ArticMine's new block weight algorithm

This curbs runaway growth while still allowing substantial
spikes in block weight

Original specification from ArticMine:

here is the scaling proposal
Define: LongTermBlockWeight
Before fork:
LongTermBlockWeight = BlockWeight
At or after fork:
LongTermBlockWeight = min(BlockWeight, 1.4*LongTermEffectiveMedianBlockWeight)
Note: To avoid possible consensus issues over rounding the LongTermBlockWeight for a given block should be calculated to the nearest byte, and stored as a integer in the block itself. The stored LongTermBlockWeight is then used for future calculations of the LongTermEffectiveMedianBlockWeight and not recalculated each time.
Define:   LongTermEffectiveMedianBlockWeight
LongTermEffectiveMedianBlockWeight = max(300000, MedianOverPrevious100000Blocks(LongTermBlockWeight))
Change Definition of EffectiveMedianBlockWeight
From (current definition)
EffectiveMedianBlockWeight  = max(300000, MedianOverPrevious100Blocks(BlockWeight))
To (proposed definition)
EffectiveMedianBlockWeight  = min(max(300000, MedianOverPrevious100Blocks(BlockWeight)), 50*LongTermEffectiveMedianBlockWeight)
Notes:
1) There are no other changes to the existing penalty formula, median calculation, fees etc.
2) There is the requirement to store the LongTermBlockWeight of a block unencrypted in the block itself. This  is to avoid possible consensus issues over rounding and also to prevent the calculations from becoming unwieldy as we move away from the fork.
3) When the  EffectiveMedianBlockWeight cap is reached it is still possible to mine blocks up to 2x the EffectiveMedianBlockWeight by paying the corresponding penalty.

Note: the long term block weight is stored in the database, but not in the actual block itself,
since it requires recalculating anyway for verification.

2 files changed, 3 insertions, 0 deletions

diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index b524273bf..eae8cc531 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -1322,6 +1322,7 @@ namespace cryptonote
     response.block_size = response.block_weight = m_core.get_blockchain_storage().get_db().get_block_weight(height);
     response.num_txes = blk.tx_hashes.size();
     response.pow_hash = fill_pow_hash ? string_tools::pod_to_hex(get_block_longhash(blk, height)) : "";
+    response.long_term_weight = m_core.get_blockchain_storage().get_db().get_block_long_term_weight(height);
     return true;
   }
   //------------------------------------------------------------------------------------------------------------------------------
diff --git a/src/rpc/core_rpc_server_commands_defs.h b/src/rpc/core_rpc_server_commands_defs.h
index dfad5d6a7..e52e4fc67 100644
--- a/src/rpc/core_rpc_server_commands_defs.h
+++ b/src/rpc/core_rpc_server_commands_defs.h
@@ -1172,6 +1172,7 @@ namespace cryptonote
       uint64_t block_weight;
       uint64_t num_txes;
       std::string pow_hash;
+      uint64_t long_term_weight;
       
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(major_version)
@@ -1190,6 +1191,7 @@ namespace cryptonote
         KV_SERIALIZE_OPT(block_weight, (uint64_t)0)
         KV_SERIALIZE(num_txes)
         KV_SERIALIZE(pow_hash)
+        KV_SERIALIZE_OPT(long_term_weight, (uint64_t)0)
       END_KV_SERIALIZE_MAP()
   };