blockchain_db: speedup tx output gathering

We know all the data we'll want for getblocks.bin is contiguous

src/blockchain_db/blockchain_db.h

@@ -1329,10 +1329,11 @@ public:
    * If an output cannot be found, the subclass should throw OUTPUT_DNE.
    *
    * @param tx_id a transaction ID
+   * @param n_txes how many txes to get data for, starting with tx_id
    *
    * @return a list of amount-specific output indices
    */
-  virtual std::vector<uint64_t> get_tx_amount_output_indices(const uint64_t tx_id) const = 0;
+  virtual std::vector<std::vector<uint64_t>> get_tx_amount_output_indices(const uint64_t tx_id, size_t n_txes = 1) const = 0;
 
   /**
    * @brief check if a key image is stored as spent

src/blockchain_db/lmdb/db_lmdb.cpp

@@ -1019,7 +1019,8 @@ void BlockchainLMDB::remove_tx_outputs(const uint64_t tx_id, const transaction&
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
 
-  std::vector<uint64_t> amount_output_indices = get_tx_amount_output_indices(tx_id);
+  std::vector<std::vector<uint64_t>> amount_output_indices_set = get_tx_amount_output_indices(tx_id, 1);
+  const std::vector<uint64_t> &amount_output_indices = amount_output_indices_set.front();
 
   if (amount_output_indices.empty())
   {
@@ -2628,7 +2629,7 @@ tx_out_index BlockchainLMDB::get_output_tx_and_index(const uint64_t& amount, con
   return indices[0];
 }
 
-std::vector<uint64_t> BlockchainLMDB::get_tx_amount_output_indices(const uint64_t tx_id) const
+std::vector<std::vector<uint64_t>> BlockchainLMDB::get_tx_amount_output_indices(uint64_t tx_id, size_t n_txes) const
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
 
@@ -2637,35 +2638,40 @@ std::vector<uint64_t> BlockchainLMDB::get_tx_amount_output_indices(const uint64_
   TXN_PREFIX_RDONLY();
   RCURSOR(tx_outputs);
 
-  int result = 0;
   MDB_val_set(k_tx_id, tx_id);
   MDB_val v;
-  std::vector<uint64_t> amount_output_indices;
+  std::vector<std::vector<uint64_t>> amount_output_indices_set;
+  amount_output_indices_set.reserve(n_txes);
 
-  result = mdb_cursor_get(m_cur_tx_outputs, &k_tx_id, &v, MDB_SET);
-  if (result == MDB_NOTFOUND)
-    LOG_PRINT_L0("WARNING: Unexpected: tx has no amount indices stored in "
-        "tx_outputs, but it should have an empty entry even if it's a tx without "
-        "outputs");
-  else if (result)
-    throw0(DB_ERROR(lmdb_error("DB error attempting to get data for tx_outputs[tx_index]", result).c_str()));
-
-  const uint64_t* indices = (const uint64_t*)v.mv_data;
-  int num_outputs = v.mv_size / sizeof(uint64_t);
-
-  amount_output_indices.reserve(num_outputs);
-  for (int i = 0; i < num_outputs; ++i)
+  MDB_cursor_op op = MDB_SET;
+  while (n_txes-- > 0)
   {
-    // LOG_PRINT_L0("amount output index[" << 2*i << "]" << ": " << paired_indices[2*i] << "  global output index: " << paired_indices[2*i+1]);
-    amount_output_indices.push_back(indices[i]);
+    int result = mdb_cursor_get(m_cur_tx_outputs, &k_tx_id, &v, op);
+    if (result == MDB_NOTFOUND)
+      LOG_PRINT_L0("WARNING: Unexpected: tx has no amount indices stored in "
+          "tx_outputs, but it should have an empty entry even if it's a tx without "
+          "outputs");
+    else if (result)
+      throw0(DB_ERROR(lmdb_error("DB error attempting to get data for tx_outputs[tx_index]", result).c_str()));
+
+    op = MDB_NEXT;
+
+    const uint64_t* indices = (const uint64_t*)v.mv_data;
+    size_t num_outputs = v.mv_size / sizeof(uint64_t);
+
+    amount_output_indices_set.resize(amount_output_indices_set.size() + 1);
+    std::vector<uint64_t> &amount_output_indices = amount_output_indices_set.back();
+    amount_output_indices.reserve(num_outputs);
+    for (size_t i = 0; i < num_outputs; ++i)
+    {
+      amount_output_indices.push_back(indices[i]);
+    }
   }
-  indices = nullptr;
 
   TXN_POSTFIX_RDONLY();
-  return amount_output_indices;
+  return amount_output_indices_set;
 }
 
-
 bool BlockchainLMDB::has_key_image(const crypto::key_image& img) const
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);

src/blockchain_db/lmdb/db_lmdb.h

@@ -252,7 +252,7 @@ public:
   virtual tx_out_index get_output_tx_and_index(const uint64_t& amount, const uint64_t& index) const;
   virtual void get_output_tx_and_index(const uint64_t& amount, const std::vector<uint64_t> &offsets, std::vector<tx_out_index> &indices) const;
 
-  virtual std::vector<uint64_t> get_tx_amount_output_indices(const uint64_t tx_id) const;
+  virtual std::vector<std::vector<uint64_t>> get_tx_amount_output_indices(const uint64_t tx_id, size_t n_txes) const;
 
   virtual bool has_key_image(const crypto::key_image& img) const;
 

src/cryptonote_core/blockchain.cpp

@@ -2297,6 +2297,22 @@ bool Blockchain::check_for_double_spend(const transaction& tx, key_images_contai
   return true;
 }
 //------------------------------------------------------------------
+bool Blockchain::get_tx_outputs_gindexs(const crypto::hash& tx_id, size_t n_txes, std::vector<std::vector<uint64_t>>& indexs) const
+{
+  LOG_PRINT_L3("Blockchain::" << __func__);
+  CRITICAL_REGION_LOCAL(m_blockchain_lock);
+  uint64_t tx_index;
+  if (!m_db->tx_exists(tx_id, tx_index))
+  {
+    MERROR_VER("get_tx_outputs_gindexs failed to find transaction with id = " << tx_id);
+    return false;
+  }
+  indexs = m_db->get_tx_amount_output_indices(tx_index, n_txes);
+  CHECK_AND_ASSERT_MES(n_txes == indexs.size(), false, "Wrong indexs size");
+
+  return true;
+}
+//------------------------------------------------------------------
 bool Blockchain::get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs) const
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
@@ -2307,16 +2323,9 @@ bool Blockchain::get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<u
     MERROR_VER("get_tx_outputs_gindexs failed to find transaction with id = " << tx_id);
     return false;
   }
-
-  // get amount output indexes, currently referred to in parts as "output global indices", but they are actually specific to amounts
-  indexs = m_db->get_tx_amount_output_indices(tx_index);
-  if (indexs.empty())
-  {
-    // empty indexs is only valid if the vout is empty, which is legal but rare
-    cryptonote::transaction tx = m_db->get_tx(tx_id);
-    CHECK_AND_ASSERT_MES(tx.vout.empty(), false, "internal error: global indexes for transaction " << tx_id << " is empty, and tx vout is not");
-  }
-
+  std::vector<std::vector<uint64_t>> indices = m_db->get_tx_amount_output_indices(tx_index, 1);
+  CHECK_AND_ASSERT_MES(indices.size() == 1, false, "Wrong indices size");
+  indexs = indices.front();
   return true;
 }
 //------------------------------------------------------------------

src/cryptonote_core/blockchain.h

@@ -516,10 +516,12 @@ namespace cryptonote
      *
      * @param tx_id the hash of the transaction to fetch indices for
      * @param indexs return-by-reference the global indices for the transaction's outputs
+     * @param n_txes how many txes in a row to get results for
      *
      * @return false if the transaction does not exist, or if no indices are found, otherwise true
      */
     bool get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs) const;
+    bool get_tx_outputs_gindexs(const crypto::hash& tx_id, size_t n_txes, std::vector<std::vector<uint64_t>>& indexs) const;
 
     /**
      * @brief stores the blockchain

src/cryptonote_core/cryptonote_core.cpp

@@ -1220,6 +1220,11 @@ namespace cryptonote
     return m_blockchain_storage.get_tx_outputs_gindexs(tx_id, indexs);
   }
   //-----------------------------------------------------------------------------------------------
+  bool core::get_tx_outputs_gindexs(const crypto::hash& tx_id, size_t n_txes, std::vector<std::vector<uint64_t>>& indexs) const
+  {
+    return m_blockchain_storage.get_tx_outputs_gindexs(tx_id, n_txes, indexs);
+  }
+  //-----------------------------------------------------------------------------------------------
   void core::pause_mine()
   {
     m_miner.pause();

src/cryptonote_core/cryptonote_core.h

@@ -534,6 +534,7 @@ namespace cryptonote
       * @note see Blockchain::get_tx_outputs_gindexs
       */
      bool get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs) const;
+     bool get_tx_outputs_gindexs(const crypto::hash& tx_id, size_t n_txes, std::vector<std::vector<uint64_t>>& indexs) const;
 
      /**
       * @copydoc Blockchain::get_tail_id

src/rpc/core_rpc_server.cpp

@@ -252,19 +252,11 @@ namespace cryptonote
       pruned_size += bd.first.first.size();
       unpruned_size += bd.first.first.size();
       res.output_indices.push_back(COMMAND_RPC_GET_BLOCKS_FAST::block_output_indices());
-      res.output_indices.back().indices.push_back(COMMAND_RPC_GET_BLOCKS_FAST::tx_output_indices());
-      if (!req.no_miner_tx)
-      {
-        bool r = m_core.get_tx_outputs_gindexs(bd.first.second, res.output_indices.back().indices.back().indices);
-        if (!r)
-        {
-          res.status = "Failed";
-          return false;
-        }
-      }
       ntxes += bd.second.size();
+      res.output_indices.back().indices.reserve(1 + bd.second.size());
+      if (req.no_miner_tx)
+        res.output_indices.back().indices.push_back(COMMAND_RPC_GET_BLOCKS_FAST::tx_output_indices());
       res.blocks.back().txs.reserve(bd.second.size());
-      res.output_indices.back().indices.reserve(bd.second.size());
       for (std::vector<std::pair<crypto::hash, cryptonote::blobdata>>::iterator i = bd.second.begin(); i != bd.second.end(); ++i)
       {
         unpruned_size += i->second.size();
@@ -272,14 +264,25 @@ namespace cryptonote
         i->second.clear();
         i->second.shrink_to_fit();
         pruned_size += res.blocks.back().txs.back().size();
+      }
 
-        res.output_indices.back().indices.push_back(COMMAND_RPC_GET_BLOCKS_FAST::tx_output_indices());
-        bool r = m_core.get_tx_outputs_gindexs(i->first, res.output_indices.back().indices.back().indices);
+      const size_t n_txes_to_lookup = bd.second.size() + (req.no_miner_tx ? 0 : 1);
+      if (n_txes_to_lookup > 0)
+      {
+        std::vector<std::vector<uint64_t>> indices;
+        bool r = m_core.get_tx_outputs_gindexs(req.no_miner_tx ? bd.second.front().first : bd.first.second, n_txes_to_lookup, indices);
         if (!r)
         {
           res.status = "Failed";
           return false;
         }
+        if (indices.size() != n_txes_to_lookup || res.output_indices.back().indices.size() != (req.no_miner_tx ? 1 : 0))
+        {
+          res.status = "Failed";
+          return false;
+        }
+        for (size_t i = 0; i < indices.size(); ++i)
+          res.output_indices.back().indices.push_back({std::move(indices[i])});
       }
     }
 

tests/unit_tests/testdb.h

@@ -96,7 +96,7 @@ public:
   virtual void get_output_key(const epee::span<const uint64_t> &amounts, const std::vector<uint64_t> &offsets, std::vector<cryptonote::output_data_t> &outputs, bool allow_partial = false) {}
   virtual bool can_thread_bulk_indices() const { return false; }
   virtual std::vector<uint64_t> get_tx_output_indices(const crypto::hash& h) const { return std::vector<uint64_t>(); }
-  virtual std::vector<uint64_t> get_tx_amount_output_indices(const uint64_t tx_index) const { return std::vector<uint64_t>(); }
+  virtual std::vector<std::vector<uint64_t>> get_tx_amount_output_indices(const uint64_t tx_index, size_t n_txes) const { return std::vector<std::vector<uint64_t>>(); }
   virtual bool has_key_image(const crypto::key_image& img) const { return false; }
   virtual void remove_block() { }
   virtual uint64_t add_transaction_data(const crypto::hash& blk_hash, const cryptonote::transaction& tx, const crypto::hash& tx_hash, const crypto::hash& tx_prunable_hash) {return 0;}