Merge #9138: Improve fee estimation

44b64b9 Fix edge case with stale fee estimates (Alex Morcos)
78ae62d Add clarifying comments to fee estimation (Alex Morcos)
5fe0f47 Add extra logging to processBlock in fee estimation. (Alex Morcos)
dc008c4 Add IsCurrentForFeeEstimatation (Alex Morcos)
ebafdca Pass pointers to existing CTxMemPoolEntries to fee estimation (Alex Morcos)
d825838 Always update fee estimates on new blocks. (Alex Morcos)
6f06b26 rename bool to validFeeEstimate (Alex Morcos)
84f7ab0 Remove member variable hadNoDependencies from CTxMemPoolEntry (Alex Morcos)
60ac00d Don't track transactions at all during IBD. (Alex Morcos)
4df4479 Remove extraneous LogPrint from fee estimation (Alex Morcos)

1 files changed, 21 insertions, 3 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index f5f6851128..648fed8bc6 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -525,6 +525,18 @@ std::string FormatStateMessage(const CValidationState &state)
         state.GetRejectCode());
 }
 
+static bool IsCurrentForFeeEstimation()
+{
+    AssertLockHeld(cs_main);
+    if (IsInitialBlockDownload())
+        return false;
+    if (chainActive.Tip()->GetBlockTime() < (GetTime() - MAX_FEE_ESTIMATION_TIP_AGE))
+        return false;
+    if (chainActive.Height() < pindexBestHeader->nHeight - 1)
+        return false;
+    return true;
+}
+
 bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const CTransactionRef& ptx, bool fLimitFree,
                               bool* pfMissingInputs, int64_t nAcceptTime, bool fOverrideMempoolLimit, const CAmount& nAbsurdFee,
                               std::vector<uint256>& vHashTxnToUncache)
@@ -692,7 +704,8 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
             }
         }
 
-        CTxMemPoolEntry entry(ptx, nFees, nAcceptTime, dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOpsCost, lp);
+        CTxMemPoolEntry entry(ptx, nFees, nAcceptTime, dPriority, chainActive.Height(),
+                              inChainInputValue, fSpendsCoinbase, nSigOpsCost, lp);
         unsigned int nSize = entry.GetTxSize();
 
         // Check that the transaction doesn't have an excessive number of
@@ -940,8 +953,13 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
         }
         pool.RemoveStaged(allConflicting, false);
 
+        // This transaction should only count for fee estimation if
+        // the node is not behind and it is not dependent on any other
+        // transactions in the mempool
+        bool validForFeeEstimation = IsCurrentForFeeEstimation() && pool.HasNoInputsOf(tx);
+
         // Store transaction in memory
-        pool.addUnchecked(hash, entry, setAncestors, !IsInitialBlockDownload());
+        pool.addUnchecked(hash, entry, setAncestors, validForFeeEstimation);
 
         // trim mempool and check if tx was trimmed
         if (!fOverrideMempoolLimit) {
@@ -2206,7 +2224,7 @@ bool static ConnectTip(CValidationState& state, const CChainParams& chainparams,
     int64_t nTime5 = GetTimeMicros(); nTimeChainState += nTime5 - nTime4;
     LogPrint("bench", "  - Writing chainstate: %.2fms [%.2fs]\n", (nTime5 - nTime4) * 0.001, nTimeChainState * 0.000001);
     // Remove conflicting transactions from the mempool.;
-    mempool.removeForBlock(blockConnecting.vtx, pindexNew->nHeight, !IsInitialBlockDownload());
+    mempool.removeForBlock(blockConnecting.vtx, pindexNew->nHeight);
     // Update chainActive & related variables.
     UpdateTip(pindexNew, chainparams);