core: sync database based on bytes added, not blocks added

Blocks have a very wide range, whereas actual size is the relevant
quantity to consider when syncing

src/blockchain_db/blockchain_db.cpp

@@ -87,8 +87,8 @@ const command_line::arg_descriptor<std::string> arg_db_type = {
 };
 const command_line::arg_descriptor<std::string> arg_db_sync_mode = {
   "db-sync-mode"
-, "Specify sync option, using format [safe|fast|fastest]:[sync|async]:[nblocks_per_sync]." 
+, "Specify sync option, using format [safe|fast|fastest]:[sync|async]:[<nblocks_per_sync>[blocks]|<nbytes_per_sync>[bytes]]." 
-, "fast:async:1000"
+, "fast:async:250000000bytes"
 };
 const command_line::arg_descriptor<bool> arg_db_salvage  = {
   "db-salvage"

src/cryptonote_core/blockchain.cpp

@@ -156,7 +156,7 @@ static const struct {
 //------------------------------------------------------------------
 Blockchain::Blockchain(tx_memory_pool& tx_pool) :
   m_db(), m_tx_pool(tx_pool), m_hardfork(NULL), m_timestamps_and_difficulties_height(0), m_current_block_cumul_sz_limit(0), m_current_block_cumul_sz_median(0),
-  m_enforce_dns_checkpoints(false), m_max_prepare_blocks_threads(4), m_db_blocks_per_sync(1), m_db_sync_mode(db_async), m_db_default_sync(false), m_fast_sync(true), m_show_time_stats(false), m_sync_counter(0), m_cancel(false),
+  m_enforce_dns_checkpoints(false), m_max_prepare_blocks_threads(4), m_db_sync_on_blocks(true), m_db_sync_threshold(1), m_db_sync_mode(db_async), m_db_default_sync(false), m_fast_sync(true), m_show_time_stats(false), m_sync_counter(0), m_bytes_to_sync(0), m_cancel(false),
   m_difficulty_for_next_block_top_hash(crypto::null_hash),
   m_difficulty_for_next_block(1)
 {
@@ -3877,11 +3877,13 @@ bool Blockchain::cleanup_handle_incoming_blocks(bool force_sync)
         store_blockchain();
       m_sync_counter = 0;
     }
-    else if (m_db_blocks_per_sync && m_sync_counter >= m_db_blocks_per_sync)
+    else if (m_db_sync_threshold && ((m_db_sync_on_blocks && m_sync_counter >= m_db_sync_threshold) || (!m_db_sync_on_blocks && m_bytes_to_sync >= m_db_sync_threshold)))
     {
+      MDEBUG("Sync threshold met, syncing");
       if(m_db_sync_mode == db_async)
       {
         m_sync_counter = 0;
+        m_bytes_to_sync = 0;
         m_async_service.dispatch(boost::bind(&Blockchain::store_blockchain, this));
       }
       else if(m_db_sync_mode == db_sync)
@@ -4071,6 +4073,7 @@ bool Blockchain::prepare_handle_incoming_blocks(const std::vector<block_complete
       bytes += tx_blob.size();
     }
   }
+  m_bytes_to_sync += bytes;
   while (!(stop_batch = m_db->batch_start(blocks_entry.size(), bytes))) {
     m_blockchain_lock.unlock();
     m_tx_pool.unlock();
@@ -4419,7 +4422,7 @@ bool Blockchain::for_all_txpool_txes(std::function<bool(const crypto::hash&, con
   return m_db->for_all_txpool_txes(f, include_blob, include_unrelayed_txes);
 }
 
-void Blockchain::set_user_options(uint64_t maxthreads, uint64_t blocks_per_sync, blockchain_db_sync_mode sync_mode, bool fast_sync)
+void Blockchain::set_user_options(uint64_t maxthreads, bool sync_on_blocks, uint64_t sync_threshold, blockchain_db_sync_mode sync_mode, bool fast_sync)
 {
   if (sync_mode == db_defaultsync)
   {
@@ -4428,7 +4431,8 @@ void Blockchain::set_user_options(uint64_t maxthreads, uint64_t blocks_per_sync,
   }
   m_db_sync_mode = sync_mode;
   m_fast_sync = fast_sync;
-  m_db_blocks_per_sync = blocks_per_sync;
+  m_db_sync_on_blocks = sync_on_blocks;
+  m_db_sync_threshold = sync_threshold;
   m_max_prepare_blocks_threads = maxthreads;
 }
 

src/cryptonote_core/blockchain.h

@@ -729,11 +729,12 @@ namespace cryptonote
      * @brief sets various performance options
      *
      * @param maxthreads max number of threads when preparing blocks for addition
-     * @param blocks_per_sync number of blocks to cache before syncing to database
+     * @param sync_on_blocks whether to sync based on blocks or bytes
+     * @param sync_threshold number of blocks/bytes to cache before syncing to database
      * @param sync_mode the ::blockchain_db_sync_mode to use
      * @param fast_sync sync using built-in block hashes as trusted
      */
-    void set_user_options(uint64_t maxthreads, uint64_t blocks_per_sync,
+    void set_user_options(uint64_t maxthreads, bool sync_on_blocks, uint64_t sync_threshold,
         blockchain_db_sync_mode sync_mode, bool fast_sync);
 
     /**
@@ -1017,11 +1018,13 @@ namespace cryptonote
     bool m_fast_sync;
     bool m_show_time_stats;
     bool m_db_default_sync;
-    uint64_t m_db_blocks_per_sync;
+    bool m_db_sync_on_blocks;
+    uint64_t m_db_sync_threshold;
     uint64_t m_max_prepare_blocks_threads;
     uint64_t m_fake_pow_calc_time;
     uint64_t m_fake_scan_time;
     uint64_t m_sync_counter;
+    uint64_t m_bytes_to_sync;
     std::vector<uint64_t> m_timestamps;
     std::vector<difficulty_type> m_difficulties;
     uint64_t m_timestamps_and_difficulties_height;

src/cryptonote_core/cryptonote_core.cpp

@@ -439,9 +439,10 @@ namespace cryptonote
     MGINFO("Loading blockchain from folder " << folder.string() << " ...");
 
     const std::string filename = folder.string();
-    // default to fast:async:1
+    // default to fast:async:1 if overridden
     blockchain_db_sync_mode sync_mode = db_defaultsync;
-    uint64_t blocks_per_sync = 1;
+    bool sync_on_blocks = true;
+    uint64_t sync_threshold = 1;
 
     if (m_nettype == FAKECHAIN)
     {
@@ -491,7 +492,7 @@ namespace cryptonote
         else if(options[0] == "fastest")
         {
           db_flags = DBF_FASTEST;
-          blocks_per_sync = 1000; // default to fastest:async:1000
+          sync_threshold = 1000; // default to fastest:async:1000
           sync_mode = db_sync_mode_is_default ? db_defaultsync : db_async;
         }
         else
@@ -509,9 +510,22 @@ namespace cryptonote
       if(options.size() >= 3 && !safemode)
       {
         char *endptr;
-        uint64_t bps = strtoull(options[2].c_str(), &endptr, 0);
+        uint64_t threshold = strtoull(options[2].c_str(), &endptr, 0);
-        if (*endptr == '\0')
+        if (*endptr == '\0' || !strcmp(endptr, "blocks"))
-          blocks_per_sync = bps;
+        {
+          sync_on_blocks = true;
+          sync_threshold = threshold;
+        }
+        else if (!strcmp(endptr, "bytes"))
+        {
+          sync_on_blocks = false;
+          sync_threshold = threshold;
+        }
+        else
+        {
+          LOG_ERROR("Invalid db sync mode: " << options[2]);
+          return false;
+        }
       }
 
       if (db_salvage)
@@ -528,7 +542,7 @@ namespace cryptonote
     }
 
     m_blockchain_storage.set_user_options(blocks_threads,
-        blocks_per_sync, sync_mode, fast_sync);
+        sync_on_blocks, sync_threshold, sync_mode, fast_sync);
 
     const std::pair<uint8_t, uint64_t> regtest_hard_forks[3] = {std::make_pair(1, 0), std::make_pair(Blockchain::get_hard_fork_heights(MAINNET).back().version, 1), std::make_pair(0, 0)};
     const cryptonote::test_options regtest_test_options = {