RPC: Introduce getblockstats

2 files changed, 283 insertions, 0 deletions

diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 58cc8b89b2..0f8fa0619f 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -13,6 +13,7 @@
 #include <consensus/validation.h>
 #include <validation.h>
 #include <core_io.h>
+#include <index/txindex.h>
 #include <policy/feerate.h>
 #include <policy/policy.h>
 #include <primitives/transaction.h>
@@ -31,6 +32,7 @@
 
 #include <univalue.h>
 
+#include <boost/algorithm/string.hpp>
 #include <boost/thread/thread.hpp> // boost::thread::interrupt
 
 #include <memory>
@@ -1623,6 +1625,284 @@ static UniValue getchaintxstats(const JSONRPCRequest& request)
     return ret;
 }
 
+template<typename T>
+static T CalculateTruncatedMedian(std::vector<T>& scores)
+{
+    size_t size = scores.size();
+    if (size == 0) {
+        return 0;
+    }
+
+    std::sort(scores.begin(), scores.end());
+    if (size % 2 == 0) {
+        return (scores[size / 2 - 1] + scores[size / 2]) / 2;
+    } else {
+        return scores[size / 2];
+    }
+}
+
+template<typename T>
+static inline bool SetHasKeys(const std::set<T>& set) {return false;}
+template<typename T, typename Tk, typename... Args>
+static inline bool SetHasKeys(const std::set<T>& set, const Tk& key, const Args&... args)
+{
+    return (set.count(key) != 0) || SetHasKeys(set, args...);
+}
+
+// outpoint (needed for the utxo index) + nHeight + fCoinBase
+static constexpr size_t PER_UTXO_OVERHEAD = sizeof(COutPoint) + sizeof(uint32_t) + sizeof(bool);
+
+static UniValue getblockstats(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() < 1 || request.params.size() > 4) {
+        throw std::runtime_error(
+            "getblockstats hash_or_height ( stats )\n"
+            "\nCompute per block statistics for a given window. All amounts are in satoshis.\n"
+            "It won't work for some heights with pruning.\n"
+            "It won't work without -txindex for utxo_size_inc, *fee or *feerate stats.\n"
+            "\nArguments:\n"
+            "1. \"hash_or_height\"     (string or numeric, required) The block hash or height of the target block\n"
+            "2. \"stats\"              (array,  optional) Values to plot, by default all values (see result below)\n"
+            "    [\n"
+            "      \"height\",         (string, optional) Selected statistic\n"
+            "      \"time\",           (string, optional) Selected statistic\n"
+            "      ,...\n"
+            "    ]\n"
+            "\nResult:\n"
+            "{                           (json object)\n"
+            "  \"avgfee\": xxxxx,          (numeric) Average fee in the block\n"
+            "  \"avgfeerate\": xxxxx,      (numeric) Average feerate (in satoshis per virtual byte)\n"
+            "  \"avgtxsize\": xxxxx,       (numeric) Average transaction size\n"
+            "  \"blockhash\": xxxxx,       (string) The block hash (to check for potential reorgs)\n"
+            "  \"height\": xxxxx,          (numeric) The height of the block\n"
+            "  \"ins\": xxxxx,             (numeric) The number of inputs (excluding coinbase)\n"
+            "  \"maxfee\": xxxxx,          (numeric) Maximum fee in the block\n"
+            "  \"maxfeerate\": xxxxx,      (numeric) Maximum feerate (in satoshis per virtual byte)\n"
+            "  \"maxtxsize\": xxxxx,       (numeric) Maximum transaction size\n"
+            "  \"medianfee\": xxxxx,       (numeric) Truncated median fee in the block\n"
+            "  \"medianfeerate\": xxxxx,   (numeric) Truncated median feerate (in satoshis per virtual byte)\n"
+            "  \"mediantime\": xxxxx,      (numeric) The block median time past\n"
+            "  \"mediantxsize\": xxxxx,    (numeric) Truncated median transaction size\n"
+            "  \"minfee\": xxxxx,          (numeric) Minimum fee in the block\n"
+            "  \"minfeerate\": xxxxx,      (numeric) Minimum feerate (in satoshis per virtual byte)\n"
+            "  \"mintxsize\": xxxxx,       (numeric) Minimum transaction size\n"
+            "  \"outs\": xxxxx,            (numeric) The number of outputs\n"
+            "  \"subsidy\": xxxxx,         (numeric) The block subsidy\n"
+            "  \"swtotal_size\": xxxxx,    (numeric) Total size of all segwit transactions\n"
+            "  \"swtotal_weight\": xxxxx,  (numeric) Total weight of all segwit transactions divided by segwit scale factor (4)\n"
+            "  \"swtxs\": xxxxx,           (numeric) The number of segwit transactions\n"
+            "  \"time\": xxxxx,            (numeric) The block time\n"
+            "  \"total_out\": xxxxx,       (numeric) Total amount in all outputs (excluding coinbase and thus reward [ie subsidy + totalfee])\n"
+            "  \"total_size\": xxxxx,      (numeric) Total size of all non-coinbase transactions\n"
+            "  \"total_weight\": xxxxx,    (numeric) Total weight of all non-coinbase transactions divided by segwit scale factor (4)\n"
+            "  \"totalfee\": xxxxx,        (numeric) The fee total\n"
+            "  \"txs\": xxxxx,             (numeric) The number of transactions (excluding coinbase)\n"
+            "  \"utxo_increase\": xxxxx,   (numeric) The increase/decrease in the number of unspent outputs\n"
+            "  \"utxo_size_inc\": xxxxx,   (numeric) The increase/decrease in size for the utxo index (not discounting op_return and similar)\n"
+            "}\n"
+            "\nExamples:\n"
+            + HelpExampleCli("getblockstats", "1000 '[\"minfeerate\",\"avgfeerate\"]'")
+            + HelpExampleRpc("getblockstats", "1000 '[\"minfeerate\",\"avgfeerate\"]'")
+        );
+    }
+
+    LOCK(cs_main);
+
+    CBlockIndex* pindex;
+    if (request.params[0].isNum()) {
+        const int height = request.params[0].get_int();
+        const int current_tip = chainActive.Height();
+        if (height < 0) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Target block height %d is negative", height));
+        }
+        if (height > current_tip) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Target block height %d after current tip %d", height, current_tip));
+        }
+
+        pindex = chainActive[height];
+    } else {
+        const std::string strHash = request.params[0].get_str();
+        const uint256 hash(uint256S(strHash));
+        pindex = LookupBlockIndex(hash);
+        if (!pindex) {
+            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
+        }
+        if (!chainActive.Contains(pindex)) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Block is not in chain %s", Params().NetworkIDString()));
+        }
+    }
+
+    assert(pindex != nullptr);
+
+    std::set<std::string> stats;
+    if (!request.params[1].isNull()) {
+        const UniValue stats_univalue = request.params[1].get_array();
+        for (unsigned int i = 0; i < stats_univalue.size(); i++) {
+            const std::string stat = stats_univalue[i].get_str();
+            stats.insert(stat);
+        }
+    }
+
+    const CBlock block = GetBlockChecked(pindex);
+
+    const bool do_all = stats.size() == 0; // Calculate everything if nothing selected (default)
+    const bool do_mediantxsize = do_all || stats.count("mediantxsize") != 0;
+    const bool do_medianfee = do_all || stats.count("medianfee") != 0;
+    const bool do_medianfeerate = do_all || stats.count("medianfeerate") != 0;
+    const bool loop_inputs = do_all || do_medianfee || do_medianfeerate ||
+        SetHasKeys(stats, "utxo_size_inc", "totalfee", "avgfee", "avgfeerate", "minfee", "maxfee", "minfeerate", "maxfeerate");
+    const bool loop_outputs = do_all || loop_inputs || stats.count("total_out");
+    const bool do_calculate_size = do_mediantxsize ||
+        SetHasKeys(stats, "total_size", "avgtxsize", "mintxsize", "maxtxsize", "swtotal_size");
+    const bool do_calculate_weight = do_all || SetHasKeys(stats, "total_weight", "avgfeerate", "swtotal_weight", "avgfeerate", "medianfeerate", "minfeerate", "maxfeerate");
+    const bool do_calculate_sw = do_all || SetHasKeys(stats, "swtxs", "swtotal_size", "swtotal_weight");
+
+    CAmount maxfee = 0;
+    CAmount maxfeerate = 0;
+    CAmount minfee = MAX_MONEY;
+    CAmount minfeerate = MAX_MONEY;
+    CAmount total_out = 0;
+    CAmount totalfee = 0;
+    int64_t inputs = 0;
+    int64_t maxtxsize = 0;
+    int64_t mintxsize = MAX_BLOCK_SERIALIZED_SIZE;
+    int64_t outputs = 0;
+    int64_t swtotal_size = 0;
+    int64_t swtotal_weight = 0;
+    int64_t swtxs = 0;
+    int64_t total_size = 0;
+    int64_t total_weight = 0;
+    int64_t utxo_size_inc = 0;
+    std::vector<CAmount> fee_array;
+    std::vector<CAmount> feerate_array;
+    std::vector<int64_t> txsize_array;
+
+    for (const auto& tx : block.vtx) {
+        outputs += tx->vout.size();
+
+        CAmount tx_total_out = 0;
+        if (loop_outputs) {
+            for (const CTxOut& out : tx->vout) {
+                tx_total_out += out.nValue;
+                utxo_size_inc += GetSerializeSize(out, SER_NETWORK, PROTOCOL_VERSION) + PER_UTXO_OVERHEAD;
+            }
+        }
+
+        if (tx->IsCoinBase()) {
+            continue;
+        }
+
+        inputs += tx->vin.size(); // Don't count coinbase's fake input
+        total_out += tx_total_out; // Don't count coinbase reward
+
+        int64_t tx_size = 0;
+        if (do_calculate_size) {
+
+            tx_size = tx->GetTotalSize();
+            if (do_mediantxsize) {
+                txsize_array.push_back(tx_size);
+            }
+            maxtxsize = std::max(maxtxsize, tx_size);
+            mintxsize = std::min(mintxsize, tx_size);
+            total_size += tx_size;
+        }
+
+        int64_t weight = 0;
+        if (do_calculate_weight) {
+            weight = GetTransactionWeight(*tx);
+            total_weight += weight;
+        }
+
+        if (do_calculate_sw && tx->HasWitness()) {
+            ++swtxs;
+            swtotal_size += tx_size;
+            swtotal_weight += weight;
+        }
+
+        if (loop_inputs) {
+
+            if (!g_txindex) {
+                throw JSONRPCError(RPC_INVALID_PARAMETER, "One or more of the selected stats requires -txindex enabled");
+            }
+            CAmount tx_total_in = 0;
+            for (const CTxIn& in : tx->vin) {
+                CTransactionRef tx_in;
+                uint256 hashBlock;
+                if (!GetTransaction(in.prevout.hash, tx_in, Params().GetConsensus(), hashBlock, false)) {
+                    throw JSONRPCError(RPC_INTERNAL_ERROR, std::string("Unexpected internal error (tx index seems corrupt)"));
+                }
+
+                CTxOut prevoutput = tx_in->vout[in.prevout.n];
+
+                tx_total_in += prevoutput.nValue;
+                utxo_size_inc -= GetSerializeSize(prevoutput, SER_NETWORK, PROTOCOL_VERSION) + PER_UTXO_OVERHEAD;
+            }
+
+            CAmount txfee = tx_total_in - tx_total_out;
+            assert(MoneyRange(txfee));
+            if (do_medianfee) {
+                fee_array.push_back(txfee);
+            }
+            maxfee = std::max(maxfee, txfee);
+            minfee = std::min(minfee, txfee);
+            totalfee += txfee;
+
+            // New feerate uses satoshis per virtual byte instead of per serialized byte
+            CAmount feerate = weight ? (txfee * WITNESS_SCALE_FACTOR) / weight : 0;
+            if (do_medianfeerate) {
+                feerate_array.push_back(feerate);
+            }
+            maxfeerate = std::max(maxfeerate, feerate);
+            minfeerate = std::min(minfeerate, feerate);
+        }
+    }
+
+    UniValue ret_all(UniValue::VOBJ);
+    ret_all.pushKV("avgfee", (block.vtx.size() > 1) ? totalfee / (block.vtx.size() - 1) : 0);
+    ret_all.pushKV("avgfeerate", total_weight ? (totalfee * WITNESS_SCALE_FACTOR) / total_weight : 0); // Unit: sat/vbyte
+    ret_all.pushKV("avgtxsize", (block.vtx.size() > 1) ? total_size / (block.vtx.size() - 1) : 0);
+    ret_all.pushKV("blockhash", pindex->GetBlockHash().GetHex());
+    ret_all.pushKV("height", (int64_t)pindex->nHeight);
+    ret_all.pushKV("ins", inputs);
+    ret_all.pushKV("maxfee", maxfee);
+    ret_all.pushKV("maxfeerate", maxfeerate);
+    ret_all.pushKV("maxtxsize", maxtxsize);
+    ret_all.pushKV("medianfee", CalculateTruncatedMedian(fee_array));
+    ret_all.pushKV("medianfeerate", CalculateTruncatedMedian(feerate_array));
+    ret_all.pushKV("mediantime", pindex->GetMedianTimePast());
+    ret_all.pushKV("mediantxsize", CalculateTruncatedMedian(txsize_array));
+    ret_all.pushKV("minfee", (minfee == MAX_MONEY) ? 0 : minfee);
+    ret_all.pushKV("minfeerate", (minfeerate == MAX_MONEY) ? 0 : minfeerate);
+    ret_all.pushKV("mintxsize", mintxsize == MAX_BLOCK_SERIALIZED_SIZE ? 0 : mintxsize);
+    ret_all.pushKV("outs", outputs);
+    ret_all.pushKV("subsidy", GetBlockSubsidy(pindex->nHeight, Params().GetConsensus()));
+    ret_all.pushKV("swtotal_size", swtotal_size);
+    ret_all.pushKV("swtotal_weight", swtotal_weight);
+    ret_all.pushKV("swtxs", swtxs);
+    ret_all.pushKV("time", pindex->GetBlockTime());
+    ret_all.pushKV("total_out", total_out);
+    ret_all.pushKV("total_size", total_size);
+    ret_all.pushKV("total_weight", total_weight);
+    ret_all.pushKV("totalfee", totalfee);
+    ret_all.pushKV("txs", (int64_t)block.vtx.size());
+    ret_all.pushKV("utxo_increase", outputs - inputs);
+    ret_all.pushKV("utxo_size_inc", utxo_size_inc);
+
+    if (do_all) {
+        return ret_all;
+    }
+
+    UniValue ret(UniValue::VOBJ);
+    for (const std::string& stat : stats) {
+        const UniValue& value = ret_all[stat];
+        if (value.isNull()) {
+            throw JSONRPCError(RPC_INVALID_PARAMETER, strprintf("Invalid selected statistic %s", stat));
+        }
+        ret.pushKV(stat, value);
+    }
+    return ret;
+}
+
 static UniValue savemempool(const JSONRPCRequest& request)
 {
     if (request.fHelp || request.params.size() != 0) {
@@ -1651,6 +1931,7 @@ static const CRPCCommand commands[] =
   //  --------------------- ------------------------  -----------------------  ----------
     { "blockchain",         "getblockchaininfo",      &getblockchaininfo,      {} },
     { "blockchain",         "getchaintxstats",        &getchaintxstats,        {"nblocks", "blockhash"} },
+    { "blockchain",         "getblockstats",          &getblockstats,          {"hash_or_height", "stats"} },
     { "blockchain",         "getbestblockhash",       &getbestblockhash,       {} },
     { "blockchain",         "getblockcount",          &getblockcount,          {} },
     { "blockchain",         "getblock",               &getblock,               {"blockhash","verbosity|verbose"} },
diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index 34c41b3b6b..90a7ac9ab2 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -122,6 +122,8 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "importmulti", 1, "options" },
     { "verifychain", 0, "checklevel" },
     { "verifychain", 1, "nblocks" },
+    { "getblockstats", 0, "hash_or_height" },
+    { "getblockstats", 1, "stats" },
     { "pruneblockchain", 0, "height" },
     { "keypoolrefill", 0, "newsize" },
     { "getrawmempool", 0, "verbose" },