wallet2: speedup large tx construction: batch ringdb updates

5.2 seconds -> 4.1 seconds on a test case

src/wallet/ringdb.cpp

@@ -387,20 +387,24 @@ bool ringdb::get_ring(const crypto::chacha_key &chacha_key, const crypto::key_im
   return true;
 }
 
-bool ringdb::set_ring(const crypto::chacha_key &chacha_key, const crypto::key_image &key_image, const std::vector<uint64_t> &outs, bool relative)
+bool ringdb::set_rings(const crypto::chacha_key &chacha_key, const std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> &rings, bool relative)
 {
   MDB_txn *txn;
   int dbr;
   bool tx_active = false;
 
-  dbr = resize_env(env, filename.c_str(), outs.size() * 64);
+  size_t n_outs = 0;
+  for (const auto &e: rings)
+    n_outs += e.second.size();
+  dbr = resize_env(env, filename.c_str(), n_outs * 64);
   THROW_WALLET_EXCEPTION_IF(dbr, tools::error::wallet_internal_error, "Failed to set env map size: " + std::string(mdb_strerror(dbr)));
   dbr = mdb_txn_begin(env, NULL, 0, &txn);
   THROW_WALLET_EXCEPTION_IF(dbr, tools::error::wallet_internal_error, "Failed to create LMDB transaction: " + std::string(mdb_strerror(dbr)));
   epee::misc_utils::auto_scope_leave_caller txn_dtor = epee::misc_utils::create_scope_leave_handler([&](){if (tx_active) mdb_txn_abort(txn);});
   tx_active = true;
 
-  store_relative_ring(txn, dbi_rings, key_image, relative ? outs : cryptonote::absolute_output_offsets_to_relative(outs), chacha_key);
+  for (const auto &e: rings)
+    store_relative_ring(txn, dbi_rings, e.first, relative ? e.second : cryptonote::absolute_output_offsets_to_relative(e.second), chacha_key);
 
   dbr = mdb_txn_commit(txn);
   THROW_WALLET_EXCEPTION_IF(dbr, tools::error::wallet_internal_error, "Failed to commit txn setting ring to database: " + std::string(mdb_strerror(dbr)));
@@ -408,6 +412,13 @@ bool ringdb::set_ring(const crypto::chacha_key &chacha_key, const crypto::key_im
   return true;
 }
 
+bool ringdb::set_ring(const crypto::chacha_key &chacha_key, const crypto::key_image &key_image, const std::vector<uint64_t> &outs, bool relative)
+{
+  std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> rings;
+  rings.push_back(std::make_pair(key_image, outs));
+  return set_rings(chacha_key, rings, relative);
+}
+
 bool ringdb::blackball_worker(const std::vector<std::pair<uint64_t, uint64_t>> &outputs, int op)
 {
   MDB_txn *txn;

src/wallet/ringdb.h

@@ -50,6 +50,7 @@ namespace tools
     bool remove_rings(const crypto::chacha_key &chacha_key, const cryptonote::transaction_prefix &tx);
     bool get_ring(const crypto::chacha_key &chacha_key, const crypto::key_image &key_image, std::vector<uint64_t> &outs);
     bool set_ring(const crypto::chacha_key &chacha_key, const crypto::key_image &key_image, const std::vector<uint64_t> &outs, bool relative);
+    bool set_rings(const crypto::chacha_key &chacha_key, const std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> &rings, bool relative);
 
     bool blackball(const std::pair<uint64_t, uint64_t> &output);
     bool blackball(const std::vector<std::pair<uint64_t, uint64_t>> &outputs);

src/wallet/wallet2.cpp

@@ -7644,6 +7644,15 @@ bool wallet2::set_ring(const crypto::key_image &key_image, const std::vector<uin
   catch (const std::exception &e) { return false; }
 }
 
+bool wallet2::set_rings(const std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> &rings, bool relative)
+{
+  if (!m_ringdb)
+    return false;
+
+  try { return m_ringdb->set_rings(get_ringdb_key(), rings, relative); }
+  catch (const std::exception &e) { return false; }
+}
+
 bool wallet2::unset_ring(const std::vector<crypto::key_image> &key_images)
 {
   if (!m_ringdb)
@@ -8580,6 +8589,8 @@ void wallet2::get_outs(std::vector<std::vector<tools::wallet2::get_outs_entry>>
   }
 
   // save those outs in the ringdb for reuse
+  std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> rings;
+  rings.reserve(selected_transfers.size());
   for (size_t i = 0; i < selected_transfers.size(); ++i)
   {
     const size_t idx = selected_transfers[i];
@@ -8589,9 +8600,10 @@ void wallet2::get_outs(std::vector<std::vector<tools::wallet2::get_outs_entry>>
     ring.reserve(outs[i].size());
     for (const auto &e: outs[i])
       ring.push_back(std::get<0>(e));
-    if (!set_ring(td.m_key_image, ring, false))
+    rings.push_back(std::make_pair(td.m_key_image, std::move(ring)));
-      MERROR("Failed to set ring for " << td.m_key_image);
   }
+  if (!set_rings(rings, false))
+    MERROR("Failed to set rings");
 }
 
 template<typename T>

src/wallet/wallet2.h

@@ -1559,6 +1559,7 @@ private:
     bool get_ring(const crypto::key_image &key_image, std::vector<uint64_t> &outs);
     bool get_rings(const crypto::hash &txid, std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> &outs);
     bool set_ring(const crypto::key_image &key_image, const std::vector<uint64_t> &outs, bool relative);
+    bool set_rings(const std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> &rings, bool relative);
     bool unset_ring(const std::vector<crypto::key_image> &key_images);
     bool unset_ring(const crypto::hash &txid);
     bool find_and_save_rings(bool force = true);