public void MempoolSizeLimitTest()
{
NodeSettings settings = NodeSettings.Default(KnownNetworks.TestNet);
var dateTimeSet = new DateTimeProviderSet();
var pool = new TxMempool(dateTimeSet, new BlockPolicyEstimator(new MempoolSettings(settings), settings.LoggerFactory, settings), settings.LoggerFactory, settings);
var entry = new TestMemPoolEntryHelper();
entry.Priority(10.0);
var tx1 = new Transaction();
tx1.AddInput(new TxIn(new Script(OpcodeType.OP_1)));
tx1.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_1, OpcodeType.OP_EQUAL)));
pool.AddUnchecked(tx1.GetHash(), entry.Fee(10000L).FromTx(tx1, pool));
var tx2 = new Transaction();
tx2.AddInput(new TxIn(new Script(OpcodeType.OP_2)));
tx2.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_2, OpcodeType.OP_EQUAL)));
pool.AddUnchecked(tx2.GetHash(), entry.Fee(5000L).FromTx(tx2, pool));
pool.TrimToSize(pool.DynamicMemoryUsage()); // should do nothing
Assert.True(pool.Exists(tx1.GetHash()));
Assert.True(pool.Exists(tx2.GetHash()));
pool.TrimToSize(pool.DynamicMemoryUsage() * 3 / 4); // should remove the lower-feerate transaction
Assert.True(pool.Exists(tx1.GetHash()));
Assert.True(!pool.Exists(tx2.GetHash()));
pool.AddUnchecked(tx2.GetHash(), entry.FromTx(tx2, pool));
var tx3 = new Transaction();
tx3.AddInput(new TxIn(new OutPoint(tx2.GetHash(), 0), new Script(OpcodeType.OP_2)));
tx3.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_3, OpcodeType.OP_EQUAL)));
pool.AddUnchecked(tx3.GetHash(), entry.Fee(20000L).FromTx(tx3, pool));
pool.TrimToSize(pool.DynamicMemoryUsage() * 3 / 4); // tx3 should pay for tx2 (CPFP)
Assert.True(!pool.Exists(tx1.GetHash()));
Assert.True(pool.Exists(tx2.GetHash()));
Assert.True(pool.Exists(tx3.GetHash()));
pool.TrimToSize(tx1.GetVirtualSize(KnownNetworks.TestNet.Consensus.Options.WitnessScaleFactor)); // mempool is limited to tx1's size in memory usage, so nothing fits
Assert.True(!pool.Exists(tx1.GetHash()));
Assert.True(!pool.Exists(tx2.GetHash()));
Assert.True(!pool.Exists(tx3.GetHash()));
var maxFeeRateRemoved = new FeeRate(25000, tx3.GetVirtualSize(KnownNetworks.TestNet.Consensus.Options.WitnessScaleFactor) + tx2.GetVirtualSize(KnownNetworks.TestNet.Consensus.Options.WitnessScaleFactor));
Assert.Equal(pool.GetMinFee(1).FeePerK, maxFeeRateRemoved.FeePerK + 1000);
var tx4 = new Transaction();
tx4.AddInput(new TxIn(new Script(OpcodeType.OP_4)));
tx4.AddInput(new TxIn(new Script(OpcodeType.OP_4)));
tx4.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_4, OpcodeType.OP_EQUAL)));
tx4.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_4, OpcodeType.OP_EQUAL)));
var tx5 = new Transaction();
tx5.AddInput(new TxIn(new OutPoint(tx4.GetHash(), 0), new Script(OpcodeType.OP_4)));
tx5.AddInput(new TxIn(new Script(OpcodeType.OP_5)));
tx5.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_5, OpcodeType.OP_EQUAL)));
tx5.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_5, OpcodeType.OP_EQUAL)));
var tx6 = new Transaction();
tx6.AddInput(new TxIn(new OutPoint(tx4.GetHash(), 0), new Script(OpcodeType.OP_4)));
tx6.AddInput(new TxIn(new Script(OpcodeType.OP_6)));
tx6.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_6, OpcodeType.OP_EQUAL)));
tx6.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_6, OpcodeType.OP_EQUAL)));
var tx7 = new Transaction();
tx7.AddInput(new TxIn(new OutPoint(tx5.GetHash(), 0), new Script(OpcodeType.OP_5)));
tx7.AddInput(new TxIn(new OutPoint(tx6.GetHash(), 0), new Script(OpcodeType.OP_6)));
tx7.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_7, OpcodeType.OP_EQUAL)));
tx7.AddOutput(new TxOut(new Money(10 * Money.COIN), new Script(OpcodeType.OP_7, OpcodeType.OP_EQUAL)));
pool.AddUnchecked(tx4.GetHash(), entry.Fee(7000L).FromTx(tx4, pool));
pool.AddUnchecked(tx5.GetHash(), entry.Fee(1000L).FromTx(tx5, pool));
pool.AddUnchecked(tx6.GetHash(), entry.Fee(1100L).FromTx(tx6, pool));
pool.AddUnchecked(tx7.GetHash(), entry.Fee(9000L).FromTx(tx7, pool));
// we only require this remove, at max, 2 txn, because its not clear what we're really optimizing for aside from that
pool.TrimToSize(pool.DynamicMemoryUsage() - 1);
Assert.True(pool.Exists(tx4.GetHash()));
Assert.True(pool.Exists(tx6.GetHash()));
Assert.True(!pool.Exists(tx7.GetHash()));
if (!pool.Exists(tx5.GetHash()))
{
pool.AddUnchecked(tx5.GetHash(), entry.Fee(1000L).FromTx(tx5, pool));
}
pool.AddUnchecked(tx7.GetHash(), entry.Fee(9000L).FromTx(tx7, pool));
pool.TrimToSize(pool.DynamicMemoryUsage() / 2); // should maximize mempool size by only removing 5/7
Assert.True(pool.Exists(tx4.GetHash()));
Assert.True(!pool.Exists(tx5.GetHash()));
Assert.True(pool.Exists(tx6.GetHash()));
Assert.True(!pool.Exists(tx7.GetHash()));
pool.AddUnchecked(tx5.GetHash(), entry.Fee(1000L).FromTx(tx5, pool));
pool.AddUnchecked(tx7.GetHash(), entry.Fee(9000L).FromTx(tx7, pool));
var vtx = new List <Transaction>();
dateTimeSet.time = 42 + TxMempool.RollingFeeHalflife;
Assert.Equal(pool.GetMinFee(1).FeePerK.Satoshi, maxFeeRateRemoved.FeePerK.Satoshi + 1000);
// ... we should keep the same min fee until we get a block
pool.RemoveForBlock(vtx, 1);
dateTimeSet.time = 42 + 2 * +TxMempool.RollingFeeHalflife;
Assert.Equal(pool.GetMinFee(1).FeePerK.Satoshi, (maxFeeRateRemoved.FeePerK.Satoshi + 1000) / 2);
// ... then feerate should drop 1/2 each halflife
dateTimeSet.time = 42 + 2 * TxMempool.RollingFeeHalflife + TxMempool.RollingFeeHalflife / 2;
Assert.Equal(pool.GetMinFee(pool.DynamicMemoryUsage() * 5 / 2).FeePerK.Satoshi, (maxFeeRateRemoved.FeePerK.Satoshi + 1000) / 4);
// ... with a 1/2 halflife when mempool is < 1/2 its target size
dateTimeSet.time = 42 + 2 * TxMempool.RollingFeeHalflife + TxMempool.RollingFeeHalflife / 2 + TxMempool.RollingFeeHalflife / 4;
Assert.Equal(pool.GetMinFee(pool.DynamicMemoryUsage() * 9 / 2).FeePerK.Satoshi, (maxFeeRateRemoved.FeePerK.Satoshi + 1000) / 8);
// ... with a 1/4 halflife when mempool is < 1/4 its target size
dateTimeSet.time = 42 + 7 * TxMempool.RollingFeeHalflife + TxMempool.RollingFeeHalflife / 2 + TxMempool.RollingFeeHalflife / 4;
Assert.Equal(1000, pool.GetMinFee(1).FeePerK.Satoshi);
// ... but feerate should never drop below 1000
dateTimeSet.time = 42 + 8 * TxMempool.RollingFeeHalflife + TxMempool.RollingFeeHalflife / 2 + TxMempool.RollingFeeHalflife / 4;
Assert.Equal(0, pool.GetMinFee(1).FeePerK);
// ... unless it has gone all the way to 0 (after getting past 1000/2)
}
