlog_entry>& backlog, bool include_sensitive = false) const;
 
     /**
-     * @brief get (hash, weight, fee) for all transactions in the pool - the minimum required information to create a block template
+     * @brief get (hash, weight, fee) for transactions in the pool - the minimum required information to create a block template
+     *
+     * Not all transactions in the pool will be returned for performance reasons
+     * If there are too many transactions in the pool, only the highest-paying transactions
+     * will be returned - but enough for the miner to create a full block
      *
      * @param backlog return-by-reference that data
      * @param include_sensitive return stempool, anonymity-pool, and unrelayed txes