wallet2: speedup large tx construction: batch ringdb lookups

3.3 seconds -> 2.8 seconds on a test case

src/wallet/ringdb.cpp

@@ -344,12 +344,15 @@ bool ringdb::remove_rings(const crypto::chacha_key &chacha_key, const cryptonote
   return remove_rings(chacha_key, key_images);
 }
 
-bool ringdb::get_ring(const crypto::chacha_key &chacha_key, const crypto::key_image &key_image, std::vector<uint64_t> &outs)
+bool ringdb::get_rings(const crypto::chacha_key &chacha_key, const std::vector<crypto::key_image> &key_images, std::vector<std::vector<uint64_t>> &all_outs)
 {
   MDB_txn *txn;
   int dbr;
   bool tx_active = false;
 
+  all_outs.clear();
+  all_outs.reserve(key_images.size());
+
   dbr = resize_env(env, filename.c_str(), 0);
   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);
@@ -357,6 +360,10 @@ bool ringdb::get_ring(const crypto::chacha_key &chacha_key, const crypto::key_im
   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;
 
+  for (size_t i = 0; i < key_images.size(); ++i)
+  {
+  const crypto::key_image &key_image = key_images[i];
+
   MDB_val key, data;
   std::string key_ciphertext = encrypt(key_image, chacha_key, 0);
   key.mv_data = (void*)key_ciphertext.data();
@@ -367,6 +374,7 @@ bool ringdb::get_ring(const crypto::chacha_key &chacha_key, const crypto::key_im
     return false;
   THROW_WALLET_EXCEPTION_IF(data.mv_size <= 0, tools::error::wallet_internal_error, "Invalid ring data size");
 
+  std::vector<uint64_t> outs;
   bool try_v0 = false;
   std::string data_plaintext = decrypt(std::string((const char*)data.mv_data, data.mv_size), key_image, chacha_key, 1);
   try { outs = decompress_ring(data_plaintext, V1TAG); if (outs.empty()) try_v0 = true; }
@@ -380,6 +388,9 @@ bool ringdb::get_ring(const crypto::chacha_key &chacha_key, const crypto::key_im
   MDEBUG("Relative: " << boost::join(outs | boost::adaptors::transformed([](uint64_t out){return std::to_string(out);}), " "));
   outs = cryptonote::relative_output_offsets_to_absolute(outs);
   MDEBUG("Absolute: " << boost::join(outs | boost::adaptors::transformed([](uint64_t out){return std::to_string(out);}), " "));
+  all_outs.push_back(std::move(outs));
+
+  }
 
   dbr = mdb_txn_commit(txn);
   THROW_WALLET_EXCEPTION_IF(dbr, tools::error::wallet_internal_error, "Failed to commit txn getting ring from database: " + std::string(mdb_strerror(dbr)));
@@ -387,6 +398,15 @@ bool ringdb::get_ring(const crypto::chacha_key &chacha_key, const crypto::key_im
   return true;
 }
 
+bool ringdb::get_ring(const crypto::chacha_key &chacha_key, const crypto::key_image &key_image, std::vector<uint64_t> &outs)
+{
+  std::vector<std::vector<uint64_t>> all_outs;
+  if (!get_rings(chacha_key, std::vector<crypto::key_image>(1, key_image), all_outs))
+    return false;
+  outs = std::move(all_outs.front());
+  return true;
+}
+
 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;

src/wallet/ringdb.h

@@ -49,6 +49,7 @@ namespace tools
     bool remove_rings(const crypto::chacha_key &chacha_key, const std::vector<crypto::key_image> &key_images);
     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 get_rings(const crypto::chacha_key &chacha_key, const std::vector<crypto::key_image> &key_images, std::vector<std::vector<uint64_t>> &all_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);
 

src/wallet/wallet2.cpp

@@ -7606,6 +7606,14 @@ bool wallet2::get_ring(const crypto::chacha_key &key, const crypto::key_image &k
   catch (const std::exception &e) { return false; }
 }
 
+bool wallet2::get_rings(const crypto::chacha_key &key, const std::vector<crypto::key_image> &key_images, std::vector<std::vector<uint64_t>> &outs)
+{
+  if (!m_ringdb)
+    return false;
+  try { return m_ringdb->get_rings(key, key_images, outs); }
+  catch (const std::exception &e) { return false; }
+}
+
 bool wallet2::get_rings(const crypto::hash &txid, std::vector<std::pair<crypto::key_image, std::vector<uint64_t>>> &outs)
 {
   for (auto i: m_confirmed_txs)
@@ -8126,6 +8134,25 @@ void wallet2::get_outs(std::vector<std::vector<tools::wallet2::get_outs_entry>>
       }
     }
 
+    std::vector<crypto::key_image> ring_key_images;
+    ring_key_images.reserve(selected_transfers.size());
+    std::unordered_map<crypto::key_image, std::vector<uint64_t>> existing_rings;
+    for(size_t idx: selected_transfers)
+    {
+      const transfer_details &td = m_transfers[idx];
+      if (td.m_key_image_known && !td.m_key_image_partial)
+        ring_key_images.push_back(td.m_key_image);
+    }
+    if (!ring_key_images.empty())
+    {
+      std::vector<std::vector<uint64_t>> all_outs;
+      if (get_rings(get_ringdb_key(), ring_key_images, all_outs))
+      {
+        for (size_t i = 0; i < ring_key_images.size(); ++i)
+          existing_rings[ring_key_images[i]] = std::move(all_outs[i]);
+      }
+    }
+
     // we ask for more, to have spares if some outputs are still locked
     size_t base_requested_outputs_count = (size_t)((fake_outputs_count + 1) * 1.5 + 1);
     LOG_PRINT_L2("base_requested_outputs_count: " << base_requested_outputs_count);
@@ -8248,9 +8275,12 @@ void wallet2::get_outs(std::vector<std::vector<tools::wallet2::get_outs_entry>>
       // if we have a known ring, use it
       if (td.m_key_image_known && !td.m_key_image_partial)
       {
-        std::vector<uint64_t> ring;
+
-        if (get_ring(get_ringdb_key(), td.m_key_image, ring))
+        const auto it = existing_rings.find(td.m_key_image);
+        const bool has_ring = it != existing_rings.end();
+        if (has_ring)
         {
+          const std::vector<uint64_t> &ring = it->second;
           MINFO("This output has a known ring, reusing (size " << ring.size() << ")");
           THROW_WALLET_EXCEPTION_IF(ring.size() > fake_outputs_count + 1, error::wallet_internal_error,
               "An output in this transaction was previously spent on another chain with ring size " +
@@ -8520,9 +8550,10 @@ void wallet2::get_outs(std::vector<std::vector<tools::wallet2::get_outs_entry>>
       // then pick outs from an existing ring, if any
       if (td.m_key_image_known && !td.m_key_image_partial)
       {
-        std::vector<uint64_t> ring;
+        const auto it = existing_rings.find(td.m_key_image);
-        if (get_ring(get_ringdb_key(), td.m_key_image, ring))
+        if (it != existing_rings.end())
         {
+          const std::vector<uint64_t> &ring = it->second;
           for (uint64_t out: ring)
           {
             if (out < num_outs)

src/wallet/wallet2.h

@@ -1558,6 +1558,7 @@ private:
     const std::string get_ring_database() const { return m_ring_database; }
     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 get_rings(const crypto::chacha_key &key, const std::vector<crypto::key_image> &key_images, std::vector<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);