Merge #8448: Store mempool and prioritization data to disk

582068a Add mempool.dat to doc/files.md (Pieter Wuille)
3f78562 Add DumpMempool and LoadMempool (Pieter Wuille)
ced7c94 Add AcceptToMemoryPoolWithTime function (Pieter Wuille)
c3efb58 Add feedelta to TxMempoolInfo (Pieter Wuille)

doc/files.md

@@ -10,6 +10,7 @@
 * db.log: wallet database log file
 * debug.log: contains debug information and general logging generated by dashd or dash-qt
 * fee_estimates.dat: stores statistics used to estimate minimum transaction fees and priorities required for confirmation; since 0.10.0
+* mempool.dat: dump of the mempool's transactions; since 0.14.0.
 * governance.dat: stores data for governance obgects
 * masternode.conf: contains configuration settings for remote masternodes
 * mncache.dat: stores data for masternode list

src/init.cpp

@@ -250,6 +250,7 @@ void PrepareShutdown()
     flatdb4.Dump(netfulfilledman);
 
     UnregisterNodeSignals(GetNodeSignals());
+    DumpMempool();
 
     if (fFeeEstimatesInitialized)
     {
@@ -760,6 +761,8 @@ void ThreadImport(std::vector<boost::filesystem::path> vImportFiles)
         LogPrintf("Stopping after block import\n");
         StartShutdown();
     }
+
+    LoadMempool();
 }
 
 /** Sanity checks

src/txmempool.cpp

@@ -967,6 +967,10 @@ void CTxMemPool::queryHashes(vector<uint256>& vtxid)
     }
 }
 
+static TxMempoolInfo GetInfo(CTxMemPool::indexed_transaction_set::const_iterator it) {
+    return TxMempoolInfo{it->GetSharedTx(), it->GetTime(), CFeeRate(it->GetFee(), it->GetTxSize()), it->GetModifiedFee() - it->GetFee()};
+}
+
 std::vector<TxMempoolInfo> CTxMemPool::infoAll() const
 {
     LOCK(cs);
@@ -975,7 +979,7 @@ std::vector<TxMempoolInfo> CTxMemPool::infoAll() const
     std::vector<TxMempoolInfo> ret;
     ret.reserve(mapTx.size());
     for (auto it : iters) {
-        ret.push_back(TxMempoolInfo{it->GetSharedTx(), it->GetTime(), CFeeRate(it->GetFee(), it->GetTxSize())});
+        ret.push_back(GetInfo(it));
     }
 
     return ret;
@@ -996,7 +1000,7 @@ TxMempoolInfo CTxMemPool::info(const uint256& hash) const
     indexed_transaction_set::const_iterator i = mapTx.find(hash);
     if (i == mapTx.end())
         return TxMempoolInfo();
-    return TxMempoolInfo{i->GetSharedTx(), i->GetTime(), CFeeRate(i->GetFee(), i->GetTxSize())};
+    return GetInfo(i);
 }
 
 CFeeRate CTxMemPool::estimateFee(int nBlocks) const

src/txmempool.h

@@ -329,6 +329,9 @@ struct TxMempoolInfo
 
     /** Feerate of the transaction. */
     CFeeRate feeRate;
+
+    /** The fee delta. */
+    int64_t nFeeDelta;
 };
 
 class SaltedTxidHasher

src/validation.cpp

@@ -566,7 +566,7 @@ std::string FormatStateMessage(const CValidationState &state)
 }
 
 bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const CTransaction& tx, bool fLimitFree,
-                              bool* pfMissingInputs, bool fOverrideMempoolLimit, const CAmount& nAbsurdFee,
+                              bool* pfMissingInputs, int64_t nAcceptTime, bool fOverrideMempoolLimit, const CAmount& nAbsurdFee,
                               std::vector<COutPoint>& coins_to_uncache, bool fDryRun)
 {
     const uint256 hash = tx.GetHash();
@@ -760,7 +760,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
             }
         }
 
-        CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOps, lp);
+        CTxMemPoolEntry entry(tx, nFees, nAcceptTime, dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue, fSpendsCoinbase, nSigOps, lp);
         unsigned int nSize = entry.GetTxSize();
 
         // Check that the transaction doesn't have an excessive number of
@@ -1023,11 +1023,11 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
     return true;
 }
 
-bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
+bool AcceptToMemoryPoolWithTime(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
-                        bool* pfMissingInputs, bool fOverrideMempoolLimit, const CAmount nAbsurdFee, bool fDryRun)
+                        bool* pfMissingInputs, int64_t nAcceptTime, bool fOverrideMempoolLimit, const CAmount nAbsurdFee, bool fDryRun)
 {
     std::vector<COutPoint> coins_to_uncache;
-    bool res = AcceptToMemoryPoolWorker(pool, state, tx, fLimitFree, pfMissingInputs, fOverrideMempoolLimit, nAbsurdFee, coins_to_uncache, fDryRun);
+    bool res = AcceptToMemoryPoolWorker(pool, state, tx, fLimitFree, pfMissingInputs, nAcceptTime, fOverrideMempoolLimit, nAbsurdFee, coins_to_uncache, fDryRun);
     if (!res || fDryRun) {
         if(!res) LogPrint("mempool", "%s: %s %s\n", __func__, tx.GetHash().ToString(), state.GetRejectReason());
         BOOST_FOREACH(const COutPoint& hashTx, coins_to_uncache)
@@ -1039,6 +1039,12 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
     return res;
 }
 
+bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
+                        bool* pfMissingInputs, bool fOverrideMempoolLimit, const CAmount nAbsurdFee, bool fDryRun)
+{
+    return AcceptToMemoryPoolWithTime(pool, state, tx, fLimitFree, pfMissingInputs, GetTime(), fOverrideMempoolLimit, nAbsurdFee, fDryRun);
+}
+
 bool GetTimestampIndex(const unsigned int &high, const unsigned int &low, std::vector<uint256> &hashes)
 {
     if (!fTimestampIndex)
@@ -4496,6 +4502,119 @@ int VersionBitsTipStateSinceHeight(const Consensus::Params& params, Consensus::D
     return VersionBitsStateSinceHeight(chainActive.Tip(), params, pos, versionbitscache);
 }
 
+static const uint64_t MEMPOOL_DUMP_VERSION = 1;
+
+bool LoadMempool(void)
+{
+    int64_t nExpiryTimeout = GetArg("-mempoolexpiry", DEFAULT_MEMPOOL_EXPIRY) * 60 * 60;
+    FILE* filestr = fopen((GetDataDir() / "mempool.dat").string().c_str(), "r");
+    CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
+    if (file.IsNull()) {
+        LogPrintf("Failed to open mempool file from disk. Continuing anyway.\n");
+        return false;
+    }
+
+    int64_t count = 0;
+    int64_t skipped = 0;
+    int64_t failed = 0;
+    int64_t nNow = GetTime();
+
+    try {
+        uint64_t version;
+        file >> version;
+        if (version != MEMPOOL_DUMP_VERSION) {
+            return false;
+        }
+        uint64_t num;
+        file >> num;
+        double prioritydummy = 0;
+        while (num--) {
+            CTransaction tx;
+            int64_t nTime;
+            int64_t nFeeDelta;
+            file >> tx;
+            file >> nTime;
+            file >> nFeeDelta;
+
+            CAmount amountdelta = nFeeDelta;
+            if (amountdelta) {
+                mempool.PrioritiseTransaction(tx.GetHash(), tx.GetHash().ToString(), prioritydummy, amountdelta);
+            }
+            CValidationState state;
+            if (nTime + nExpiryTimeout > nNow) {
+                LOCK(cs_main);
+                AcceptToMemoryPoolWithTime(mempool, state, tx, true, NULL, nTime);
+                if (state.IsValid()) {
+                    ++count;
+                } else {
+                    ++failed;
+                }
+            } else {
+                ++skipped;
+            }
+        }
+        std::map<uint256, CAmount> mapDeltas;
+        file >> mapDeltas;
+
+        for (const auto& i : mapDeltas) {
+            mempool.PrioritiseTransaction(i.first, i.first.ToString(), prioritydummy, i.second);
+        }
+    } catch (const std::exception& e) {
+        LogPrintf("Failed to deserialize mempool data on disk: %s. Continuing anyway.\n", e.what());
+        return false;
+    }
+
+    LogPrintf("Imported mempool transactions from disk: %i successes, %i failed, %i expired\n", count, failed, skipped);
+    return true;
+}
+
+void DumpMempool(void)
+{
+    int64_t start = GetTimeMicros();
+
+    std::map<uint256, CAmount> mapDeltas;
+    std::vector<TxMempoolInfo> vinfo;
+
+    {
+        LOCK(mempool.cs);
+        for (const auto &i : mempool.mapDeltas) {
+            mapDeltas[i.first] = i.second.first;
+        }
+        vinfo = mempool.infoAll();
+    }
+
+    int64_t mid = GetTimeMicros();
+
+    try {
+        FILE* filestr = fopen((GetDataDir() / "mempool.dat.new").string().c_str(), "w");
+        if (!filestr) {
+            return;
+        }
+
+        CAutoFile file(filestr, SER_DISK, CLIENT_VERSION);
+
+        uint64_t version = MEMPOOL_DUMP_VERSION;
+        file << version;
+
+        file << (uint64_t)vinfo.size();
+        for (const auto& i : vinfo) {
+            file << *(i.tx);
+            file << (int64_t)i.nTime;
+            file << (int64_t)i.nFeeDelta;
+            mapDeltas.erase(i.tx->GetHash());
+        }
+
+        file << mapDeltas;
+        FileCommit(file.Get());
+        file.fclose();
+        RenameOver(GetDataDir() / "mempool.dat.new", GetDataDir() / "mempool.dat");
+        int64_t last = GetTimeMicros();
+        LogPrintf("Dumped mempool: %gs to copy, %gs to dump\n", (mid-start)*0.000001, (last-mid)*0.000001);
+    } catch (const std::exception& e) {
+        LogPrintf("Failed to dump mempool: %s. Continuing anyway.\n", e.what());
+    }
+}
+
 class CMainCleanup
 {
 public:

src/validation.h

@@ -322,6 +322,10 @@ void PruneAndFlush();
 bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
                         bool* pfMissingInputs, bool fOverrideMempoolLimit=false, const CAmount nAbsurdFee=0, bool fDryRun=false);
 
+/** (try to) add transaction to memory pool with a specified acceptance time **/
+bool AcceptToMemoryPoolWithTime(CTxMemPool& pool, CValidationState &state, const CTransaction &tx, bool fLimitFree,
+                        bool* pfMissingInputs, int64_t nAcceptTime, bool fOverrideMempoolLimit=false, const CAmount nAbsurdFee=0, bool fDryRun=false);
+
 bool GetUTXOCoin(const COutPoint& outpoint, Coin& coin);
 int GetUTXOHeight(const COutPoint& outpoint);
 int GetUTXOConfirmations(const COutPoint& outpoint);
@@ -548,4 +552,10 @@ static const unsigned int REJECT_ALREADY_KNOWN = 0x101;
 /** Transaction conflicts with a transaction already known */
 static const unsigned int REJECT_CONFLICT = 0x102;
 
+/** Dump the mempool to disk. */
+void DumpMempool();
+
+/** Load the mempool from disk. */
+bool LoadMempool();
+
 #endif // BITCOIN_VALIDATION_H