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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2017 The Starwels developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or
#include <memory>
#include <set>
#include <map>
#include <vector>
#include <utility>
#include <string>
#include <amount.h>
#include <coins.h>
#include <indirectmap.h>
#include <policy/feerate.h>
#include <primitives/transaction.h>
#include <sync.h>
#include <random.h>
#include <boost/multi_index_container.hpp>
#include <boost/multi_index/hashed_index.hpp>
#include <boost/multi_index/ordered_index.hpp>
#include <boost/multi_index/sequenced_index.hpp>
#include <boost/signals2/signal.hpp>
class CBlockIndex;
/** Fake height value used in Coin to signify they are only in the memory pool (since 0.8) */
static const uint32_t MEMPOOL_HEIGHT = 0x7FFFFFFF;
struct LockPoints
// Will be set to the blockchain height and median time past
// values that would be necessary to satisfy all relative locktime
// constraints (BIP68) of this tx given our view of block chain history
int height;
int64_t time;
// As long as the current chain descends from the highest height block
// containing one of the inputs used in the calculation, then the cached
// values are still valid even after a reorg.
CBlockIndex* maxInputBlock;
LockPoints() : height(0), time(0), maxInputBlock(nullptr) { }
class CTxMemPool;
/** \class CTxMemPoolEntry
* CTxMemPoolEntry stores data about the corresponding transaction, as well
* as data about all in-mempool transactions that depend on the transaction
* ("descendant" transactions).
* When a new entry is added to the mempool, we update the descendant state
* (nCountWithDescendants, nSizeWithDescendants, and nModFeesWithDescendants) for
* all ancestors of the newly added transaction.
class CTxMemPoolEntry
CTransactionRef tx;
CAmount nFee; //!< Cached to avoid expensive parent-transaction lookups
size_t nTxWeight; //!< ... and avoid recomputing tx weight (also used for GetTxSize())
size_t nUsageSize; //!< ... and total memory usage
int64_t nTime; //!< Local time when entering the mempool
unsigned int entryHeight; //!< Chain height when entering the mempool
bool spendsCoinbase; //!< keep track of transactions that spend a coinbase
int64_t sigOpCost; //!< Total sigop cost
int64_t feeDelta; //!< Used for determining the priority of the transaction for mining in a block
LockPoints lockPoints; //!< Track the height and time at which tx was final
// Information about descendants of this transaction that are in the
// mempool; if we remove this transaction we must remove all of these
// descendants as well.
uint64_t nCountWithDescendants; //!< number of descendant transactions
uint64_t nSizeWithDescendants; //!< ... and size
CAmount nModFeesWithDescendants; //!< ... and total fees (all including us)
// Analogous statistics for ancestor transactions
uint64_t nCountWithAncestors;
uint64_t nSizeWithAncestors;
CAmount nModFeesWithAncestors;
int64_t nSigOpCostWithAncestors;
CTxMemPoolEntry(const CTransactionRef& _tx, const CAmount& _nFee,
int64_t _nTime, unsigned int _entryHeight,
bool spendsCoinbase,
int64_t nSigOpsCost, LockPoints lp);
const CTransaction& GetTx() const { return *this->tx; }
CTransactionRef GetSharedTx() const { return this->tx; }
const CAmount& GetFee() const { return nFee; }
size_t GetTxSize() const;
size_t GetTxWeight() const { return nTxWeight; }
int64_t GetTime() const { return nTime; }
unsigned int GetHeight() const { return entryHeight; }
int64_t GetSigOpCost() const { return sigOpCost; }
int64_t GetModifiedFee() const { return nFee + feeDelta; }
size_t DynamicMemoryUsage() const { return nUsageSize; }
const LockPoints& GetLockPoints() const { return lockPoints; }
// Adjusts the descendant state.
void UpdateDescendantState(int64_t modifySize, CAmount modifyFee, int64_t modifyCount);
// Adjusts the ancestor state
void UpdateAncestorState(int64_t modifySize, CAmount modifyFee, int64_t modifyCount, int64_t modifySigOps);
// Updates the fee delta used for mining priority score, and the
// modified fees with descendants.
void UpdateFeeDelta(int64_t feeDelta);
// Update the LockPoints after a reorg
void UpdateLockPoints(const LockPoints& lp);
uint64_t GetCountWithDescendants() const { return nCountWithDescendants; }
uint64_t GetSizeWithDescendants() const { return nSizeWithDescendants; }
CAmount GetModFeesWithDescendants() const { return nModFeesWithDescendants; }
bool GetSpendsCoinbase() const { return spendsCoinbase; }
uint64_t GetCountWithAncestors() const { return nCountWithAncestors; }
uint64_t GetSizeWithAncestors() const { return nSizeWithAncestors; }
CAmount GetModFeesWithAncestors() const { return nModFeesWithAncestors; }
int64_t GetSigOpCostWithAncestors() const { return nSigOpCostWithAncestors; }
mutable size_t vTxHashesIdx; //!< Index in mempool's vTxHashes
// Helpers for modifying CTxMemPool::mapTx, which is a boost multi_index.
struct update_descendant_state
update_descendant_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount) :
modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount)
void operator() (CTxMemPoolEntry &e)
{ e.UpdateDescendantState(modifySize, modifyFee, modifyCount); }
int64_t modifySize;
CAmount modifyFee;
int64_t modifyCount;
struct update_ancestor_state
update_ancestor_state(int64_t _modifySize, CAmount _modifyFee, int64_t _modifyCount, int64_t _modifySigOpsCost) :
modifySize(_modifySize), modifyFee(_modifyFee), modifyCount(_modifyCount), modifySigOpsCost(_modifySigOpsCost)
void operator() (CTxMemPoolEntry &e)
{ e.UpdateAncestorState(modifySize, modifyFee, modifyCount, modifySigOpsCost); }
int64_t modifySize;
CAmount modifyFee;
int64_t modifyCount;
int64_t modifySigOpsCost;
struct update_fee_delta
explicit update_fee_delta(int64_t _feeDelta) : feeDelta(_feeDelta) { }
void operator() (CTxMemPoolEntry &e) { e.UpdateFeeDelta(feeDelta); }
int64_t feeDelta;
struct update_lock_points
explicit update_lock_points(const LockPoints& _lp) : lp(_lp) { }
void operator() (CTxMemPoolEntry &e) { e.UpdateLockPoints(lp); }
const LockPoints& lp;
// extracts a transaction hash from CTxMempoolEntry or CTransactionRef
struct mempoolentry_txid
typedef uint256 result_type;
result_type operator() (const CTxMemPoolEntry &entry) const
return entry.GetTx().GetHash();
result_type operator() (const CTransactionRef& tx) const
return tx->GetHash();
/** \class CompareTxMemPoolEntryByDescendantScore
* Sort an entry by max(score/size of entry's tx, score/size with all descendants).
class CompareTxMemPoolEntryByDescendantScore
bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
double a_mod_fee, a_size, b_mod_fee, b_size;
GetModFeeAndSize(a, a_mod_fee, a_size);
GetModFeeAndSize(b, b_mod_fee, b_size);
// Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
double f1 = a_mod_fee * b_size;
double f2 = a_size * b_mod_fee;
if (f1 == f2) {
return a.GetTime() >= b.GetTime();
return f1 < f2;
// Return the fee/size we're using for sorting this entry.
void GetModFeeAndSize(const CTxMemPoolEntry &a, double &mod_fee, double &size) const
// Compare feerate with descendants to feerate of the transaction, and
// return the fee/size for the max.
double f1 = (double)a.GetModifiedFee() * a.GetSizeWithDescendants();
double f2 = (double)a.GetModFeesWithDescendants() * a.GetTxSize();
if (f2 > f1) {
mod_fee = a.GetModFeesWithDescendants();
size = a.GetSizeWithDescendants();
} else {
mod_fee = a.GetModifiedFee();
size = a.GetTxSize();
/** \class CompareTxMemPoolEntryByScore
* Sort by score of entry ((fee+delta)/size) in descending order
class CompareTxMemPoolEntryByScore
bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
double f1 = (double)a.GetModifiedFee() * b.GetTxSize();
double f2 = (double)b.GetModifiedFee() * a.GetTxSize();
if (f1 == f2) {
return b.GetTx().GetHash() < a.GetTx().GetHash();
return f1 > f2;
class CompareTxMemPoolEntryByEntryTime
bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
return a.GetTime() < b.GetTime();
/** \class CompareTxMemPoolEntryByAncestorScore
* Sort an entry by min(score/size of entry's tx, score/size with all ancestors).
class CompareTxMemPoolEntryByAncestorFee
template<typename T>
bool operator()(const T& a, const T& b) const
double a_mod_fee, a_size, b_mod_fee, b_size;
GetModFeeAndSize(a, a_mod_fee, a_size);
GetModFeeAndSize(b, b_mod_fee, b_size);
// Avoid division by rewriting (a/b > c/d) as (a*d > c*b).
double f1 = a_mod_fee * b_size;
double f2 = a_size * b_mod_fee;
if (f1 == f2) {
return a.GetTx().GetHash() < b.GetTx().GetHash();
return f1 > f2;
// Return the fee/size we're using for sorting this entry.
template <typename T>
void GetModFeeAndSize(const T &a, double &mod_fee, double &size) const
// Compare feerate with ancestors to feerate of the transaction, and
// return the fee/size for the min.
double f1 = (double)a.GetModifiedFee() * a.GetSizeWithAncestors();
double f2 = (double)a.GetModFeesWithAncestors() * a.GetTxSize();
if (f1 > f2) {
mod_fee = a.GetModFeesWithAncestors();
size = a.GetSizeWithAncestors();
} else {
mod_fee = a.GetModifiedFee();
size = a.GetTxSize();
// Multi_index tag names
struct descendant_score {};
struct entry_time {};
struct ancestor_score {};
class CBlockPolicyEstimator;
* Information about a mempool transaction.
struct TxMempoolInfo
/** The transaction itself */
CTransactionRef tx;
/** Time the transaction entered the mempool. */
int64_t nTime;
/** Feerate of the transaction. */
CFeeRate feeRate;
/** The fee delta. */
int64_t nFeeDelta;
/** Reason why a transaction was removed from the mempool,
* this is passed to the notification signal.
enum class MemPoolRemovalReason {
UNKNOWN = 0, //! Manually removed or unknown reason
EXPIRY, //! Expired from mempool
SIZELIMIT, //! Removed in size limiting
REORG, //! Removed for reorganization
BLOCK, //! Removed for block
CONFLICT, //! Removed for conflict with in-block transaction
REPLACED //! Removed for replacement
class SaltedTxidHasher
/** Salt */
const uint64_t k0, k1;
size_t operator()(const uint256& txid) const {
return SipHashUint256(k0, k1, txid);
* CTxMemPool stores valid-according-to-the-current-best-chain transactions
* that may be included in the next block.
* Transactions are added when they are seen on the network (or created by the
* local node), but not all transactions seen are added to the pool. For
* example, the following new transactions will not be added to the mempool:
* - a transaction which doesn't meet the minimum fee requirements.
* - a new transaction that double-spends an input of a transaction already in
* the pool where the new transaction does not meet the Replace-By-Fee
* requirements as defined in BIP 125.
* - a non-standard transaction.
* CTxMemPool::mapTx, and CTxMemPoolEntry bookkeeping:
* mapTx is a boost::multi_index that sorts the mempool on 4 criteria:
* - transaction hash
* - feerate [we use max(feerate of tx, feerate of tx with all descendants)]
* - time in mempool
* Note: the term "descendant" refers to in-mempool transactions that depend on
* this one, while "ancestor" refers to in-mempool transactions that a given
* transaction depends on.
* In order for the feerate sort to remain correct, we must update transactions
* in the mempool when new descendants arrive. To facilitate this, we track
* the set of in-mempool direct parents and direct children in mapLinks. Within
* each CTxMemPoolEntry, we track the size and fees of all descendants.
* Usually when a new transaction is added to the mempool, it has no in-mempool
* children (because any such children would be an orphan). So in
* addUnchecked(), we:
* - update a new entry's setMemPoolParents to include all in-mempool parents
* - update the new entry's direct parents to include the new tx as a child
* - update all ancestors of the transaction to include the new tx's size/fee
* When a transaction is removed from the mempool, we must:
* - update all in-mempool parents to not track the tx in setMemPoolChildren
* - update all ancestors to not include the tx's size/fees in descendant state
* - update all in-mempool children to not include it as a parent
* These happen in UpdateForRemoveFromMempool(). (Note that when removing a
* transaction along with its descendants, we must calculate that set of
* transactions to be removed before doing the removal, or else the mempool can
* be in an inconsistent state where it's impossible to walk the ancestors of
* a transaction.)
* In the event of a reorg, the assumption that a newly added tx has no
* in-mempool children is false. In particular, the mempool is in an
* inconsistent state while new transactions are being added, because there may
* be descendant transactions of a tx coming from a disconnected block that are
* unreachable from just looking at transactions in the mempool (the linking
* transactions may also be in the disconnected block, waiting to be added).
* Because of this, there's not much benefit in trying to search for in-mempool
* children in addUnchecked(). Instead, in the special case of transactions
* being added from a disconnected block, we require the caller to clean up the
* state, to account for in-mempool, out-of-block descendants for all the
* in-block transactions by calling UpdateTransactionsFromBlock(). Note that
* until this is called, the mempool state is not consistent, and in particular
* mapLinks may not be correct (and therefore functions like
* CalculateMemPoolAncestors() and CalculateDescendants() that rely
* on them to walk the mempool are not generally safe to use).
* Computational limits:
* Updating all in-mempool ancestors of a newly added transaction can be slow,
* if no bound exists on how many in-mempool ancestors there may be.
* CalculateMemPoolAncestors() takes configurable limits that are designed to
* prevent these calculations from being too CPU intensive.
class CTxMemPool
uint32_t nCheckFrequency; //!< Value n means that n times in 2^32 we check.
unsigned int nTransactionsUpdated; //!< Used by getblocktemplate to trigger CreateNewBlock() invocation
CBlockPolicyEstimator* minerPolicyEstimator;
uint64_t totalTxSize; //!< sum of all mempool tx's virtual sizes. Differs from serialized tx size since witness data is discounted. Defined in BIP 141.
uint64_t cachedInnerUsage; //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
mutable int64_t lastRollingFeeUpdate;
mutable bool blockSinceLastRollingFeeBump;
mutable double rollingMinimumFeeRate; //!< minimum fee to get into the pool, decreases exponentially
void trackPackageRemoved(const CFeeRate& rate);
static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12; // public only for testing
typedef boost::multi_index_container<
// sorted by txid
boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>,
// sorted by fee rate
// sorted by entry time
// sorted by fee rate with ancestors
> indexed_transaction_set;
mutable CCriticalSection cs;
indexed_transaction_set mapTx;
typedef indexed_transaction_set::nth_index<0>::type::iterator txiter;
std::vector<std::pair<uint256, txiter> > vTxHashes; //!< All tx witness hashes/entries in mapTx, in random order
struct CompareIteratorByHash {
bool operator()(const txiter &a, const txiter &b) const {
return a->GetTx().GetHash() < b->GetTx().GetHash();
typedef std::set<txiter, CompareIteratorByHash> setEntries;
const setEntries & GetMemPoolParents(txiter entry) const;
const setEntries & GetMemPoolChildren(txiter entry) const;
typedef std::map<txiter, setEntries, CompareIteratorByHash> cacheMap;
struct TxLinks {
setEntries parents;
setEntries children;
typedef std::map<txiter, TxLinks, CompareIteratorByHash> txlinksMap;
txlinksMap mapLinks;
void UpdateParent(txiter entry, txiter parent, bool add);
void UpdateChild(txiter entry, txiter child, bool add);
std::vector<indexed_transaction_set::const_iterator> GetSortedDepthAndScore() const;
indirectmap<COutPoint, const CTransaction*> mapNextTx;
std::map<uint256, CAmount> mapDeltas;
/** Create a new CTxMemPool.
explicit CTxMemPool(CBlockPolicyEstimator* estimator = nullptr);
* If sanity-checking is turned on, check makes sure the pool is
* consistent (does not contain two transactions that spend the same inputs,
* all inputs are in the mapNextTx array). If sanity-checking is turned off,
* check does nothing.
void check(const CCoinsViewCache *pcoins) const;
void setSanityCheck(double dFrequency = 1.0) { nCheckFrequency = static_cast<uint32_t>(dFrequency * 4294967295.0); }
// addUnchecked must updated state for all ancestors of a given transaction,
// to track size/count of descendant transactions. First version of
// addUnchecked can be used to have it call CalculateMemPoolAncestors(), and
// then invoke the second version.
// Note that addUnchecked is ONLY called from ATMP outside of tests
// and any other callers may break wallet's in-mempool tracking (due to
// lack of CValidationInterface::TransactionAddedToMempool callbacks).
bool addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry, bool validFeeEstimate = true);
bool addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry, setEntries &setAncestors, bool validFeeEstimate = true);
void removeRecursive(const CTransaction &tx, MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN);
void removeForReorg(const CCoinsViewCache *pcoins, unsigned int nMemPoolHeight, int flags);
void removeConflicts(const CTransaction &tx);
void removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight);
void clear();
void _clear(); //lock free
bool CompareDepthAndScore(const uint256& hasha, const uint256& hashb);
void queryHashes(std::vector<uint256>& vtxid);
bool isSpent(const COutPoint& outpoint);
unsigned int GetTransactionsUpdated() const;
void AddTransactionsUpdated(unsigned int n);
* Check that none of this transactions inputs are in the mempool, and thus
* the tx is not dependent on other mempool transactions to be included in a block.
bool HasNoInputsOf(const CTransaction& tx) const;
/** Affect CreateNewBlock prioritisation of transactions */
void PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta);
void ApplyDelta(const uint256 hash, CAmount &nFeeDelta) const;
void ClearPrioritisation(const uint256 hash);
/** Remove a set of transactions from the mempool.
* If a transaction is in this set, then all in-mempool descendants must
* also be in the set, unless this transaction is being removed for being
* in a block.
* Set updateDescendants to true when removing a tx that was in a block, so
* that any in-mempool descendants have their ancestor state updated.
void RemoveStaged(setEntries &stage, bool updateDescendants, MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN);
/** When adding transactions from a disconnected block back to the mempool,
* new mempool entries may have children in the mempool (which is generally
* not the case when otherwise adding transactions).
* UpdateTransactionsFromBlock() will find child transactions and update the
* descendant state for each transaction in vHashesToUpdate (excluding any
* child transactions present in vHashesToUpdate, which are already accounted
* for). Note: vHashesToUpdate should be the set of transactions from the
* disconnected block that have been accepted back into the mempool.
void UpdateTransactionsFromBlock(const std::vector<uint256> &vHashesToUpdate);
/** Try to calculate all in-mempool ancestors of entry.
* (these are all calculated including the tx itself)
* limitAncestorCount = max number of ancestors
* limitAncestorSize = max size of ancestors
* limitDescendantCount = max number of descendants any ancestor can have
* limitDescendantSize = max size of descendants any ancestor can have
* errString = populated with error reason if any limits are hit
* fSearchForParents = whether to search a tx's vin for in-mempool parents, or
* look up parents from mapLinks. Must be true for entries not in the mempool
bool CalculateMemPoolAncestors(const CTxMemPoolEntry &entry, setEntries &setAncestors, uint64_t limitAncestorCount, uint64_t limitAncestorSize, uint64_t limitDescendantCount, uint64_t limitDescendantSize, std::string &errString, bool fSearchForParents = true) const;
/** Populate setDescendants with all in-mempool descendants of hash.
* Assumes that setDescendants includes all in-mempool descendants of anything
* already in it. */
void CalculateDescendants(txiter it, setEntries &setDescendants);
/** The minimum fee to get into the mempool, which may itself not be enough
* for larger-sized transactions.
* The incrementalRelayFee policy variable is used to bound the time it
* takes the fee rate to go back down all the way to 0. When the feerate
* would otherwise be half of this, it is set to 0 instead.
CFeeRate GetMinFee(size_t sizelimit) const;
/** Remove transactions from the mempool until its dynamic size is <= sizelimit.
* pvNoSpendsRemaining, if set, will be populated with the list of outpoints
* which are not in mempool which no longer have any spends in this mempool.
void TrimToSize(size_t sizelimit, std::vector<COutPoint>* pvNoSpendsRemaining=nullptr);
/** Expire all transaction (and their dependencies) in the mempool older than time. Return the number of removed transactions. */
int Expire(int64_t time);
/** Returns false if the transaction is in the mempool and not within the chain limit specified. */
bool TransactionWithinChainLimit(const uint256& txid, size_t chainLimit) const;
unsigned long size()
return mapTx.size();
uint64_t GetTotalTxSize() const
return totalTxSize;
bool exists(uint256 hash) const
return (mapTx.count(hash) != 0);
CTransactionRef get(const uint256& hash) const;
TxMempoolInfo info(const uint256& hash) const;
std::vector<TxMempoolInfo> infoAll() const;
size_t DynamicMemoryUsage() const;
boost::signals2::signal<void (CTransactionRef)> NotifyEntryAdded;
boost::signals2::signal<void (CTransactionRef, MemPoolRemovalReason)> NotifyEntryRemoved;
/** UpdateForDescendants is used by UpdateTransactionsFromBlock to update
* the descendants for a single transaction that has been added to the
* mempool but may have child transactions in the mempool, eg during a
* chain reorg. setExclude is the set of descendant transactions in the
* mempool that must not be accounted for (because any descendants in
* setExclude were added to the mempool after the transaction being
* updated and hence their state is already reflected in the parent
* state).
* cachedDescendants will be updated with the descendants of the transaction
* being updated, so that future invocations don't need to walk the
* same transaction again, if encountered in another transaction chain.
void UpdateForDescendants(txiter updateIt,
cacheMap &cachedDescendants,
const std::set<uint256> &setExclude);
/** Update ancestors of hash to add/remove it as a descendant transaction. */
void UpdateAncestorsOf(bool add, txiter hash, setEntries &setAncestors);
/** Set ancestor state for an entry */
void UpdateEntryForAncestors(txiter it, const setEntries &setAncestors);
/** For each transaction being removed, update ancestors and any direct children.
* If updateDescendants is true, then also update in-mempool descendants'
* ancestor state. */
void UpdateForRemoveFromMempool(const setEntries &entriesToRemove, bool updateDescendants);
/** Sever link between specified transaction and direct children. */
void UpdateChildrenForRemoval(txiter entry);
/** Before calling removeUnchecked for a given transaction,
* UpdateForRemoveFromMempool must be called on the entire (dependent) set
* of transactions being removed at the same time. We use each
* CTxMemPoolEntry's setMemPoolParents in order to walk ancestors of a
* given transaction that is removed, so we can't remove intermediate
* transactions in a chain before we've updated all the state for the
* removal.
void removeUnchecked(txiter entry, MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN);
* CCoinsView that brings transactions from a memorypool into view.
* It does not check for spendings by memory pool transactions.
* Instead, it provides access to all Coins which are either unspent in the
* base CCoinsView, or are outputs from any mempool transaction!
* This allows transaction replacement to work as expected, as you want to
* have all inputs "available" to check signatures, and any cycles in the
* dependency graph are checked directly in AcceptToMemoryPool.
* It also allows you to sign a double-spend directly in signrawtransaction,
* as long as the conflicting transaction is not yet confirmed.
class CCoinsViewMemPool : public CCoinsViewBacked
const CTxMemPool& mempool;
CCoinsViewMemPool(CCoinsView* baseIn, const CTxMemPool& mempoolIn);
bool GetCoin(const COutPoint &outpoint, Coin &coin) const override;
* DisconnectedBlockTransactions
* During the reorg, it's desirable to re-add previously confirmed transactions
* to the mempool, so that anything not re-confirmed in the new chain is
* available to be mined. However, it's more efficient to wait until the reorg
* is complete and process all still-unconfirmed transactions at that time,
* since we expect most confirmed transactions to (typically) still be
* confirmed in the new chain, and re-accepting to the memory pool is expensive
* (and therefore better to not do in the middle of reorg-processing).
* Instead, store the disconnected transactions (in order!) as we go, remove any
* that are included in blocks in the new chain, and then process the remaining
* still-unconfirmed transactions at the end.
// multi_index tag names
struct txid_index {};
struct insertion_order {};
struct DisconnectedBlockTransactions {
typedef boost::multi_index_container<
// sorted by txid
// sorted by order in the blockchain
> indexed_disconnected_transactions;
// It's almost certainly a logic bug if we don't clear out queuedTx before
// destruction, as we add to it while disconnecting blocks, and then we
// need to re-process remaining transactions to ensure mempool consistency.
// For now, assert() that we've emptied out this object on destruction.
// This assert() can always be removed if the reorg-processing code were
// to be refactored such that this assumption is no longer true (for
// instance if there was some other way we cleaned up the mempool after a
// reorg, besides draining this object).
~DisconnectedBlockTransactions() { assert(queuedTx.empty()); }
indexed_disconnected_transactions queuedTx;
uint64_t cachedInnerUsage = 0;
// Estimate the overhead of queuedTx to be 6 pointers + an allocation, as
// no exact formula for boost::multi_index_contained is implemented.
size_t DynamicMemoryUsage() const {
return memusage::MallocUsage(sizeof(CTransactionRef) + 6 * sizeof(void*)) * queuedTx.size() + cachedInnerUsage;
void addTransaction(const CTransactionRef& tx)
cachedInnerUsage += RecursiveDynamicUsage(tx);
// Remove entries based on txid_index, and update memory usage.
void removeForBlock(const std::vector<CTransactionRef>& vtx)
// Short-circuit in the common case of a block being added to the tip
if (queuedTx.empty()) {
for (auto const &tx : vtx) {
auto it = queuedTx.find(tx->GetHash());
if (it != queuedTx.end()) {
cachedInnerUsage -= RecursiveDynamicUsage(*it);
// Remove an entry by insertion_order index, and update memory usage.
void removeEntry(indexed_disconnected_transactions::index<insertion_order>::type::iterator entry)
cachedInnerUsage -= RecursiveDynamicUsage(*entry);
void clear()
cachedInnerUsage = 0;