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authorAlex Morcos <morcos@chaincode.com>2017-07-06 14:00:46 -0400
committerAlex Morcos <morcos@chaincode.com>2017-07-17 13:40:30 -0400
commitf4d00e63f7951469c840edede3f675d07249f62a (patch)
treeb18d0d106aa0928780b64c0d3e23425800024537 /src/wallet
parentb1385852ef2ba45fd6926d75497646debf79e686 (diff)
Add a discard_rate
Any change output which would be dust at the discard_rate you are willing to discard completely and add to fee (as well as continuing to pay the fee that would have been needed for creating the change).
Diffstat (limited to 'src/wallet')
-rw-r--r--src/wallet/wallet.cpp31
-rw-r--r--src/wallet/wallet.h3
2 files changed, 32 insertions, 2 deletions
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 13da7bb2c2..e230ee0eb0 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -57,6 +57,8 @@ CFeeRate CWallet::minTxFee = CFeeRate(DEFAULT_TRANSACTION_MINFEE);
*/
CFeeRate CWallet::fallbackFee = CFeeRate(DEFAULT_FALLBACK_FEE);
+CFeeRate CWallet::m_discard_rate = CFeeRate(DEFAULT_DISCARD_FEE);
+
const uint256 CMerkleTx::ABANDON_HASH(uint256S("0000000000000000000000000000000000000000000000000000000000000001"));
/** @defgroup mapWallet
@@ -2501,6 +2503,17 @@ bool CWallet::FundTransaction(CMutableTransaction& tx, CAmount& nFeeRet, int& nC
return true;
}
+static CFeeRate GetDiscardRate(const CBlockPolicyEstimator& estimator)
+{
+ unsigned int highest_target = estimator.HighestTargetTracked(FeeEstimateHorizon::LONG_HALFLIFE);
+ CFeeRate discard_rate = estimator.estimateSmartFee(highest_target, nullptr /* FeeCalculation */, false /* conservative */);
+ // Don't let discard_rate be greater than longest possible fee estimate if we get a valid fee estimate
+ discard_rate = (discard_rate == CFeeRate(0)) ? CWallet::m_discard_rate : std::min(discard_rate, CWallet::m_discard_rate);
+ // Discard rate must be at least dustRelayFee
+ discard_rate = std::max(discard_rate, ::dustRelayFee);
+ return discard_rate;
+}
+
bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletTx& wtxNew, CReserveKey& reservekey, CAmount& nFeeRet,
int& nChangePosInOut, std::string& strFailReason, const CCoinControl& coin_control, bool sign)
{
@@ -2600,6 +2613,7 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
CTxOut change_prototype_txout(0, scriptChange);
size_t change_prototype_size = GetSerializeSize(change_prototype_txout, SER_DISK, 0);
+ CFeeRate discard_rate = GetDiscardRate(::feeEstimator);
nFeeRet = 0;
bool pick_new_inputs = true;
CAmount nValueIn = 0;
@@ -2667,7 +2681,7 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
// Never create dust outputs; if we would, just
// add the dust to the fee.
- if (IsDust(newTxOut, ::dustRelayFee))
+ if (IsDust(newTxOut, discard_rate))
{
nChangePosInOut = -1;
nFeeRet += nChange;
@@ -2747,7 +2761,7 @@ bool CWallet::CreateTransaction(const std::vector<CRecipient>& vecSend, CWalletT
// (because of reduced tx size) and so we should add a
// change output. Only try this once.
CAmount fee_needed_for_change = GetMinimumFee(change_prototype_size, coin_control, ::mempool, ::feeEstimator, nullptr);
- CAmount minimum_value_for_change = GetDustThreshold(change_prototype_txout, ::dustRelayFee);
+ CAmount minimum_value_for_change = GetDustThreshold(change_prototype_txout, discard_rate);
CAmount max_excess_fee = fee_needed_for_change + minimum_value_for_change;
if (nFeeRet > nFeeNeeded + max_excess_fee && nChangePosInOut == -1 && nSubtractFeeFromAmount == 0 && pick_new_inputs) {
pick_new_inputs = false;
@@ -3788,6 +3802,9 @@ std::string CWallet::GetWalletHelpString(bool showDebug)
strUsage += HelpMessageOpt("-keypool=<n>", strprintf(_("Set key pool size to <n> (default: %u)"), DEFAULT_KEYPOOL_SIZE));
strUsage += HelpMessageOpt("-fallbackfee=<amt>", strprintf(_("A fee rate (in %s/kB) that will be used when fee estimation has insufficient data (default: %s)"),
CURRENCY_UNIT, FormatMoney(DEFAULT_FALLBACK_FEE)));
+ strUsage += HelpMessageOpt("-discardfee=<amt>", strprintf(_("The fee rate (in %s/kB) used to discard change (to fee) if it would be dust at this fee rate (default: %s) "
+ "Note: We will always discard up to the dust relay fee and a discard fee above that is limited by the longest target fee estimate"),
+ CURRENCY_UNIT, FormatMoney(DEFAULT_DISCARD_FEE)));
strUsage += HelpMessageOpt("-mintxfee=<amt>", strprintf(_("Fees (in %s/kB) smaller than this are considered zero fee for transaction creation (default: %s)"),
CURRENCY_UNIT, FormatMoney(DEFAULT_TRANSACTION_MINFEE)));
strUsage += HelpMessageOpt("-paytxfee=<amt>", strprintf(_("Fee (in %s/kB) to add to transactions you send (default: %s)"),
@@ -4113,6 +4130,16 @@ bool CWallet::ParameterInteraction()
_("This is the transaction fee you may pay when fee estimates are not available."));
CWallet::fallbackFee = CFeeRate(nFeePerK);
}
+ if (IsArgSet("-discardfee"))
+ {
+ CAmount nFeePerK = 0;
+ if (!ParseMoney(GetArg("-discardfee", ""), nFeePerK))
+ return InitError(strprintf(_("Invalid amount for -discardfee=<amount>: '%s'"), GetArg("-discardfee", "")));
+ if (nFeePerK > HIGH_TX_FEE_PER_KB)
+ InitWarning(AmountHighWarn("-discardfee") + " " +
+ _("This is the transaction fee you may discard if change is smaller than dust at this level"));
+ CWallet::m_discard_rate = CFeeRate(nFeePerK);
+ }
if (IsArgSet("-paytxfee"))
{
CAmount nFeePerK = 0;
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index b716e46a7d..a7fef8a802 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -45,6 +45,8 @@ static const unsigned int DEFAULT_KEYPOOL_SIZE = 100;
static const CAmount DEFAULT_TRANSACTION_FEE = 0;
//! -fallbackfee default
static const CAmount DEFAULT_FALLBACK_FEE = 20000;
+//! -m_discard_rate default
+static const CAmount DEFAULT_DISCARD_FEE = 10000;
//! -mintxfee default
static const CAmount DEFAULT_TRANSACTION_MINFEE = 1000;
//! minimum recommended increment for BIP 125 replacement txs
@@ -965,6 +967,7 @@ public:
static CFeeRate minTxFee;
static CFeeRate fallbackFee;
+ static CFeeRate m_discard_rate;
/**
* Estimate the minimum fee considering user set parameters
* and the required fee