lbrycrd/src/txmempool.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
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// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_TXMEMPOOL_H
#define BITCOIN_TXMEMPOOL_H
#include <memory>
#include <set>
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#include <map>
#include <vector>
#include <utility>
#include <string>
#include <amount.h>
#include <coins.h>
#include <crypto/siphash.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;
extern CCriticalSection cs_main;
/** 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
*
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* 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
{
private:
const CTransactionRef tx;
const CAmount nFee; //!< Cached to avoid expensive parent-transaction lookups
const size_t nTxWeight; //!< ... and avoid recomputing tx weight (also used for GetTxSize())
const size_t nUsageSize; //!< ... and total memory usage
const int64_t nTime; //!< Local time when entering the mempool
const unsigned int entryHeight; //!< Chain height when entering the mempool
const bool spendsCoinbase; //!< keep track of transactions that spend a coinbase
const int64_t sigOpCost; //!< Total sigop cost
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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.
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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;
public:
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;
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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); }
private:
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); }
private:
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); }
private:
int64_t feeDelta;
};
struct update_lock_points
{
explicit update_lock_points(const LockPoints& _lp) : lp(_lp) { }
void operator() (CTxMemPoolEntry &e) { e.UpdateLockPoints(lp); }
private:
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
{
public:
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 feerate of entry (fee/size) in descending order
* This is only used for transaction relay, so we use GetFee()
* instead of GetModifiedFee() to avoid leaking prioritization
* information via the sort order.
*/
class CompareTxMemPoolEntryByScore
{
public:
bool operator()(const CTxMemPoolEntry& a, const CTxMemPoolEntry& b) const
{
double f1 = (double)a.GetFee() * b.GetTxSize();
double f2 = (double)b.GetFee() * a.GetTxSize();
if (f1 == f2) {
return b.GetTx().GetHash() < a.GetTx().GetHash();
}
return f1 > f2;
}
};
class CompareTxMemPoolEntryByEntryTime
{
public:
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).
*/
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class CompareTxMemPoolEntryByAncestorFee
{
public:
template<typename T>
bool operator()(const T& a, const T& b) const
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{
double a_mod_fee, a_size, b_mod_fee, b_size;
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GetModFeeAndSize(a, a_mod_fee, a_size);
GetModFeeAndSize(b, b_mod_fee, b_size);
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// 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;
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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();
}
}
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};
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// Multi_index tag names
struct descendant_score {};
struct entry_time {};
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struct ancestor_score {};
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class CBlockPolicyEstimator;
estimatefee / estimatepriority RPC methods New RPC methods: return an estimate of the fee (or priority) a transaction needs to be likely to confirm in a given number of blocks. Mike Hearn created the first version of this method for estimating fees. It works as follows: For transactions that took 1 to N (I picked N=25) blocks to confirm, keep N buckets with at most 100 entries in each recording the fees-per-kilobyte paid by those transactions. (separate buckets are kept for transactions that confirmed because they are high-priority) The buckets are filled as blocks are found, and are saved/restored in a new fee_estiamtes.dat file in the data directory. A few variations on Mike's initial scheme: To estimate the fee needed for a transaction to confirm in X buckets, all of the samples in all of the buckets are used and a median of all of the data is used to make the estimate. For example, imagine 25 buckets each containing the full 100 entries. Those 2,500 samples are sorted, and the estimate of the fee needed to confirm in the very next block is the 50'th-highest-fee-entry in that sorted list; the estimate of the fee needed to confirm in the next two blocks is the 150'th-highest-fee-entry, etc. That algorithm has the nice property that estimates of how much fee you need to pay to get confirmed in block N will always be greater than or equal to the estimate for block N+1. It would clearly be wrong to say "pay 11 uBTC and you'll get confirmed in 3 blocks, but pay 12 uBTC and it will take LONGER". A single block will not contribute more than 10 entries to any one bucket, so a single miner and a large block cannot overwhelm the estimates.
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/**
* 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;
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/** 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 {
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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
{
private:
/** Salt */
const uint64_t k0, k1;
public:
SaltedTxidHasher();
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:
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* - 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
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* - descendant feerate [we use max(feerate of tx, feerate of tx with all descendants)]
* - time in mempool
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* - ancestor feerate [we use min(feerate of tx, feerate of tx with all unconfirmed ancestors)]
*
* 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
{
private:
uint32_t nCheckFrequency GUARDED_BY(cs); //!< 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.
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uint64_t cachedInnerUsage; //!< sum of dynamic memory usage of all the map elements (NOT the maps themselves)
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mutable int64_t lastRollingFeeUpdate;
mutable bool blockSinceLastRollingFeeBump;
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mutable double rollingMinimumFeeRate; //!< minimum fee to get into the pool, decreases exponentially
void trackPackageRemoved(const CFeeRate& rate) EXCLUSIVE_LOCKS_REQUIRED(cs);
public:
static const int ROLLING_FEE_HALFLIFE = 60 * 60 * 12; // public only for testing
typedef boost::multi_index_container<
CTxMemPoolEntry,
boost::multi_index::indexed_by<
// sorted by txid
boost::multi_index::hashed_unique<mempoolentry_txid, SaltedTxidHasher>,
// sorted by fee rate
boost::multi_index::ordered_non_unique<
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boost::multi_index::tag<descendant_score>,
boost::multi_index::identity<CTxMemPoolEntry>,
CompareTxMemPoolEntryByDescendantScore
>,
// sorted by entry time
boost::multi_index::ordered_non_unique<
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boost::multi_index::tag<entry_time>,
boost::multi_index::identity<CTxMemPoolEntry>,
CompareTxMemPoolEntryByEntryTime
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>,
// sorted by fee rate with ancestors
boost::multi_index::ordered_non_unique<
boost::multi_index::tag<ancestor_score>,
boost::multi_index::identity<CTxMemPoolEntry>,
CompareTxMemPoolEntryByAncestorFee
>
>
> indexed_transaction_set;
/**
* This mutex needs to be locked when accessing `mapTx` or other members
* that are guarded by it.
*
* @par Consistency guarantees
*
* By design, it is guaranteed that:
*
* 1. Locking both `cs_main` and `mempool.cs` will give a view of mempool
* that is consistent with current chain tip (`chainActive` and
* `pcoinsTip`) and is fully populated. Fully populated means that if the
* current active chain is missing transactions that were present in a
* previously active chain, all the missing transactions will have been
* re-added to the mempool and should be present if they meet size and
* consistency constraints.
*
* 2. Locking `mempool.cs` without `cs_main` will give a view of a mempool
* consistent with some chain that was active since `cs_main` was last
* locked, and that is fully populated as described above. It is ok for
* code that only needs to query or remove transactions from the mempool
* to lock just `mempool.cs` without `cs_main`.
*
* To provide these guarantees, it is necessary to lock both `cs_main` and
* `mempool.cs` whenever adding transactions to the mempool and whenever
* changing the chain tip. It's necessary to keep both mutexes locked until
* the mempool is consistent with the new chain tip and fully populated.
*
* @par Consistency bug
*
* The second guarantee above is not currently enforced, but
* https://github.com/bitcoin/bitcoin/pull/14193 will fix it. No known code
* in bitcoin currently depends on second guarantee, but it is important to
* fix for third party code that needs be able to frequently poll the
* mempool without locking `cs_main` and without encountering missing
* transactions during reorgs.
*/
mutable RecursiveMutex cs;
indexed_transaction_set mapTx GUARDED_BY(cs);
using txiter = indexed_transaction_set::nth_index<0>::type::const_iterator;
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 EXCLUSIVE_LOCKS_REQUIRED(cs);
const setEntries & GetMemPoolChildren(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
uint64_t CalculateDescendantMaximum(txiter entry) const EXCLUSIVE_LOCKS_REQUIRED(cs);
private:
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 EXCLUSIVE_LOCKS_REQUIRED(cs);
public:
indirectmap<COutPoint, const CTransaction*> mapNextTx GUARDED_BY(cs);
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) { LOCK(cs); 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).
void addUnchecked(const CTxMemPoolEntry& entry, bool validFeeEstimate = true) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
void addUnchecked(const CTxMemPoolEntry& entry, setEntries& setAncestors, bool validFeeEstimate = true) EXCLUSIVE_LOCKS_REQUIRED(cs, cs_main);
void removeRecursive(const CTransaction &tx, MemPoolRemovalReason reason = MemPoolRemovalReason::UNKNOWN);
void removeForReorg(const CCoinsViewCache *pcoins, unsigned int nMemPoolHeight, int flags) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
void removeConflicts(const CTransaction &tx) EXCLUSIVE_LOCKS_REQUIRED(cs);
void removeForBlock(const std::vector<CTransactionRef>& vtx, unsigned int nBlockHeight);
void clear();
void _clear() EXCLUSIVE_LOCKS_REQUIRED(cs); //lock free
bool CompareDepthAndScore(const uint256& hasha, const uint256& hashb);
void queryHashes(std::vector<uint256>& vtxid);
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bool isSpent(const COutPoint& outpoint) const;
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);
/** Get the transaction in the pool that spends the same prevout */
const CTransaction* GetConflictTx(const COutPoint& prevout) const EXCLUSIVE_LOCKS_REQUIRED(cs);
/** Returns an iterator to the given hash, if found */
boost::optional<txiter> GetIter(const uint256& txid) const EXCLUSIVE_LOCKS_REQUIRED(cs);
/** Translate a set of hashes into a set of pool iterators to avoid repeated lookups */
setEntries GetIterSet(const std::set<uint256>& hashes) const EXCLUSIVE_LOCKS_REQUIRED(cs);
/** 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) EXCLUSIVE_LOCKS_REQUIRED(cs);
/** 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) EXCLUSIVE_LOCKS_REQUIRED(cs_main);
/** 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 EXCLUSIVE_LOCKS_REQUIRED(cs);
/** 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) const EXCLUSIVE_LOCKS_REQUIRED(cs);
/** The minimum fee to get into the mempool, which may itself not be enough
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* for larger-sized transactions.
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* The incrementalRelayFee policy variable is used to bound the time it
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* 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);
/**
* Calculate the ancestor and descendant count for the given transaction.
* The counts include the transaction itself.
*/
void GetTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants) const;
unsigned long size() const
{
LOCK(cs);
return mapTx.size();
}
uint64_t GetTotalTxSize() const
{
LOCK(cs);
return totalTxSize;
}
bool exists(const uint256& hash) const
{
LOCK(cs);
return (mapTx.count(hash) != 0);
}
CTransactionRef get(const uint256& hash) const;
TxMempoolInfo info(const uint256& hash) const;
std::vector<TxMempoolInfo> infoAll() const;
estimatefee / estimatepriority RPC methods New RPC methods: return an estimate of the fee (or priority) a transaction needs to be likely to confirm in a given number of blocks. Mike Hearn created the first version of this method for estimating fees. It works as follows: For transactions that took 1 to N (I picked N=25) blocks to confirm, keep N buckets with at most 100 entries in each recording the fees-per-kilobyte paid by those transactions. (separate buckets are kept for transactions that confirmed because they are high-priority) The buckets are filled as blocks are found, and are saved/restored in a new fee_estiamtes.dat file in the data directory. A few variations on Mike's initial scheme: To estimate the fee needed for a transaction to confirm in X buckets, all of the samples in all of the buckets are used and a median of all of the data is used to make the estimate. For example, imagine 25 buckets each containing the full 100 entries. Those 2,500 samples are sorted, and the estimate of the fee needed to confirm in the very next block is the 50'th-highest-fee-entry in that sorted list; the estimate of the fee needed to confirm in the next two blocks is the 150'th-highest-fee-entry, etc. That algorithm has the nice property that estimates of how much fee you need to pay to get confirmed in block N will always be greater than or equal to the estimate for block N+1. It would clearly be wrong to say "pay 11 uBTC and you'll get confirmed in 3 blocks, but pay 12 uBTC and it will take LONGER". A single block will not contribute more than 10 entries to any one bucket, so a single miner and a large block cannot overwhelm the estimates.
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size_t DynamicMemoryUsage() const;
boost::signals2::signal<void (CTransactionRef)> NotifyEntryAdded;
boost::signals2::signal<void (CTransactionRef, MemPoolRemovalReason)> NotifyEntryRemoved;
private:
/** 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) EXCLUSIVE_LOCKS_REQUIRED(cs);
/** Update ancestors of hash to add/remove it as a descendant transaction. */
void UpdateAncestorsOf(bool add, txiter hash, setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs);
/** Set ancestor state for an entry */
void UpdateEntryForAncestors(txiter it, const setEntries &setAncestors) EXCLUSIVE_LOCKS_REQUIRED(cs);
/** 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) EXCLUSIVE_LOCKS_REQUIRED(cs);
/** Sever link between specified transaction and direct children. */
void UpdateChildrenForRemoval(txiter entry) EXCLUSIVE_LOCKS_REQUIRED(cs);
/** 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) EXCLUSIVE_LOCKS_REQUIRED(cs);
};
/**
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* CCoinsView that brings transactions from a mempool 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
{
protected:
const CTxMemPool& mempool;
public:
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<
CTransactionRef,
boost::multi_index::indexed_by<
// sorted by txid
boost::multi_index::hashed_unique<
boost::multi_index::tag<txid_index>,
mempoolentry_txid,
SaltedTxidHasher
>,
// sorted by order in the blockchain
boost::multi_index::sequenced<
boost::multi_index::tag<insertion_order>
>
>
> 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)
{
queuedTx.insert(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()) {
return;
}
for (auto const &tx : vtx) {
auto it = queuedTx.find(tx->GetHash());
if (it != queuedTx.end()) {
cachedInnerUsage -= RecursiveDynamicUsage(*it);
queuedTx.erase(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);
queuedTx.get<insertion_order>().erase(entry);
}
void clear()
{
cachedInnerUsage = 0;
queuedTx.clear();
}
};
#endif // BITCOIN_TXMEMPOOL_H