rpc: use cachedEstimates in estimatefeewithmempool

willcl-ark · Feb 20, 2024 · 338d84b · 338d84b
1 parent c4d4bc7
commit 338d84b
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Showing 3 changed files with 29 additions and 16 deletions.
diff --git a/src/policy/mempool_fees.cpp b/src/policy/mempool_fees.cpp
@@ -13,8 +13,10 @@ using node::GetCustomBlockFeeRateHistogram;
 
 MemPoolPolicyEstimator::MemPoolPolicyEstimator() {}
 
-CFeeRate MemPoolPolicyEstimator::EstimateFeeWithMemPool(Chainstate& chainstate, const CTxMemPool& mempool, unsigned int confTarget, std::string& err_message) const
+CFeeRate MemPoolPolicyEstimator::EstimateFeeWithMemPool(Chainstate& chainstate, const CTxMemPool& mempool, unsigned int confTarget, const bool force, std::string& err_message) const
 {
+    std::optional<CFeeRate> cached_fee{std::nullopt};
+    CFeeRate fee_rate{0};
 
     if (confTarget > MAX_CONF_TARGET) {
         err_message = strprintf("Confirmation target %s is above maximum limit of %s, mempool conditions might change and estimates above %s are unreliable.\n", confTarget, MAX_CONF_TARGET, MAX_CONF_TARGET);
@@ -25,18 +27,26 @@ CFeeRate MemPoolPolicyEstimator::EstimateFeeWithMemPool(Chainstate& chainstate,
         err_message = "Mempool did not finish loading, can't get accurate fee rate estimate.";
         return CFeeRate(0);
     }
-
-    std::map<CFeeRate, uint64_t> mempool_fee_stats;
-    size_t target_weight = confTarget * DEFAULT_BLOCK_MAX_WEIGHT;
-    {
-        mempool_fee_stats = GetCustomBlockFeeRateHistogram(chainstate, &mempool, target_weight);
+    // Try the cache if not forced
+    if (!force) {
+        cached_fee = cache.get(confTarget);
     }
 
-    if (mempool_fee_stats.empty()) {
-        err_message = "No transactions available in the mempool yet.";
-        return CFeeRate(0); // Return an appropriate default value (no txs in the mempool)
+    if (!cached_fee) {
+        // Run block builder and update cache
+        std::map<CFeeRate, uint64_t> mempool_fee_stats;
+        size_t target_weight = confTarget * DEFAULT_BLOCK_MAX_WEIGHT;
+        mempool_fee_stats = GetCustomBlockFeeRateHistogram(chainstate, &mempool, target_weight);
+        if (mempool_fee_stats.empty()) {
+            err_message = "No transactions available in the mempool yet.";
+            return CFeeRate(0); // Return an appropriate default value (no txs in the mempool)
+        }
+        cache.update(mempool_fee_stats);
+        fee_rate = EstimateBlockFeeRate(mempool_fee_stats, confTarget, target_weight);
+    } else {
+        // Use the cached value
+        fee_rate = *cached_fee;
     }
-    auto fee_rate = EstimateBlockFeeRate(mempool_fee_stats, confTarget, target_weight);
 
     if (fee_rate == CFeeRate(0)) {
         err_message = "Insufficient mempool transactions to perform an estimate.";

diff --git a/src/policy/mempool_fees.h b/src/policy/mempool_fees.h
@@ -89,7 +89,7 @@ class MemPoolPolicyEstimator
      * @param[out] err_message  optional error message.
      * @return The estimated fee rate.
      */
-    CFeeRate EstimateFeeWithMemPool(Chainstate& chainstate, const CTxMemPool& mempool, unsigned int confTarget, std::string& err_message) const;
+    CFeeRate EstimateFeeWithMemPool(Chainstate& chainstate, const CTxMemPool& mempool, unsigned int confTarget, const bool force, std::string& err_message) const;
 
 private:
     mutable CachedEstimates cache;

diff --git a/src/rpc/fees.cpp b/src/rpc/fees.cpp
@@ -101,15 +101,17 @@ static RPCHelpMan estimatesmartfee()
     };
 }
 
-static RPCHelpMan estimatesfeewithmempool()
+static RPCHelpMan estimatefeewithmempool()
 {
     return RPCHelpMan{
-        "estimatesfeewithmempool",
+        "estimatefeewithmempool",
         "\nEstimates the approximate fee per kilobyte needed for a transaction to begin\n"
         "confirmation within conf_target blocks if possible Uses virtual transaction size as defined\n"
-        "in BIP 141 (witness data is discounted).\n",
+        "in BIP 141 (witness data is discounted). By default caches values for 30 seconds to avoid\n"
+        "repeatedly running expensive block-building algorithm.\n",
         {
             {"conf_target", RPCArg::Type::NUM, RPCArg::Optional::NO, "Confirmation target in blocks"},
+            {"force", RPCArg::Type::BOOL, RPCArg::Default{false}, "Force run block-building algorithm, bypassing any cached values."},
         },
         RPCResult{
             RPCResult::Type::OBJ, "", "", {
@@ -126,11 +128,12 @@ static RPCHelpMan estimatesfeewithmempool()
             ChainstateManager& chainman = EnsureChainman(node);
             Chainstate& chainstate = chainman.ActiveChainstate();
             const unsigned int conf_target = request.params[0].getInt<unsigned int>();
+            const bool force = request.params[1].get_bool();
             CFeeRate feeRate;
             std::string err_message;
             {
                 LOCK2(cs_main, mempool.cs);
-                feeRate = fee_estimator.EstimateFeeWithMemPool(chainstate, mempool, conf_target, err_message);
+                feeRate = fee_estimator.EstimateFeeWithMemPool(chainstate, mempool, conf_target, force, err_message);
             }
             UniValue result(UniValue::VOBJ);
             UniValue errors(UniValue::VARR);
@@ -271,7 +274,7 @@ void RegisterFeeRPCCommands(CRPCTable& t)
 {
     static const CRPCCommand commands[]{
         {"util", &estimatesmartfee},
-        {"util", &estimatesfeewithmempool},
+        {"util", &estimatefeewithmempool},
         {"hidden", &estimaterawfee},
     };
     for (const auto& c : commands) {