diff --git a/src/init.cpp b/src/init.cpp index 1e85642019..bda0e905b3 100644 --- a/src/init.cpp +++ b/src/init.cpp @@ -479,7 +479,7 @@ std::string HelpMessage(HelpMessageMode mode) if (showDebug) { strUsage += HelpMessageOpt("-acceptnonstdtxn", strprintf("Relay and mine \"non-standard\" transactions (%sdefault: %u)", "testnet/regtest only; ", defaultChainParams->RequireStandard())); strUsage += HelpMessageOpt("-incrementalrelayfee=", strprintf("Fee rate (in %s/kB) used to define cost of relay, used for mempool limiting and BIP 125 replacement. (default: %s)", CURRENCY_UNIT, FormatMoney(DEFAULT_INCREMENTAL_RELAY_FEE))); - strUsage += HelpMessageOpt("-dustrelayfee=", strprintf("Fee rate (in %s/kB) used to defined dust, the value of an output such that it will cost about 1/3 of its value in fees at this fee rate to spend it. (default: %s)", CURRENCY_UNIT, FormatMoney(DUST_RELAY_TX_FEE))); + strUsage += HelpMessageOpt("-dustrelayfee=", strprintf("Fee rate (in %s/kB) used to defined dust, the value of an output such that it will cost more than its value in fees at this fee rate to spend it. (default: %s)", CURRENCY_UNIT, FormatMoney(DUST_RELAY_TX_FEE))); } strUsage += HelpMessageOpt("-bytespersigop", strprintf(_("Equivalent bytes per sigop in transactions for relay and mining (default: %u)"), DEFAULT_BYTES_PER_SIGOP)); strUsage += HelpMessageOpt("-datacarrier", strprintf(_("Relay and mine data carrier transactions (default: %u)"), DEFAULT_ACCEPT_DATACARRIER)); diff --git a/src/policy/policy.cpp b/src/policy/policy.cpp index 9f2d623e76..605e3e0696 100644 --- a/src/policy/policy.cpp +++ b/src/policy/policy.cpp @@ -19,16 +19,18 @@ CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn) { // "Dust" is defined in terms of dustRelayFee, // which has units satoshis-per-kilobyte. - // If you'd pay more than 1/3 in fees + // If you'd pay more in fees than the value of the output // to spend something, then we consider it dust. // A typical spendable non-segwit txout is 34 bytes big, and will // need a CTxIn of at least 148 bytes to spend: // so dust is a spendable txout less than - // 546*dustRelayFee/1000 (in satoshis). + // 182*dustRelayFee/1000 (in satoshis). + // 546 satoshis at the default rate of 3000 sat/kB. // A typical spendable segwit txout is 31 bytes big, and will // need a CTxIn of at least 67 bytes to spend: // so dust is a spendable txout less than - // 294*dustRelayFee/1000 (in satoshis). + // 98*dustRelayFee/1000 (in satoshis). + // 294 satoshis at the default rate of 3000 sat/kB. if (txout.scriptPubKey.IsUnspendable()) return 0; @@ -44,7 +46,7 @@ CAmount GetDustThreshold(const CTxOut& txout, const CFeeRate& dustRelayFeeIn) nSize += (32 + 4 + 1 + 107 + 4); // the 148 mentioned above } - return 3 * dustRelayFeeIn.GetFee(nSize); + return dustRelayFeeIn.GetFee(nSize); } bool IsDust(const CTxOut& txout, const CFeeRate& dustRelayFeeIn) diff --git a/src/policy/policy.h b/src/policy/policy.h index 2c2ea9d5b8..c06820f84e 100644 --- a/src/policy/policy.h +++ b/src/policy/policy.h @@ -40,12 +40,12 @@ static const unsigned int MAX_STANDARD_P2WSH_STACK_ITEMS = 100; static const unsigned int MAX_STANDARD_P2WSH_STACK_ITEM_SIZE = 80; /** The maximum size of a standard witnessScript */ static const unsigned int MAX_STANDARD_P2WSH_SCRIPT_SIZE = 3600; -/** Min feerate for defining dust. Historically this has been the same as the +/** Min feerate for defining dust. Historically this has been based on the * minRelayTxFee, however changing the dust limit changes which transactions are * standard and should be done with care and ideally rarely. It makes sense to * only increase the dust limit after prior releases were already not creating * outputs below the new threshold */ -static const unsigned int DUST_RELAY_TX_FEE = 1000; +static const unsigned int DUST_RELAY_TX_FEE = 3000; /** * Standard script verification flags that standard transactions will comply * with. However scripts violating these flags may still be present in valid diff --git a/src/test/transaction_tests.cpp b/src/test/transaction_tests.cpp index 39f9f58604..6654634bf1 100644 --- a/src/test/transaction_tests.cpp +++ b/src/test/transaction_tests.cpp @@ -692,7 +692,7 @@ BOOST_AUTO_TEST_CASE(test_IsStandard) BOOST_CHECK(IsStandardTx(t, reason)); // Check dust with default relay fee: - CAmount nDustThreshold = 182 * dustRelayFee.GetFeePerK()/1000 * 3; + CAmount nDustThreshold = 182 * dustRelayFee.GetFeePerK()/1000; BOOST_CHECK_EQUAL(nDustThreshold, 546); // dust: t.vout[0].nValue = nDustThreshold - 1; @@ -702,13 +702,13 @@ BOOST_AUTO_TEST_CASE(test_IsStandard) BOOST_CHECK(IsStandardTx(t, reason)); // Check dust with odd relay fee to verify rounding: - // nDustThreshold = 182 * 1234 / 1000 * 3 - dustRelayFee = CFeeRate(1234); + // nDustThreshold = 182 * 3702 / 1000 + dustRelayFee = CFeeRate(3702); // dust: - t.vout[0].nValue = 672 - 1; + t.vout[0].nValue = 673 - 1; BOOST_CHECK(!IsStandardTx(t, reason)); // not dust: - t.vout[0].nValue = 672; + t.vout[0].nValue = 673; BOOST_CHECK(IsStandardTx(t, reason)); dustRelayFee = CFeeRate(DUST_RELAY_TX_FEE);