From dc6c0696fd0b9cd28c8195fc6d90390f5aeaf08f Mon Sep 17 00:00:00 2001
From: moneromooo-monero <moneromooo-monero@users.noreply.github.com>
Date: Thu, 16 Aug 2018 18:16:36 +0000
Subject: [PATCH] db_lmdb: speedup the get_output_distribution common case

---
 src/blockchain_db/lmdb/db_lmdb.cpp | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 627038ca7..1e817bb07 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -1971,14 +1971,25 @@ std::vector<uint64_t> BlockchainLMDB::get_block_cumulative_rct_outputs(const std
 
   MDB_val v;
 
+  uint64_t prev_height = heights[0];
   for (uint64_t height: heights)
   {
-    MDB_val_set(v, height);
-    result = mdb_cursor_get(m_cur_block_info, (MDB_val *)&zerokval, &v, MDB_GET_BOTH);
+    if (height == prev_height + 1)
+    {
+      MDB_val k2;
+      result = mdb_cursor_get(m_cur_block_info, &k2, &v, MDB_NEXT);
+    }
+    else
+    {
+      v.mv_size = sizeof(uint64_t);
+      v.mv_data = (void*)&height;
+      result = mdb_cursor_get(m_cur_block_info, (MDB_val *)&zerokval, &v, MDB_GET_BOTH);
+    }
     if (result)
       throw0(DB_ERROR(lmdb_error("Error attempting to retrieve rct distribution from the db: ", result).c_str()));
     const mdb_block_info *bi = (const mdb_block_info *)v.mv_data;
     res.push_back(bi->bi_cum_rct);
+    prev_height = height;
   }
 
   TXN_POSTFIX_RDONLY();