Track transaction packages in CTxMemPoolEntry

Associate with each CTxMemPoolEntry all the size/fees of descendant
mempool transactions.  Sort mempool by max(feerate of entry, feerate
of descendants).  Update statistics on-the-fly as transactions enter
or leave the mempool.

Also add ancestor and descendant limiting, so that transactions can
be rejected if the number or size of unconfirmed ancestors exceeds
a target, or if adding a transaction would cause some other mempool
entry to have too many (or too large) a set of unconfirmed in-
mempool descendants.

1 files changed, 139 insertions, 10 deletions

diff --git a/src/test/mempool_tests.cpp b/src/test/mempool_tests.cpp
index 7f82a61bf3..5bf1e98e8f 100644
--- a/src/test/mempool_tests.cpp
+++ b/src/test/mempool_tests.cpp
@@ -9,6 +9,7 @@
 
 #include <boost/test/unit_test.hpp>
 #include <list>
+#include <vector>
 
 BOOST_FIXTURE_TEST_SUITE(mempool_tests, TestingSetup)
 
@@ -100,6 +101,16 @@ BOOST_AUTO_TEST_CASE(MempoolRemoveTest)
     removed.clear();
 }
 
+void CheckSort(CTxMemPool &pool, std::vector<std::string> &sortedOrder)
+{
+    BOOST_CHECK_EQUAL(pool.size(), sortedOrder.size());
+    CTxMemPool::indexed_transaction_set::nth_index<1>::type::iterator it = pool.mapTx.get<1>().begin();
+    int count=0;
+    for (; it != pool.mapTx.get<1>().end(); ++it, ++count) {
+        BOOST_CHECK_EQUAL(it->GetTx().GetHash().ToString(), sortedOrder[count]);
+    }
+}
+
 BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
 {
     CTxMemPool pool(CFeeRate(0));
@@ -138,18 +149,136 @@ BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
     tx5.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx5.vout[0].nValue = 11 * COIN;
     pool.addUnchecked(tx5.GetHash(), CTxMemPoolEntry(tx5, 10000LL, 1, 10.0, 1, true));
-
-    // there should be 4 transactions in the mempool
     BOOST_CHECK_EQUAL(pool.size(), 5);
 
-    // Check the fee-rate index is in order, should be tx2, tx4, tx1, tx5, tx3
-    CTxMemPool::indexed_transaction_set::nth_index<1>::type::iterator it = pool.mapTx.get<1>().begin();
-    BOOST_CHECK_EQUAL(it++->GetTx().GetHash().ToString(), tx2.GetHash().ToString());
-    BOOST_CHECK_EQUAL(it++->GetTx().GetHash().ToString(), tx4.GetHash().ToString());
-    BOOST_CHECK_EQUAL(it++->GetTx().GetHash().ToString(), tx1.GetHash().ToString());
-    BOOST_CHECK_EQUAL(it++->GetTx().GetHash().ToString(), tx5.GetHash().ToString());
-    BOOST_CHECK_EQUAL(it++->GetTx().GetHash().ToString(), tx3.GetHash().ToString());
-    BOOST_CHECK(it == pool.mapTx.get<1>().end());
+    std::vector<std::string> sortedOrder;
+    sortedOrder.resize(5);
+    sortedOrder[0] = tx2.GetHash().ToString(); // 20000
+    sortedOrder[1] = tx4.GetHash().ToString(); // 15000
+    sortedOrder[2] = tx1.GetHash().ToString(); // 10000
+    sortedOrder[3] = tx5.GetHash().ToString(); // 10000
+    sortedOrder[4] = tx3.GetHash().ToString(); // 0
+    CheckSort(pool, sortedOrder);
+
+    /* low fee but with high fee child */
+    /* tx6 -> tx7 -> tx8, tx9 -> tx10 */
+    CMutableTransaction tx6 = CMutableTransaction();
+    tx6.vout.resize(1);
+    tx6.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
+    tx6.vout[0].nValue = 20 * COIN;
+    pool.addUnchecked(tx6.GetHash(), CTxMemPoolEntry(tx6, 0LL, 1, 10.0, 1, true));
+    BOOST_CHECK_EQUAL(pool.size(), 6);
+    // Check that at this point, tx6 is sorted low
+    sortedOrder.push_back(tx6.GetHash().ToString());
+    CheckSort(pool, sortedOrder);
+
+    CTxMemPool::setEntries setAncestors;
+    setAncestors.insert(pool.mapTx.find(tx6.GetHash()));
+    CMutableTransaction tx7 = CMutableTransaction();
+    tx7.vin.resize(1);
+    tx7.vin[0].prevout = COutPoint(tx6.GetHash(), 0);
+    tx7.vin[0].scriptSig = CScript() << OP_11;
+    tx7.vout.resize(2);
+    tx7.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
+    tx7.vout[0].nValue = 10 * COIN;
+    tx7.vout[1].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
+    tx7.vout[1].nValue = 1 * COIN;
+
+    CTxMemPool::setEntries setAncestorsCalculated;
+    std::string dummy;
+    CTxMemPoolEntry entry7(tx7, 2000000LL, 1, 10.0, 1, true);
+    BOOST_CHECK_EQUAL(pool.CalculateMemPoolAncestors(entry7, setAncestorsCalculated, 100, 1000000, 1000, 1000000, dummy), true);
+    BOOST_CHECK(setAncestorsCalculated == setAncestors);
+
+    pool.addUnchecked(tx7.GetHash(), CTxMemPoolEntry(tx7, 2000000LL, 1, 10.0, 1, true), setAncestors);
+    BOOST_CHECK_EQUAL(pool.size(), 7);
+
+    // Now tx6 should be sorted higher (high fee child): tx7, tx6, tx2, ...
+    sortedOrder.erase(sortedOrder.end()-1);
+    sortedOrder.insert(sortedOrder.begin(), tx6.GetHash().ToString());
+    sortedOrder.insert(sortedOrder.begin(), tx7.GetHash().ToString());
+    CheckSort(pool, sortedOrder);
+
+    /* low fee child of tx7 */
+    CMutableTransaction tx8 = CMutableTransaction();
+    tx8.vin.resize(1);
+    tx8.vin[0].prevout = COutPoint(tx7.GetHash(), 0);
+    tx8.vin[0].scriptSig = CScript() << OP_11;
+    tx8.vout.resize(1);
+    tx8.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
+    tx8.vout[0].nValue = 10 * COIN;
+    setAncestors.insert(pool.mapTx.find(tx7.GetHash()));
+    pool.addUnchecked(tx8.GetHash(), CTxMemPoolEntry(tx8, 0LL, 2, 10.0, 1, true), setAncestors);
+
+    // Now tx8 should be sorted low, but tx6/tx both high
+    sortedOrder.push_back(tx8.GetHash().ToString());
+    CheckSort(pool, sortedOrder);
+
+    /* low fee child of tx7 */
+    CMutableTransaction tx9 = CMutableTransaction();
+    tx9.vin.resize(1);
+    tx9.vin[0].prevout = COutPoint(tx7.GetHash(), 1);
+    tx9.vin[0].scriptSig = CScript() << OP_11;
+    tx9.vout.resize(1);
+    tx9.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
+    tx9.vout[0].nValue = 1 * COIN;
+    pool.addUnchecked(tx9.GetHash(), CTxMemPoolEntry(tx9, 0LL, 3, 10.0, 1, true), setAncestors);
+
+    // tx9 should be sorted low
+    BOOST_CHECK_EQUAL(pool.size(), 9);
+    sortedOrder.push_back(tx9.GetHash().ToString());
+    CheckSort(pool, sortedOrder);
+
+    std::vector<std::string> snapshotOrder = sortedOrder;
+
+    setAncestors.insert(pool.mapTx.find(tx8.GetHash()));
+    setAncestors.insert(pool.mapTx.find(tx9.GetHash()));
+    /* tx10 depends on tx8 and tx9 and has a high fee*/
+    CMutableTransaction tx10 = CMutableTransaction();
+    tx10.vin.resize(2);
+    tx10.vin[0].prevout = COutPoint(tx8.GetHash(), 0);
+    tx10.vin[0].scriptSig = CScript() << OP_11;
+    tx10.vin[1].prevout = COutPoint(tx9.GetHash(), 0);
+    tx10.vin[1].scriptSig = CScript() << OP_11;
+    tx10.vout.resize(1);
+    tx10.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
+    tx10.vout[0].nValue = 10 * COIN;
+
+    setAncestorsCalculated.clear();
+    CTxMemPoolEntry entry10(tx10, 200000LL, 4, 10.0, 1, true);
+    BOOST_CHECK_EQUAL(pool.CalculateMemPoolAncestors(entry10, setAncestorsCalculated, 100, 1000000, 1000, 1000000, dummy), true);
+    BOOST_CHECK(setAncestorsCalculated == setAncestors);
+
+    pool.addUnchecked(tx10.GetHash(), CTxMemPoolEntry(tx10, 200000LL, 4, 10.0, 1, true), setAncestors);
+
+    /**
+     *  tx8 and tx9 should both now be sorted higher
+     *  Final order after tx10 is added:
+     *
+     *  tx7 = 2.2M (4 txs)
+     *  tx6 = 2.2M (5 txs)
+     *  tx10 = 200k (1 tx)
+     *  tx8 = 200k (2 txs)
+     *  tx9 = 200k (2 txs)
+     *  tx2 = 20000 (1)
+     *  tx4 = 15000 (1)
+     *  tx1 = 10000 (1)
+     *  tx5 = 10000 (1)
+     *  tx3 = 0 (1)
+     */
+    sortedOrder.erase(sortedOrder.end()-2, sortedOrder.end()); // take out tx8, tx9 from the end
+    sortedOrder.insert(sortedOrder.begin()+2, tx10.GetHash().ToString()); // tx10 is after tx6
+    sortedOrder.insert(sortedOrder.begin()+3, tx9.GetHash().ToString());
+    sortedOrder.insert(sortedOrder.begin()+3, tx8.GetHash().ToString());
+    CheckSort(pool, sortedOrder);
+
+    // there should be 10 transactions in the mempool
+    BOOST_CHECK_EQUAL(pool.size(), 10);
+
+    // Now try removing tx10 and verify the sort order returns to normal
+    std::list<CTransaction> removed;
+    pool.remove(pool.mapTx.find(tx10.GetHash())->GetTx(), removed, true);
+    CheckSort(pool, snapshotOrder);
 }
 
 BOOST_AUTO_TEST_SUITE_END()