From b33d1f5ee512da5719b793b3867f75f1eea5cf52 Mon Sep 17 00:00:00 2001 From: Gavin Andresen Date: Tue, 27 May 2014 15:44:57 -0400 Subject: Use fee/priority estimates in wallet CreateTransaction The wallet now uses the mempool fee estimator with a new command-line option: -txconfirmtarget (default: 1) instead of using hard-coded fees or priorities. A new bitcoind that hasn't seen enough transactions to estimate will fall back to the old hard-coded minimum priority or transaction fee. -paytxfee option overrides -txconfirmtarget. Relaying and mining code isn't changed. For Qt, the coin control dialog now uses priority estimates to label transaction priority (instead of hard-coded constants); unspent outputs were consistently labeled with a much higher priority than is justified by the free transactions actually being accepted into blocks. I did not implement any GUI for setting -txconfirmtarget; I would suggest getting rid of the "Pay transaction fee" GUI and replace it with either "target number of confirmations" or maybe a "faster confirmation <--> lower fee" slider or select box. --- src/wallet.cpp | 44 ++++++++++++++++++++++++++++++++++++-------- 1 file changed, 36 insertions(+), 8 deletions(-) (limited to 'src/wallet.cpp') diff --git a/src/wallet.cpp b/src/wallet.cpp index daca7ac04b..d9187e4be3 100644 --- a/src/wallet.cpp +++ b/src/wallet.cpp @@ -18,6 +18,7 @@ using namespace std; // Settings CFeeRate payTxFee(DEFAULT_TRANSACTION_FEE); +unsigned int nTxConfirmTarget = 1; bool bSpendZeroConfChange = true; ////////////////////////////////////////////////////////////////////////////// @@ -1273,6 +1274,7 @@ bool CWallet::CreateTransaction(const vector >& vecSend, return false; } + wtxNew.fTimeReceivedIsTxTime = true; wtxNew.BindWallet(this); CMutableTransaction txNew; @@ -1393,19 +1395,31 @@ bool CWallet::CreateTransaction(const vector >& vecSend, } dPriority = wtxNew.ComputePriority(dPriority, nBytes); - // Check that enough fee is included - int64_t nPayFee = payTxFee.GetFee(nBytes); - bool fAllowFree = AllowFree(dPriority); - int64_t nMinFee = GetMinFee(wtxNew, nBytes, fAllowFree, GMF_SEND); - if (nFeeRet < max(nPayFee, nMinFee)) + int64_t nFeeNeeded = GetMinimumFee(nBytes, nTxConfirmTarget, mempool); + + if (nFeeRet >= nFeeNeeded) + break; // Done, enough fee included. + + // Too big to send for free? Include more fee and try again: + if (nBytes > MAX_FREE_TRANSACTION_CREATE_SIZE) { - nFeeRet = max(nPayFee, nMinFee); + nFeeRet = nFeeNeeded; continue; } - wtxNew.fTimeReceivedIsTxTime = true; + // Not enough fee: enough priority? + double dPriorityNeeded = mempool.estimatePriority(nTxConfirmTarget); + // Not enough mempool history to estimate: use hard-coded AllowFree. + if (dPriorityNeeded <= 0 && AllowFree(dPriority)) + break; - break; + // Small enough, and priority high enough, to send for free + if (dPriority >= dPriorityNeeded) + break; + + // Include more fee and try again. + nFeeRet = nFeeNeeded; + continue; } } } @@ -1513,6 +1527,20 @@ string CWallet::SendMoneyToDestination(const CTxDestination& address, int64_t nV return SendMoney(scriptPubKey, nValue, wtxNew); } +int64_t CWallet::GetMinimumFee(unsigned int nTxBytes, unsigned int nConfirmTarget, const CTxMemPool& pool) +{ + // payTxFee is user-set "I want to pay this much" + int64_t nFeeNeeded = payTxFee.GetFee(nTxBytes); + // User didn't set: use -txconfirmtarget to estimate... + if (nFeeNeeded == 0) + nFeeNeeded = pool.estimateFee(nConfirmTarget).GetFee(nTxBytes); + // ... unless we don't have enough mempool data, in which case fall + // back to a hard-coded fee + if (nFeeNeeded == 0) + nFeeNeeded = CTransaction::minTxFee.GetFee(nTxBytes); + return nFeeNeeded; +} + -- cgit v1.2.3