Merge #9602: Remove coin age priority and free transactions - implementation

b421e6d Update example bitcoin.conf (Alex Morcos)
7d4e950 Allow setting minrelaytxfee to 0 (Alex Morcos)
359e8a0 [cleanup] Remove coin age priority completely. (Alex Morcos)
f9b9371 [rpc] Remove priorityDelta from prioritisetransaction (Alex Morcos)
49be7e1 [rpc] Remove priority information from mempool RPC calls (Alex Morcos)
0315888 [test] Remove priority from tests (Alex Morcos)
f838005 No longer allow "free" transactions (Alex Morcos)
ad727f4 [rpc] sendrawtransaction no longer bypasses minRelayTxFee (Alex Morcos)
fe282ac [cleanup] Remove estimatePriority and estimateSmartPriority (Alex Morcos)
400b151 [debug] Change -printpriority option (Alex Morcos)
272b25a [mining] Remove -blockprioritysize. (Alex Morcos)
12839cd [rpc] Remove estimatepriority and estimatesmartpriority. (Alex Morcos)
ddf58c7 wallet: Remove sendfree (MarcoFalke)

Tree-SHA512: a9a4499405923ce794ef18f9e334dbbd59dfc73a3dc2df6f85cc9c62af6f353ec2eed9c2d5e58e904f918d0d7ab738f403dd4939d9bc2276136864fe63710782

30 files changed, 88 insertions, 592 deletions

diff --git a/src/bench/mempool_eviction.cpp b/src/bench/mempool_eviction.cpp
index 5790d51a82..31a392ae7c 100644
--- a/src/bench/mempool_eviction.cpp
+++ b/src/bench/mempool_eviction.cpp
@@ -12,14 +12,13 @@
 static void AddTx(const CTransaction& tx, const CAmount& nFee, CTxMemPool& pool)
 {
     int64_t nTime = 0;
-    double dPriority = 10.0;
     unsigned int nHeight = 1;
     bool spendsCoinbase = false;
     unsigned int sigOpCost = 4;
     LockPoints lp;
     pool.addUnchecked(tx.GetHash(), CTxMemPoolEntry(
-                                        MakeTransactionRef(tx), nFee, nTime, dPriority, nHeight,
-                                        tx.GetValueOut(), spendsCoinbase, sigOpCost, lp));
+                                        MakeTransactionRef(tx), nFee, nTime, nHeight,
+                                        spendsCoinbase, sigOpCost, lp));
 }
 
 // Right now this is only testing eviction performance in an extremely small
diff --git a/src/coins.cpp b/src/coins.cpp
index 4d0e4bc0ad..b2e33abf33 100644
--- a/src/coins.cpp
+++ b/src/coins.cpp
@@ -295,25 +295,6 @@ bool CCoinsViewCache::HaveInputs(const CTransaction& tx) const
     return true;
 }
 
-double CCoinsViewCache::GetPriority(const CTransaction &tx, int nHeight, CAmount &inChainInputValue) const
-{
-    inChainInputValue = 0;
-    if (tx.IsCoinBase())
-        return 0.0;
-    double dResult = 0.0;
-    BOOST_FOREACH(const CTxIn& txin, tx.vin)
-    {
-        const CCoins* coins = AccessCoins(txin.prevout.hash);
-        assert(coins);
-        if (!coins->IsAvailable(txin.prevout.n)) continue;
-        if (coins->nHeight <= nHeight) {
-            dResult += (double)(coins->vout[txin.prevout.n].nValue) * (nHeight-coins->nHeight);
-            inChainInputValue += coins->vout[txin.prevout.n].nValue;
-        }
-    }
-    return tx.ComputePriority(dResult);
-}
-
 CCoinsModifier::CCoinsModifier(CCoinsViewCache& cache_, CCoinsMap::iterator it_, size_t usage) : cache(cache_), it(it_), cachedCoinUsage(usage) {
     assert(!cache.hasModifier);
     cache.hasModifier = true;
diff --git a/src/coins.h b/src/coins.h
index 902cb57f69..d921f5c2a5 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -460,13 +460,6 @@ public:
     //! Check whether all prevouts of the transaction are present in the UTXO set represented by this view
     bool HaveInputs(const CTransaction& tx) const;
 
-    /**
-     * Return priority of tx at height nHeight. Also calculate the sum of the values of the inputs
-     * that are already in the chain.  These are the inputs that will age and increase priority as
-     * new blocks are added to the chain.
-     */
-    double GetPriority(const CTransaction &tx, int nHeight, CAmount &inChainInputValue) const;
-
     const CTxOut &GetOutputFor(const CTxIn& input) const;
 
     friend class CCoinsModifier;
diff --git a/src/init.cpp b/src/init.cpp
index 280793c72b..93131b4f94 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -444,8 +444,6 @@ std::string HelpMessage(HelpMessageMode mode)
     {
         strUsage += HelpMessageOpt("-logtimemicros", strprintf("Add microsecond precision to debug timestamps (default: %u)", DEFAULT_LOGTIMEMICROS));
         strUsage += HelpMessageOpt("-mocktime=<n>", "Replace actual time with <n> seconds since epoch (default: 0)");
-        strUsage += HelpMessageOpt("-limitfreerelay=<n>", strprintf("Continuously rate-limit free transactions to <n>*1000 bytes per minute (default: %u)", DEFAULT_LIMITFREERELAY));
-        strUsage += HelpMessageOpt("-relaypriority", strprintf("Require high priority for relaying free or low-fee transactions (default: %u)", DEFAULT_RELAYPRIORITY));
         strUsage += HelpMessageOpt("-maxsigcachesize=<n>", strprintf("Limit size of signature cache to <n> MiB (default: %u)", DEFAULT_MAX_SIG_CACHE_SIZE));
         strUsage += HelpMessageOpt("-maxtipage=<n>", strprintf("Maximum tip age in seconds to consider node in initial block download (default: %u)", DEFAULT_MAX_TIP_AGE));
     }
@@ -456,7 +454,7 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += HelpMessageOpt("-printtoconsole", _("Send trace/debug info to console instead of debug.log file"));
     if (showDebug)
     {
-        strUsage += HelpMessageOpt("-printpriority", strprintf("Log transaction priority and fee per kB when mining blocks (default: %u)", DEFAULT_PRINTPRIORITY));
+        strUsage += HelpMessageOpt("-printpriority", strprintf("Log transaction fee per kB when mining blocks (default: %u)", DEFAULT_PRINTPRIORITY));
     }
     strUsage += HelpMessageOpt("-shrinkdebugfile", _("Shrink debug.log file on client startup (default: 1 when no -debug)"));
 
@@ -476,7 +474,6 @@ std::string HelpMessage(HelpMessageMode mode)
     strUsage += HelpMessageGroup(_("Block creation options:"));
     strUsage += HelpMessageOpt("-blockmaxweight=<n>", strprintf(_("Set maximum BIP141 block weight (default: %d)"), DEFAULT_BLOCK_MAX_WEIGHT));
     strUsage += HelpMessageOpt("-blockmaxsize=<n>", strprintf(_("Set maximum block size in bytes (default: %d)"), DEFAULT_BLOCK_MAX_SIZE));
-    strUsage += HelpMessageOpt("-blockprioritysize=<n>", strprintf(_("Set maximum size of high-priority/low-fee transactions in bytes (default: %d)"), DEFAULT_BLOCK_PRIORITY_SIZE));
     strUsage += HelpMessageOpt("-blockmintxfee=<amt>", strprintf(_("Set lowest fee rate (in %s/kB) for transactions to be included in block creation. (default: %s)"), CURRENCY_UNIT, FormatMoney(DEFAULT_BLOCK_MIN_TX_FEE)));
     if (showDebug)
         strUsage += HelpMessageOpt("-blockversion=<n>", "Override block version to test forking scenarios");
@@ -998,17 +995,18 @@ bool AppInitParameterInteraction()
     if (nConnectTimeout <= 0)
         nConnectTimeout = DEFAULT_CONNECT_TIMEOUT;
 
-    // Fee-per-kilobyte amount considered the same as "free"
+    // Fee-per-kilobyte amount required for mempool acceptance and relay
     // If you are mining, be careful setting this:
     // if you set it to zero then
     // a transaction spammer can cheaply fill blocks using
-    // 1-satoshi-fee transactions. It should be set above the real
+    // 0-fee transactions. It should be set above the real
     // cost to you of processing a transaction.
     if (IsArgSet("-minrelaytxfee"))
     {
         CAmount n = 0;
-        if (!ParseMoney(GetArg("-minrelaytxfee", ""), n) || 0 == n)
+        if (!ParseMoney(GetArg("-minrelaytxfee", ""), n)) {
             return InitError(AmountErrMsg("minrelaytxfee", GetArg("-minrelaytxfee", "")));
+        }
         // High fee check is done afterward in CWallet::ParameterInteraction()
         ::minRelayTxFee = CFeeRate(n);
     } else if (incrementalRelayFee > ::minRelayTxFee) {
diff --git a/src/miner.cpp b/src/miner.cpp
index 167e74284c..67e7ff155b 100644
--- a/src/miner.cpp
+++ b/src/miner.cpp
@@ -39,8 +39,8 @@
 //
 // Unconfirmed transactions in the memory pool often depend on other
 // transactions in the memory pool. When we select transactions from the
-// pool, we select by highest priority or fee rate, so we might consider
-// transactions that depend on transactions that aren't yet in the block.
+// pool, we select by highest fee rate of a transaction combined with all
+// its ancestors.
 
 uint64_t nLastBlockTx = 0;
 uint64_t nLastBlockSize = 0;
@@ -135,9 +135,6 @@ void BlockAssembler::resetBlock()
     // These counters do not include coinbase tx
     nBlockTx = 0;
     nFees = 0;
-
-    lastFewTxs = 0;
-    blockFinished = false;
 }
 
 std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& scriptPubKeyIn)
@@ -180,7 +177,6 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
     // transaction (which in most cases can be a no-op).
     fIncludeWitness = IsWitnessEnabled(pindexPrev, chainparams.GetConsensus());
 
-    addPriorityTxs();
     addPackageTxs();
 
     nLastBlockTx = nBlockTx;
@@ -217,17 +213,6 @@ std::unique_ptr<CBlockTemplate> BlockAssembler::CreateNewBlock(const CScript& sc
     return std::move(pblocktemplate);
 }
 
-bool BlockAssembler::isStillDependent(CTxMemPool::txiter iter)
-{
-    BOOST_FOREACH(CTxMemPool::txiter parent, mempool.GetMemPoolParents(iter))
-    {
-        if (!inBlock.count(parent)) {
-            return true;
-        }
-    }
-    return false;
-}
-
 void BlockAssembler::onlyUnconfirmed(CTxMemPool::setEntries& testSet)
 {
     for (CTxMemPool::setEntries::iterator iit = testSet.begin(); iit != testSet.end(); ) {
@@ -275,58 +260,6 @@ bool BlockAssembler::TestPackageTransactions(const CTxMemPool::setEntries& packa
     return true;
 }
 
-bool BlockAssembler::TestForBlock(CTxMemPool::txiter iter)
-{
-    if (nBlockWeight + iter->GetTxWeight() >= nBlockMaxWeight) {
-        // If the block is so close to full that no more txs will fit
-        // or if we've tried more than 50 times to fill remaining space
-        // then flag that the block is finished
-        if (nBlockWeight >  nBlockMaxWeight - 400 || lastFewTxs > 50) {
-             blockFinished = true;
-             return false;
-        }
-        // Once we're within 4000 weight of a full block, only look at 50 more txs
-        // to try to fill the remaining space.
-        if (nBlockWeight > nBlockMaxWeight - 4000) {
-            lastFewTxs++;
-        }
-        return false;
-    }
-
-    if (fNeedSizeAccounting) {
-        if (nBlockSize + ::GetSerializeSize(iter->GetTx(), SER_NETWORK, PROTOCOL_VERSION) >= nBlockMaxSize) {
-            if (nBlockSize >  nBlockMaxSize - 100 || lastFewTxs > 50) {
-                 blockFinished = true;
-                 return false;
-            }
-            if (nBlockSize > nBlockMaxSize - 1000) {
-                lastFewTxs++;
-            }
-            return false;
-        }
-    }
-
-    if (nBlockSigOpsCost + iter->GetSigOpCost() >= MAX_BLOCK_SIGOPS_COST) {
-        // If the block has room for no more sig ops then
-        // flag that the block is finished
-        if (nBlockSigOpsCost > MAX_BLOCK_SIGOPS_COST - 8) {
-            blockFinished = true;
-            return false;
-        }
-        // Otherwise attempt to find another tx with fewer sigops
-        // to put in the block.
-        return false;
-    }
-
-    // Must check that lock times are still valid
-    // This can be removed once MTP is always enforced
-    // as long as reorgs keep the mempool consistent.
-    if (!IsFinalTx(iter->GetTx(), nHeight, nLockTimeCutoff))
-        return false;
-
-    return true;
-}
-
 void BlockAssembler::AddToBlock(CTxMemPool::txiter iter)
 {
     pblock->vtx.emplace_back(iter->GetSharedTx());
@@ -343,11 +276,7 @@ void BlockAssembler::AddToBlock(CTxMemPool::txiter iter)
 
     bool fPrintPriority = GetBoolArg("-printpriority", DEFAULT_PRINTPRIORITY);
     if (fPrintPriority) {
-        double dPriority = iter->GetPriority(nHeight);
-        CAmount dummy;
-        mempool.ApplyDeltas(iter->GetTx().GetHash(), dPriority, dummy);
-        LogPrintf("priority %.1f fee %s txid %s\n",
-                  dPriority,
+        LogPrintf("fee %s txid %s\n",
                   CFeeRate(iter->GetModifiedFee(), iter->GetTxSize()).ToString(),
                   iter->GetTx().GetHash().ToString());
     }
@@ -525,88 +454,6 @@ void BlockAssembler::addPackageTxs()
     }
 }
 
-void BlockAssembler::addPriorityTxs()
-{
-    // How much of the block should be dedicated to high-priority transactions,
-    // included regardless of the fees they pay
-    unsigned int nBlockPrioritySize = GetArg("-blockprioritysize", DEFAULT_BLOCK_PRIORITY_SIZE);
-    nBlockPrioritySize = std::min(nBlockMaxSize, nBlockPrioritySize);
-
-    if (nBlockPrioritySize == 0) {
-        return;
-    }
-
-    bool fSizeAccounting = fNeedSizeAccounting;
-    fNeedSizeAccounting = true;
-
-    // This vector will be sorted into a priority queue:
-    std::vector<TxCoinAgePriority> vecPriority;
-    TxCoinAgePriorityCompare pricomparer;
-    std::map<CTxMemPool::txiter, double, CTxMemPool::CompareIteratorByHash> waitPriMap;
-    typedef std::map<CTxMemPool::txiter, double, CTxMemPool::CompareIteratorByHash>::iterator waitPriIter;
-    double actualPriority = -1;
-
-    vecPriority.reserve(mempool.mapTx.size());
-    for (CTxMemPool::indexed_transaction_set::iterator mi = mempool.mapTx.begin();
-         mi != mempool.mapTx.end(); ++mi)
-    {
-        double dPriority = mi->GetPriority(nHeight);
-        CAmount dummy;
-        mempool.ApplyDeltas(mi->GetTx().GetHash(), dPriority, dummy);
-        vecPriority.push_back(TxCoinAgePriority(dPriority, mi));
-    }
-    std::make_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
-
-    CTxMemPool::txiter iter;
-    while (!vecPriority.empty() && !blockFinished) { // add a tx from priority queue to fill the blockprioritysize
-        iter = vecPriority.front().second;
-        actualPriority = vecPriority.front().first;
-        std::pop_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
-        vecPriority.pop_back();
-
-        // If tx already in block, skip
-        if (inBlock.count(iter)) {
-            assert(false); // shouldn't happen for priority txs
-            continue;
-        }
-
-        // cannot accept witness transactions into a non-witness block
-        if (!fIncludeWitness && iter->GetTx().HasWitness())
-            continue;
-
-        // If tx is dependent on other mempool txs which haven't yet been included
-        // then put it in the waitSet
-        if (isStillDependent(iter)) {
-            waitPriMap.insert(std::make_pair(iter, actualPriority));
-            continue;
-        }
-
-        // If this tx fits in the block add it, otherwise keep looping
-        if (TestForBlock(iter)) {
-            AddToBlock(iter);
-
-            // If now that this txs is added we've surpassed our desired priority size
-            // or have dropped below the AllowFreeThreshold, then we're done adding priority txs
-            if (nBlockSize >= nBlockPrioritySize || !AllowFree(actualPriority)) {
-                break;
-            }
-
-            // This tx was successfully added, so
-            // add transactions that depend on this one to the priority queue to try again
-            BOOST_FOREACH(CTxMemPool::txiter child, mempool.GetMemPoolChildren(iter))
-            {
-                waitPriIter wpiter = waitPriMap.find(child);
-                if (wpiter != waitPriMap.end()) {
-                    vecPriority.push_back(TxCoinAgePriority(wpiter->second,child));
-                    std::push_heap(vecPriority.begin(), vecPriority.end(), pricomparer);
-                    waitPriMap.erase(wpiter);
-                }
-            }
-        }
-    }
-    fNeedSizeAccounting = fSizeAccounting;
-}
-
 void IncrementExtraNonce(CBlock* pblock, const CBlockIndex* pindexPrev, unsigned int& nExtraNonce)
 {
     // Update nExtraNonce
diff --git a/src/miner.h b/src/miner.h
index fc2526ff5a..c105d07c23 100644
--- a/src/miner.h
+++ b/src/miner.h
@@ -158,10 +158,6 @@ private:
     int64_t nLockTimeCutoff;
     const CChainParams& chainparams;
 
-    // Variables used for addPriorityTxs
-    int lastFewTxs;
-    bool blockFinished;
-
 public:
     struct Options {
         Options();
@@ -184,17 +180,9 @@ private:
     void AddToBlock(CTxMemPool::txiter iter);
 
     // Methods for how to add transactions to a block.
-    /** Add transactions based on tx "priority" */
-    void addPriorityTxs();
     /** Add transactions based on feerate including unconfirmed ancestors */
     void addPackageTxs();
 
-    // helper function for addPriorityTxs
-    /** Test if tx will still "fit" in the block */
-    bool TestForBlock(CTxMemPool::txiter iter);
-    /** Test if tx still has unconfirmed parents not yet in block */
-    bool isStillDependent(CTxMemPool::txiter iter);
-
     // helper functions for addPackageTxs()
     /** Remove confirmed (inBlock) entries from given set */
     void onlyUnconfirmed(CTxMemPool::setEntries& testSet);
diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 3ec1a1c27d..71a0a1de22 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -1853,7 +1853,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
                             LogPrint("mempool", "   invalid orphan tx %s\n", orphanHash.ToString());
                         }
                         // Has inputs but not accepted to mempool
-                        // Probably non-standard or insufficient fee/priority
+                        // Probably non-standard or insufficient fee
                         LogPrint("mempool", "   removed orphan tx %s\n", orphanHash.ToString());
                         vEraseQueue.push_back(orphanHash);
                         if (!orphanTx.HasWitness() && !stateDummy.CorruptionPossible()) {
@@ -3249,9 +3249,8 @@ bool SendMessages(CNode* pto, CConnman& connman, const std::atomic<bool>& interr
                 static CFeeRate default_feerate(DEFAULT_MIN_RELAY_TX_FEE);
                 static FeeFilterRounder filterRounder(default_feerate);
                 CAmount filterToSend = filterRounder.round(currentFilter);
-                // If we don't allow free transactions, then we always have a fee filter of at least minRelayTxFee
-                if (GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY) <= 0)
-                    filterToSend = std::max(filterToSend, ::minRelayTxFee.GetFeePerK());
+                // We always have a fee filter of at least minRelayTxFee
+                filterToSend = std::max(filterToSend, ::minRelayTxFee.GetFeePerK());
                 if (filterToSend != pto->lastSentFeeFilter) {
                     connman.PushMessage(pto, msgMaker.Make(NetMsgType::FEEFILTER, filterToSend));
                     pto->lastSentFeeFilter = filterToSend;
diff --git a/src/policy/fees.cpp b/src/policy/fees.cpp
index 8f6a1e60f4..89220f26b6 100644
--- a/src/policy/fees.cpp
+++ b/src/policy/fees.cpp
@@ -452,24 +452,6 @@ CFeeRate CBlockPolicyEstimator::estimateSmartFee(int confTarget, int *answerFoun
     return CFeeRate(median);
 }
 
-double CBlockPolicyEstimator::estimatePriority(int confTarget)
-{
-    return -1;
-}
-
-double CBlockPolicyEstimator::estimateSmartPriority(int confTarget, int *answerFoundAtTarget, const CTxMemPool& pool)
-{
-    if (answerFoundAtTarget)
-        *answerFoundAtTarget = confTarget;
-
-    // If mempool is limiting txs, no priority txs are allowed
-    CAmount minPoolFee = pool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFeePerK();
-    if (minPoolFee > 0)
-        return INF_PRIORITY;
-
-    return -1;
-}
-
 void CBlockPolicyEstimator::Write(CAutoFile& fileout)
 {
     fileout << nBestSeenHeight;
diff --git a/src/policy/fees.h b/src/policy/fees.h
index 064466afe4..f2f430861c 100644
--- a/src/policy/fees.h
+++ b/src/policy/fees.h
@@ -182,7 +182,6 @@ static const double SUFFICIENT_FEETXS = 1;
 static constexpr double MIN_FEERATE = 10;
 static const double MAX_FEERATE = 1e7;
 static const double INF_FEERATE = MAX_MONEY;
-static const double INF_PRIORITY = 1e9 * MAX_MONEY;
 
 // We have to lump transactions into buckets based on feerate, but we want to be able
 // to give accurate estimates over a large range of potential feerates
@@ -223,20 +222,6 @@ public:
      */
     CFeeRate estimateSmartFee(int confTarget, int *answerFoundAtTarget, const CTxMemPool& pool);
 
-    /** Return a priority estimate.
-     *  DEPRECATED
-     *  Returns -1
-     */
-    double estimatePriority(int confTarget);
-
-    /** Estimate priority needed to get be included in a block within
-     *  confTarget blocks.
-     *  DEPRECATED
-     *  Returns -1 unless mempool is currently limited then returns INF_PRIORITY
-     *  answerFoundAtTarget is set to confTarget
-     */
-    double estimateSmartPriority(int confTarget, int *answerFoundAtTarget, const CTxMemPool& pool);
-
     /** Write estimation data to a file */
     void Write(CAutoFile& fileout);
 
diff --git a/src/policy/policy.h b/src/policy/policy.h
index 9b1323ac26..6df541bc0f 100644
--- a/src/policy/policy.h
+++ b/src/policy/policy.h
@@ -16,8 +16,6 @@ class CCoinsViewCache;
 
 /** Default for -blockmaxsize, which controls the maximum size of block the mining code will create **/
 static const unsigned int DEFAULT_BLOCK_MAX_SIZE = 750000;
-/** Default for -blockprioritysize, maximum space for zero/low-fee transactions **/
-static const unsigned int DEFAULT_BLOCK_PRIORITY_SIZE = 0;
 /** Default for -blockmaxweight, which controls the range of block weights the mining code will create **/
 static const unsigned int DEFAULT_BLOCK_MAX_WEIGHT = 3000000;
 /** Default for -blockmintxfee, which sets the minimum feerate for a transaction in blocks created by mining code **/
diff --git a/src/primitives/transaction.cpp b/src/primitives/transaction.cpp
index 28ef1fb464..a0d7793f97 100644
--- a/src/primitives/transaction.cpp
+++ b/src/primitives/transaction.cpp
@@ -92,32 +92,6 @@ CAmount CTransaction::GetValueOut() const
     return nValueOut;
 }
 
-double CTransaction::ComputePriority(double dPriorityInputs, unsigned int nTxSize) const
-{
-    nTxSize = CalculateModifiedSize(nTxSize);
-    if (nTxSize == 0) return 0.0;
-
-    return dPriorityInputs / nTxSize;
-}
-
-unsigned int CTransaction::CalculateModifiedSize(unsigned int nTxSize) const
-{
-    // In order to avoid disincentivizing cleaning up the UTXO set we don't count
-    // the constant overhead for each txin and up to 110 bytes of scriptSig (which
-    // is enough to cover a compressed pubkey p2sh redemption) for priority.
-    // Providing any more cleanup incentive than making additional inputs free would
-    // risk encouraging people to create junk outputs to redeem later.
-    if (nTxSize == 0)
-        nTxSize = (GetTransactionWeight(*this) + WITNESS_SCALE_FACTOR - 1) / WITNESS_SCALE_FACTOR;
-    for (std::vector<CTxIn>::const_iterator it(vin.begin()); it != vin.end(); ++it)
-    {
-        unsigned int offset = 41U + std::min(110U, (unsigned int)it->scriptSig.size());
-        if (nTxSize > offset)
-            nTxSize -= offset;
-    }
-    return nTxSize;
-}
-
 unsigned int CTransaction::GetTotalSize() const
 {
     return ::GetSerializeSize(*this, SER_NETWORK, PROTOCOL_VERSION);
diff --git a/src/primitives/transaction.h b/src/primitives/transaction.h
index af2986a41b..d413e8b087 100644
--- a/src/primitives/transaction.h
+++ b/src/primitives/transaction.h
@@ -361,12 +361,6 @@ public:
     // GetValueIn() is a method on CCoinsViewCache, because
     // inputs must be known to compute value in.
 
-    // Compute priority, given priority of inputs and (optionally) tx size
-    double ComputePriority(double dPriorityInputs, unsigned int nTxSize=0) const;
-
-    // Compute modified tx size for priority calculation (optionally given tx size)
-    unsigned int CalculateModifiedSize(unsigned int nTxSize=0) const;
-
     /**
      * Get the total transaction size in bytes, including witness data.
      * "Total Size" defined in BIP141 and BIP144.
diff --git a/src/qt/coincontroldialog.cpp b/src/qt/coincontroldialog.cpp
index d4fd8bd372..1d19c65753 100644
--- a/src/qt/coincontroldialog.cpp
+++ b/src/qt/coincontroldialog.cpp
@@ -444,11 +444,7 @@ void CoinControlDialog::updateLabels(WalletModel *model, QDialog* dialog)
     CAmount nChange             = 0;
     unsigned int nBytes         = 0;
     unsigned int nBytesInputs   = 0;
-    double dPriority            = 0;
-    double dPriorityInputs      = 0;
     unsigned int nQuantity      = 0;
-    int nQuantityUncompressed   = 0;
-    bool fAllowFree             = false;
     bool fWitness               = false;
 
     std::vector<COutPoint> vCoinControl;
@@ -473,9 +469,6 @@ void CoinControlDialog::updateLabels(WalletModel *model, QDialog* dialog)
         // Amount
         nAmount += out.tx->tx->vout[out.i].nValue;
 
-        // Priority
-        dPriorityInputs += (double)out.tx->tx->vout[out.i].nValue * (out.nDepth+1);
-
         // Bytes
         CTxDestination address;
         int witnessversion = 0;
@@ -492,8 +485,6 @@ void CoinControlDialog::updateLabels(WalletModel *model, QDialog* dialog)
             if (keyid && model->getPubKey(*keyid, pubkey))
             {
                 nBytesInputs += (pubkey.IsCompressed() ? 148 : 180);
-                if (!pubkey.IsCompressed())
-                    nQuantityUncompressed++;
             }
             else
                 nBytesInputs += 148; // in all error cases, simply assume 148 here
@@ -525,17 +516,6 @@ void CoinControlDialog::updateLabels(WalletModel *model, QDialog* dialog)
         if (nPayFee > 0 && coinControl->nMinimumTotalFee > nPayFee)
             nPayFee = coinControl->nMinimumTotalFee;
 
-
-        // Allow free? (require at least hard-coded threshold and default to that if no estimate)
-        double mempoolEstimatePriority = mempool.estimateSmartPriority(nTxConfirmTarget);
-        dPriority = dPriorityInputs / (nBytes - nBytesInputs + (nQuantityUncompressed * 29)); // 29 = 180 - 151 (uncompressed public keys are over the limit. max 151 bytes of the input are ignored for priority)
-        double dPriorityNeeded = std::max(mempoolEstimatePriority, AllowFreeThreshold());
-        fAllowFree = (dPriority >= dPriorityNeeded);
-
-        if (fSendFreeTransactions)
-            if (fAllowFree && nBytes <= MAX_FREE_TRANSACTION_CREATE_SIZE)
-                nPayFee = 0;
-
         if (nPayAmount > 0)
         {
             nChange = nAmount - nPayAmount;
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index dd46a3c3ba..24ced1a819 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -341,8 +341,6 @@ std::string EntryDescriptionString()
            "    \"modifiedfee\" : n,      (numeric) transaction fee with fee deltas used for mining priority\n"
            "    \"time\" : n,             (numeric) local time transaction entered pool in seconds since 1 Jan 1970 GMT\n"
            "    \"height\" : n,           (numeric) block height when transaction entered pool\n"
-           "    \"startingpriority\" : n, (numeric) DEPRECATED. Priority when transaction entered pool\n"
-           "    \"currentpriority\" : n,  (numeric) DEPRECATED. Transaction priority now\n"
            "    \"descendantcount\" : n,  (numeric) number of in-mempool descendant transactions (including this one)\n"
            "    \"descendantsize\" : n,   (numeric) virtual transaction size of in-mempool descendants (including this one)\n"
            "    \"descendantfees\" : n,   (numeric) modified fees (see above) of in-mempool descendants (including this one)\n"
@@ -363,8 +361,6 @@ void entryToJSON(UniValue &info, const CTxMemPoolEntry &e)
     info.push_back(Pair("modifiedfee", ValueFromAmount(e.GetModifiedFee())));
     info.push_back(Pair("time", e.GetTime()));
     info.push_back(Pair("height", (int)e.GetHeight()));
-    info.push_back(Pair("startingpriority", e.GetPriority(e.GetHeight())));
-    info.push_back(Pair("currentpriority", e.GetPriority(chainActive.Height())));
     info.push_back(Pair("descendantcount", e.GetCountWithDescendants()));
     info.push_back(Pair("descendantsize", e.GetSizeWithDescendants()));
     info.push_back(Pair("descendantfees", e.GetModFeesWithDescendants()));
diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index 29bdb37682..a8c5c21ef1 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -107,11 +107,8 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "keypoolrefill", 0, "newsize" },
     { "getrawmempool", 0, "verbose" },
     { "estimatefee", 0, "nblocks" },
-    { "estimatepriority", 0, "nblocks" },
     { "estimatesmartfee", 0, "nblocks" },
-    { "estimatesmartpriority", 0, "nblocks" },
-    { "prioritisetransaction", 1, "priority_delta" },
-    { "prioritisetransaction", 2, "fee_delta" },
+    { "prioritisetransaction", 1, "fee_delta" },
     { "setban", 2, "bantime" },
     { "setban", 3, "absolute" },
     { "setnetworkactive", 0, "state" },
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index 7708771d00..4ff8f39edc 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -258,31 +258,28 @@ UniValue getmininginfo(const JSONRPCRequest& request)
 // NOTE: Unlike wallet RPC (which use BTC values), mining RPCs follow GBT (BIP 22) in using satoshi amounts
 UniValue prioritisetransaction(const JSONRPCRequest& request)
 {
-    if (request.fHelp || request.params.size() != 3)
+    if (request.fHelp || request.params.size() != 2)
         throw runtime_error(
-            "prioritisetransaction <txid> <priority delta> <fee delta>\n"
+            "prioritisetransaction <txid> <fee delta>\n"
             "Accepts the transaction into mined blocks at a higher (or lower) priority\n"
             "\nArguments:\n"
             "1. \"txid\"       (string, required) The transaction id.\n"
-            "2. priority_delta (numeric, required) The priority to add or subtract.\n"
-            "                  The transaction selection algorithm considers the tx as it would have a higher priority.\n"
-            "                  (priority of a transaction is calculated: coinage * value_in_satoshis / txsize) \n"
-            "3. fee_delta      (numeric, required) The fee value (in satoshis) to add (or subtract, if negative).\n"
+            "2. fee_delta      (numeric, required) The fee value (in satoshis) to add (or subtract, if negative).\n"
             "                  The fee is not actually paid, only the algorithm for selecting transactions into a block\n"
             "                  considers the transaction as it would have paid a higher (or lower) fee.\n"
             "\nResult:\n"
             "true              (boolean) Returns true\n"
             "\nExamples:\n"
-            + HelpExampleCli("prioritisetransaction", "\"txid\" 0.0 10000")
-            + HelpExampleRpc("prioritisetransaction", "\"txid\", 0.0, 10000")
+            + HelpExampleCli("prioritisetransaction", "\"txid\" 10000")
+            + HelpExampleRpc("prioritisetransaction", "\"txid\", 10000")
         );
 
     LOCK(cs_main);
 
     uint256 hash = ParseHashStr(request.params[0].get_str(), "txid");
-    CAmount nAmount = request.params[2].get_int64();
+    CAmount nAmount = request.params[1].get_int64();
 
-    mempool.PrioritiseTransaction(hash, request.params[1].get_real(), nAmount);
+    mempool.PrioritiseTransaction(hash, nAmount);
     return true;
 }
 
@@ -811,33 +808,6 @@ UniValue estimatefee(const JSONRPCRequest& request)
     return ValueFromAmount(feeRate.GetFeePerK());
 }
 
-UniValue estimatepriority(const JSONRPCRequest& request)
-{
-    if (request.fHelp || request.params.size() != 1)
-        throw runtime_error(
-            "estimatepriority nblocks\n"
-            "\nDEPRECATED. Estimates the approximate priority a zero-fee transaction needs to begin\n"
-            "confirmation within nblocks blocks.\n"
-            "\nArguments:\n"
-            "1. nblocks     (numeric, required)\n"
-            "\nResult:\n"
-            "n              (numeric) estimated priority\n"
-            "\n"
-            "A negative value is returned if not enough transactions and blocks\n"
-            "have been observed to make an estimate.\n"
-            "\nExample:\n"
-            + HelpExampleCli("estimatepriority", "6")
-            );
-
-    RPCTypeCheck(request.params, boost::assign::list_of(UniValue::VNUM));
-
-    int nBlocks = request.params[0].get_int();
-    if (nBlocks < 1)
-        nBlocks = 1;
-
-    return mempool.estimatePriority(nBlocks);
-}
-
 UniValue estimatesmartfee(const JSONRPCRequest& request)
 {
     if (request.fHelp || request.params.size() != 1)
@@ -875,48 +845,12 @@ UniValue estimatesmartfee(const JSONRPCRequest& request)
     return result;
 }
 
-UniValue estimatesmartpriority(const JSONRPCRequest& request)
-{
-    if (request.fHelp || request.params.size() != 1)
-        throw runtime_error(
-            "estimatesmartpriority nblocks\n"
-            "\nDEPRECATED. WARNING: This interface is unstable and may disappear or change!\n"
-            "\nEstimates the approximate priority a zero-fee transaction needs to begin\n"
-            "confirmation within nblocks blocks if possible and return the number of blocks\n"
-            "for which the estimate is valid.\n"
-            "\nArguments:\n"
-            "1. nblocks     (numeric, required)\n"
-            "\nResult:\n"
-            "{\n"
-            "  \"priority\" : x.x,    (numeric) estimated priority\n"
-            "  \"blocks\" : n         (numeric) block number where estimate was found\n"
-            "}\n"
-            "\n"
-            "A negative value is returned if not enough transactions and blocks\n"
-            "have been observed to make an estimate for any number of blocks.\n"
-            "However if the mempool reject fee is set it will return 1e9 * MAX_MONEY.\n"
-            "\nExample:\n"
-            + HelpExampleCli("estimatesmartpriority", "6")
-            );
-
-    RPCTypeCheck(request.params, boost::assign::list_of(UniValue::VNUM));
-
-    int nBlocks = request.params[0].get_int();
-
-    UniValue result(UniValue::VOBJ);
-    int answerFound;
-    double priority = mempool.estimateSmartPriority(nBlocks, &answerFound);
-    result.push_back(Pair("priority", priority));
-    result.push_back(Pair("blocks", answerFound));
-    return result;
-}
-
 static const CRPCCommand commands[] =
 { //  category              name                      actor (function)         okSafeMode
   //  --------------------- ------------------------  -----------------------  ----------
     { "mining",             "getnetworkhashps",       &getnetworkhashps,       true,  {"nblocks","height"} },
     { "mining",             "getmininginfo",          &getmininginfo,          true,  {} },
-    { "mining",             "prioritisetransaction",  &prioritisetransaction,  true,  {"txid","priority_delta","fee_delta"} },
+    { "mining",             "prioritisetransaction",  &prioritisetransaction,  true,  {"txid","fee_delta"} },
     { "mining",             "getblocktemplate",       &getblocktemplate,       true,  {"template_request"} },
     { "mining",             "submitblock",            &submitblock,            true,  {"hexdata","parameters"} },
 
@@ -924,9 +858,7 @@ static const CRPCCommand commands[] =
     { "generating",         "generatetoaddress",      &generatetoaddress,      true,  {"nblocks","address","maxtries"} },
 
     { "util",               "estimatefee",            &estimatefee,            true,  {"nblocks"} },
-    { "util",               "estimatepriority",       &estimatepriority,       true,  {"nblocks"} },
     { "util",               "estimatesmartfee",       &estimatesmartfee,       true,  {"nblocks"} },
-    { "util",               "estimatesmartpriority",  &estimatesmartpriority,  true,  {"nblocks"} },
 };
 
 void RegisterMiningRPCCommands(CRPCTable &t)
diff --git a/src/rpc/misc.cpp b/src/rpc/misc.cpp
index 23515f116f..5d86e94846 100644
--- a/src/rpc/misc.cpp
+++ b/src/rpc/misc.cpp
@@ -62,7 +62,7 @@ UniValue getinfo(const JSONRPCRequest& request)
             "  \"keypoolsize\": xxxx,        (numeric) how many new keys are pre-generated\n"
             "  \"unlocked_until\": ttt,      (numeric) the timestamp in seconds since epoch (midnight Jan 1 1970 GMT) that the wallet is unlocked for transfers, or 0 if the wallet is locked\n"
             "  \"paytxfee\": x.xxxx,         (numeric) the transaction fee set in " + CURRENCY_UNIT + "/kB\n"
-            "  \"relayfee\": x.xxxx,         (numeric) minimum relay fee for non-free transactions in " + CURRENCY_UNIT + "/kB\n"
+            "  \"relayfee\": x.xxxx,         (numeric) minimum relay fee for transactions in " + CURRENCY_UNIT + "/kB\n"
             "  \"errors\": \"...\"           (string) any error messages\n"
             "}\n"
             "\nExamples:\n"
diff --git a/src/rpc/net.cpp b/src/rpc/net.cpp
index f590db5efa..a7169749c3 100644
--- a/src/rpc/net.cpp
+++ b/src/rpc/net.cpp
@@ -417,7 +417,7 @@ UniValue getnetworkinfo(const JSONRPCRequest& request)
             "  }\n"
             "  ,...\n"
             "  ],\n"
-            "  \"relayfee\": x.xxxxxxxx,                (numeric) minimum relay fee for non-free transactions in " + CURRENCY_UNIT + "/kB\n"
+            "  \"relayfee\": x.xxxxxxxx,                (numeric) minimum relay fee for transactions in " + CURRENCY_UNIT + "/kB\n"
             "  \"incrementalfee\": x.xxxxxxxx,          (numeric) minimum fee increment for mempool limiting or BIP 125 replacement in " + CURRENCY_UNIT + "/kB\n"
             "  \"localaddresses\": [                    (array) list of local addresses\n"
             "  {\n"
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 79b27d0475..e6fe67de92 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -897,7 +897,7 @@ UniValue sendrawtransaction(const JSONRPCRequest& request)
     CTransactionRef tx(MakeTransactionRef(std::move(mtx)));
     const uint256& hashTx = tx->GetHash();
 
-    bool fLimitFree = false;
+    bool fLimitFree = true;
     CAmount nMaxRawTxFee = maxTxFee;
     if (request.params.size() > 1 && request.params[1].get_bool())
         nMaxRawTxFee = 0;
diff --git a/src/test/mempool_tests.cpp b/src/test/mempool_tests.cpp
index 91f549fe48..a3f706d9af 100644
--- a/src/test/mempool_tests.cpp
+++ b/src/test/mempool_tests.cpp
@@ -126,28 +126,28 @@ BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
     tx1.vout.resize(1);
     tx1.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx1.vout[0].nValue = 10 * COIN;
-    pool.addUnchecked(tx1.GetHash(), entry.Fee(10000LL).Priority(10.0).FromTx(tx1));
+    pool.addUnchecked(tx1.GetHash(), entry.Fee(10000LL).FromTx(tx1));
 
     /* highest fee */
     CMutableTransaction tx2 = CMutableTransaction();
     tx2.vout.resize(1);
     tx2.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx2.vout[0].nValue = 2 * COIN;
-    pool.addUnchecked(tx2.GetHash(), entry.Fee(20000LL).Priority(9.0).FromTx(tx2));
+    pool.addUnchecked(tx2.GetHash(), entry.Fee(20000LL).FromTx(tx2));
 
     /* lowest fee */
     CMutableTransaction tx3 = CMutableTransaction();
     tx3.vout.resize(1);
     tx3.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx3.vout[0].nValue = 5 * COIN;
-    pool.addUnchecked(tx3.GetHash(), entry.Fee(0LL).Priority(100.0).FromTx(tx3));
+    pool.addUnchecked(tx3.GetHash(), entry.Fee(0LL).FromTx(tx3));
 
     /* 2nd highest fee */
     CMutableTransaction tx4 = CMutableTransaction();
     tx4.vout.resize(1);
     tx4.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx4.vout[0].nValue = 6 * COIN;
-    pool.addUnchecked(tx4.GetHash(), entry.Fee(15000LL).Priority(1.0).FromTx(tx4));
+    pool.addUnchecked(tx4.GetHash(), entry.Fee(15000LL).FromTx(tx4));
 
     /* equal fee rate to tx1, but newer */
     CMutableTransaction tx5 = CMutableTransaction();
@@ -155,7 +155,6 @@ BOOST_AUTO_TEST_CASE(MempoolIndexingTest)
     tx5.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx5.vout[0].nValue = 11 * COIN;
     entry.nTime = 1;
-    entry.dPriority = 10.0;
     pool.addUnchecked(tx5.GetHash(), entry.Fee(10000LL).FromTx(tx5));
     BOOST_CHECK_EQUAL(pool.size(), 5);
 
@@ -328,14 +327,14 @@ BOOST_AUTO_TEST_CASE(MempoolAncestorIndexingTest)
     tx1.vout.resize(1);
     tx1.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx1.vout[0].nValue = 10 * COIN;
-    pool.addUnchecked(tx1.GetHash(), entry.Fee(10000LL).Priority(10.0).FromTx(tx1));
+    pool.addUnchecked(tx1.GetHash(), entry.Fee(10000LL).FromTx(tx1));
 
     /* highest fee */
     CMutableTransaction tx2 = CMutableTransaction();
     tx2.vout.resize(1);
     tx2.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx2.vout[0].nValue = 2 * COIN;
-    pool.addUnchecked(tx2.GetHash(), entry.Fee(20000LL).Priority(9.0).FromTx(tx2));
+    pool.addUnchecked(tx2.GetHash(), entry.Fee(20000LL).FromTx(tx2));
     uint64_t tx2Size = GetVirtualTransactionSize(tx2);
 
     /* lowest fee */
@@ -343,14 +342,14 @@ BOOST_AUTO_TEST_CASE(MempoolAncestorIndexingTest)
     tx3.vout.resize(1);
     tx3.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx3.vout[0].nValue = 5 * COIN;
-    pool.addUnchecked(tx3.GetHash(), entry.Fee(0LL).Priority(100.0).FromTx(tx3));
+    pool.addUnchecked(tx3.GetHash(), entry.Fee(0LL).FromTx(tx3));
 
     /* 2nd highest fee */
     CMutableTransaction tx4 = CMutableTransaction();
     tx4.vout.resize(1);
     tx4.vout[0].scriptPubKey = CScript() << OP_11 << OP_EQUAL;
     tx4.vout[0].nValue = 6 * COIN;
-    pool.addUnchecked(tx4.GetHash(), entry.Fee(15000LL).Priority(1.0).FromTx(tx4));
+    pool.addUnchecked(tx4.GetHash(), entry.Fee(15000LL).FromTx(tx4));
 
     /* equal fee rate to tx1, but newer */
     CMutableTransaction tx5 = CMutableTransaction();
@@ -408,7 +407,6 @@ BOOST_AUTO_TEST_CASE(MempoolAncestorIndexingTest)
     /* set the fee to just below tx2's feerate when including ancestor */
     CAmount fee = (20000/tx2Size)*(tx7Size + tx6Size) - 1;
 
-    //CTxMemPoolEntry entry7(tx7, fee, 2, 10.0, 1, true);
     pool.addUnchecked(tx7.GetHash(), entry.Fee(fee).FromTx(tx7));
     BOOST_CHECK_EQUAL(pool.size(), 7);
     sortedOrder.insert(sortedOrder.begin()+1, tx7.GetHash().ToString());
@@ -434,7 +432,6 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
 {
     CTxMemPool pool(CFeeRate(1000));
     TestMemPoolEntryHelper entry;
-    entry.dPriority = 10.0;
 
     CMutableTransaction tx1 = CMutableTransaction();
     tx1.vin.resize(1);
@@ -442,7 +439,7 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
     tx1.vout.resize(1);
     tx1.vout[0].scriptPubKey = CScript() << OP_1 << OP_EQUAL;
     tx1.vout[0].nValue = 10 * COIN;
-    pool.addUnchecked(tx1.GetHash(), entry.Fee(10000LL).FromTx(tx1, &pool));
+    pool.addUnchecked(tx1.GetHash(), entry.Fee(10000LL).FromTx(tx1));
 
     CMutableTransaction tx2 = CMutableTransaction();
     tx2.vin.resize(1);
@@ -450,7 +447,7 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
     tx2.vout.resize(1);
     tx2.vout[0].scriptPubKey = CScript() << OP_2 << OP_EQUAL;
     tx2.vout[0].nValue = 10 * COIN;
-    pool.addUnchecked(tx2.GetHash(), entry.Fee(5000LL).FromTx(tx2, &pool));
+    pool.addUnchecked(tx2.GetHash(), entry.Fee(5000LL).FromTx(tx2));
 
     pool.TrimToSize(pool.DynamicMemoryUsage()); // should do nothing
     BOOST_CHECK(pool.exists(tx1.GetHash()));
@@ -460,7 +457,7 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
     BOOST_CHECK(pool.exists(tx1.GetHash()));
     BOOST_CHECK(!pool.exists(tx2.GetHash()));
 
-    pool.addUnchecked(tx2.GetHash(), entry.FromTx(tx2, &pool));
+    pool.addUnchecked(tx2.GetHash(), entry.FromTx(tx2));
     CMutableTransaction tx3 = CMutableTransaction();
     tx3.vin.resize(1);
     tx3.vin[0].prevout = COutPoint(tx2.GetHash(), 0);
@@ -468,7 +465,7 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
     tx3.vout.resize(1);
     tx3.vout[0].scriptPubKey = CScript() << OP_3 << OP_EQUAL;
     tx3.vout[0].nValue = 10 * COIN;
-    pool.addUnchecked(tx3.GetHash(), entry.Fee(20000LL).FromTx(tx3, &pool));
+    pool.addUnchecked(tx3.GetHash(), entry.Fee(20000LL).FromTx(tx3));
 
     pool.TrimToSize(pool.DynamicMemoryUsage() * 3 / 4); // tx3 should pay for tx2 (CPFP)
     BOOST_CHECK(!pool.exists(tx1.GetHash()));
@@ -531,10 +528,10 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
     tx7.vout[1].scriptPubKey = CScript() << OP_7 << OP_EQUAL;
     tx7.vout[1].nValue = 10 * COIN;
 
-    pool.addUnchecked(tx4.GetHash(), entry.Fee(7000LL).FromTx(tx4, &pool));
-    pool.addUnchecked(tx5.GetHash(), entry.Fee(1000LL).FromTx(tx5, &pool));
-    pool.addUnchecked(tx6.GetHash(), entry.Fee(1100LL).FromTx(tx6, &pool));
-    pool.addUnchecked(tx7.GetHash(), entry.Fee(9000LL).FromTx(tx7, &pool));
+    pool.addUnchecked(tx4.GetHash(), entry.Fee(7000LL).FromTx(tx4));
+    pool.addUnchecked(tx5.GetHash(), entry.Fee(1000LL).FromTx(tx5));
+    pool.addUnchecked(tx6.GetHash(), entry.Fee(1100LL).FromTx(tx6));
+    pool.addUnchecked(tx7.GetHash(), entry.Fee(9000LL).FromTx(tx7));
 
     // 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);
@@ -543,8 +540,8 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
     BOOST_CHECK(!pool.exists(tx7.GetHash()));
 
     if (!pool.exists(tx5.GetHash()))
-        pool.addUnchecked(tx5.GetHash(), entry.Fee(1000LL).FromTx(tx5, &pool));
-    pool.addUnchecked(tx7.GetHash(), entry.Fee(9000LL).FromTx(tx7, &pool));
+        pool.addUnchecked(tx5.GetHash(), entry.Fee(1000LL).FromTx(tx5));
+    pool.addUnchecked(tx7.GetHash(), entry.Fee(9000LL).FromTx(tx7));
 
     pool.TrimToSize(pool.DynamicMemoryUsage() / 2); // should maximize mempool size by only removing 5/7
     BOOST_CHECK(pool.exists(tx4.GetHash()));
@@ -552,8 +549,8 @@ BOOST_AUTO_TEST_CASE(MempoolSizeLimitTest)
     BOOST_CHECK(pool.exists(tx6.GetHash()));
     BOOST_CHECK(!pool.exists(tx7.GetHash()));
 
-    pool.addUnchecked(tx5.GetHash(), entry.Fee(1000LL).FromTx(tx5, &pool));
-    pool.addUnchecked(tx7.GetHash(), entry.Fee(9000LL).FromTx(tx7, &pool));
+    pool.addUnchecked(tx5.GetHash(), entry.Fee(1000LL).FromTx(tx5));
+    pool.addUnchecked(tx7.GetHash(), entry.Fee(9000LL).FromTx(tx7));
 
     std::vector<CTransactionRef> vtx;
     SetMockTime(42);
diff --git a/src/test/miner_tests.cpp b/src/test/miner_tests.cpp
index 5dbbb1b634..41f42c7b88 100644
--- a/src/test/miner_tests.cpp
+++ b/src/test/miner_tests.cpp
@@ -88,7 +88,6 @@ bool TestSequenceLocks(const CTransaction &tx, int flags)
 // Test suite for ancestor feerate transaction selection.
 // Implemented as an additional function, rather than a separate test case,
 // to allow reusing the blockchain created in CreateNewBlock_validity.
-// Note that this test assumes blockprioritysize is 0.
 void TestPackageSelection(const CChainParams& chainparams, CScript scriptPubKey, std::vector<CTransactionRef>& txFirst)
 {
     // Test the ancestor feerate transaction selection.
@@ -203,7 +202,6 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     uint256 hash;
     TestMemPoolEntryHelper entry;
     entry.nFee = 11;
-    entry.dPriority = 111.0;
     entry.nHeight = 11;
 
     LOCK(cs_main);
@@ -308,7 +306,7 @@ BOOST_AUTO_TEST_CASE(CreateNewBlock_validity)
     BOOST_CHECK_THROW(AssemblerForTest(chainparams).CreateNewBlock(scriptPubKey), std::runtime_error);
     mempool.clear();
 
-    // child with higher priority than parent
+    // child with higher feerate than parent
     tx.vin[0].scriptSig = CScript() << OP_1;
     tx.vin[0].prevout.hash = txFirst[1]->GetHash();
     tx.vout[0].nValue = BLOCKSUBSIDY-HIGHFEE;
diff --git a/src/test/policyestimator_tests.cpp b/src/test/policyestimator_tests.cpp
index 0c060801bc..d01ef7c6ee 100644
--- a/src/test/policyestimator_tests.cpp
+++ b/src/test/policyestimator_tests.cpp
@@ -56,7 +56,7 @@ BOOST_AUTO_TEST_CASE(BlockPolicyEstimates)
             for (int k = 0; k < 4; k++) { // add 4 fee txs
                 tx.vin[0].prevout.n = 10000*blocknum+100*j+k; // make transaction unique
                 uint256 hash = tx.GetHash();
-                mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Priority(0).Height(blocknum).FromTx(tx, &mpool));
+                mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Height(blocknum).FromTx(tx));
                 txHashes[j].push_back(hash);
             }
         }
@@ -132,7 +132,7 @@ BOOST_AUTO_TEST_CASE(BlockPolicyEstimates)
             for (int k = 0; k < 4; k++) { // add 4 fee txs
                 tx.vin[0].prevout.n = 10000*blocknum+100*j+k;
                 uint256 hash = tx.GetHash();
-                mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Priority(0).Height(blocknum).FromTx(tx, &mpool));
+                mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Height(blocknum).FromTx(tx));
                 txHashes[j].push_back(hash);
             }
         }
@@ -169,7 +169,7 @@ BOOST_AUTO_TEST_CASE(BlockPolicyEstimates)
             for (int k = 0; k < 4; k++) { // add 4 fee txs
                 tx.vin[0].prevout.n = 10000*blocknum+100*j+k;
                 uint256 hash = tx.GetHash();
-                mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Priority(0).Height(blocknum).FromTx(tx, &mpool));
+                mpool.addUnchecked(hash, entry.Fee(feeV[j]).Time(GetTime()).Height(blocknum).FromTx(tx));
                 CTransactionRef ptx = mpool.get(hash);
                 if (ptx)
                     block.push_back(ptx);
@@ -185,15 +185,13 @@ BOOST_AUTO_TEST_CASE(BlockPolicyEstimates)
     }
 
     // Test that if the mempool is limited, estimateSmartFee won't return a value below the mempool min fee
-    // and that estimateSmartPriority returns essentially an infinite value
-    mpool.addUnchecked(tx.GetHash(),  entry.Fee(feeV[5]).Time(GetTime()).Priority(0).Height(blocknum).FromTx(tx, &mpool));
+    mpool.addUnchecked(tx.GetHash(),  entry.Fee(feeV[5]).Time(GetTime()).Height(blocknum).FromTx(tx));
     // evict that transaction which should set a mempool min fee of minRelayTxFee + feeV[5]
     mpool.TrimToSize(1);
     BOOST_CHECK(mpool.GetMinFee(1).GetFeePerK() > feeV[5]);
     for (int i = 1; i < 10; i++) {
         BOOST_CHECK(mpool.estimateSmartFee(i).GetFeePerK() >= mpool.estimateFee(i).GetFeePerK());
         BOOST_CHECK(mpool.estimateSmartFee(i).GetFeePerK() >= mpool.GetMinFee(1).GetFeePerK());
-        BOOST_CHECK(mpool.estimateSmartPriority(i) == INF_PRIORITY);
     }
 }
 
diff --git a/src/test/test_bitcoin.cpp b/src/test/test_bitcoin.cpp
index 6039424480..2297644c0b 100644
--- a/src/test/test_bitcoin.cpp
+++ b/src/test/test_bitcoin.cpp
@@ -141,17 +141,14 @@ TestChain100Setup::~TestChain100Setup()
 }
 
 
-CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(const CMutableTransaction &tx, CTxMemPool *pool) {
+CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(const CMutableTransaction &tx) {
     CTransaction txn(tx);
-    return FromTx(txn, pool);
+    return FromTx(txn);
 }
 
-CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(const CTransaction &txn, CTxMemPool *pool) {
-    // Hack to assume either it's completely dependent on other mempool txs or not at all
-    CAmount inChainValue = pool && pool->HasNoInputsOf(txn) ? txn.GetValueOut() : 0;
-
-    return CTxMemPoolEntry(MakeTransactionRef(txn), nFee, nTime, dPriority, nHeight,
-                           inChainValue, spendsCoinbase, sigOpCost, lp);
+CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(const CTransaction &txn) {
+    return CTxMemPoolEntry(MakeTransactionRef(txn), nFee, nTime, nHeight,
+                           spendsCoinbase, sigOpCost, lp);
 }
 
 void Shutdown(void* parg)
diff --git a/src/test/test_bitcoin.h b/src/test/test_bitcoin.h
index 5ef6fa764f..a593f136eb 100644
--- a/src/test/test_bitcoin.h
+++ b/src/test/test_bitcoin.h
@@ -61,30 +61,27 @@ struct TestChain100Setup : public TestingSetup {
 };
 
 class CTxMemPoolEntry;
-class CTxMemPool;
 
 struct TestMemPoolEntryHelper
 {
     // Default values
     CAmount nFee;
     int64_t nTime;
-    double dPriority;
     unsigned int nHeight;
     bool spendsCoinbase;
     unsigned int sigOpCost;
     LockPoints lp;
 
     TestMemPoolEntryHelper() :
-        nFee(0), nTime(0), dPriority(0.0), nHeight(1),
+        nFee(0), nTime(0), nHeight(1),
         spendsCoinbase(false), sigOpCost(4) { }
     
-    CTxMemPoolEntry FromTx(const CMutableTransaction &tx, CTxMemPool *pool = NULL);
-    CTxMemPoolEntry FromTx(const CTransaction &tx, CTxMemPool *pool = NULL);
+    CTxMemPoolEntry FromTx(const CMutableTransaction &tx);
+    CTxMemPoolEntry FromTx(const CTransaction &tx);
 
     // Change the default value
     TestMemPoolEntryHelper &Fee(CAmount _fee) { nFee = _fee; return *this; }
     TestMemPoolEntryHelper &Time(int64_t _time) { nTime = _time; return *this; }
-    TestMemPoolEntryHelper &Priority(double _priority) { dPriority = _priority; return *this; }
     TestMemPoolEntryHelper &Height(unsigned int _height) { nHeight = _height; return *this; }
     TestMemPoolEntryHelper &SpendsCoinbase(bool _flag) { spendsCoinbase = _flag; return *this; }
     TestMemPoolEntryHelper &SigOpsCost(unsigned int _sigopsCost) { sigOpCost = _sigopsCost; return *this; }
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 942a6fcce7..79dd0fb5f9 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -19,22 +19,17 @@
 #include "version.h"
 
 CTxMemPoolEntry::CTxMemPoolEntry(const CTransactionRef& _tx, const CAmount& _nFee,
-                                 int64_t _nTime, double _entryPriority, unsigned int _entryHeight,
-                                 CAmount _inChainInputValue,
+                                 int64_t _nTime, unsigned int _entryHeight,
                                  bool _spendsCoinbase, int64_t _sigOpsCost, LockPoints lp):
-    tx(_tx), nFee(_nFee), nTime(_nTime), entryPriority(_entryPriority), entryHeight(_entryHeight),
-    inChainInputValue(_inChainInputValue),
+    tx(_tx), nFee(_nFee), nTime(_nTime), entryHeight(_entryHeight),
     spendsCoinbase(_spendsCoinbase), sigOpCost(_sigOpsCost), lockPoints(lp)
 {
     nTxWeight = GetTransactionWeight(*tx);
-    nModSize = tx->CalculateModifiedSize(GetTxSize());
     nUsageSize = RecursiveDynamicUsage(*tx) + memusage::DynamicUsage(tx);
 
     nCountWithDescendants = 1;
     nSizeWithDescendants = GetTxSize();
     nModFeesWithDescendants = nFee;
-    CAmount nValueIn = tx->GetValueOut()+nFee;
-    assert(inChainInputValue <= nValueIn);
 
     feeDelta = 0;
 
@@ -49,16 +44,6 @@ CTxMemPoolEntry::CTxMemPoolEntry(const CTxMemPoolEntry& other)
     *this = other;
 }
 
-double
-CTxMemPoolEntry::GetPriority(unsigned int currentHeight) const
-{
-    double deltaPriority = ((double)(currentHeight-entryHeight)*inChainInputValue)/nModSize;
-    double dResult = entryPriority + deltaPriority;
-    if (dResult < 0) // This should only happen if it was called with a height below entry height
-        dResult = 0;
-    return dResult;
-}
-
 void CTxMemPoolEntry::UpdateFeeDelta(int64_t newFeeDelta)
 {
     nModFeesWithDescendants += newFeeDelta - feeDelta;
@@ -404,11 +389,11 @@ bool CTxMemPool::addUnchecked(const uint256& hash, const CTxMemPoolEntry &entry,
     // Update transaction for any feeDelta created by PrioritiseTransaction
     // TODO: refactor so that the fee delta is calculated before inserting
     // into mapTx.
-    std::map<uint256, std::pair<double, CAmount> >::const_iterator pos = mapDeltas.find(hash);
+    std::map<uint256, CAmount>::const_iterator pos = mapDeltas.find(hash);
     if (pos != mapDeltas.end()) {
-        const std::pair<double, CAmount> &deltas = pos->second;
-        if (deltas.second) {
-            mapTx.modify(newit, update_fee_delta(deltas.second));
+        const CAmount &delta = pos->second;
+        if (delta) {
+            mapTx.modify(newit, update_fee_delta(delta));
         }
     }
 
@@ -875,16 +860,6 @@ CFeeRate CTxMemPool::estimateSmartFee(int nBlocks, int *answerFoundAtBlocks) con
     LOCK(cs);
     return minerPolicyEstimator->estimateSmartFee(nBlocks, answerFoundAtBlocks, *this);
 }
-double CTxMemPool::estimatePriority(int nBlocks) const
-{
-    LOCK(cs);
-    return minerPolicyEstimator->estimatePriority(nBlocks);
-}
-double CTxMemPool::estimateSmartPriority(int nBlocks, int *answerFoundAtBlocks) const
-{
-    LOCK(cs);
-    return minerPolicyEstimator->estimateSmartPriority(nBlocks, answerFoundAtBlocks, *this);
-}
 
 bool
 CTxMemPool::WriteFeeEstimates(CAutoFile& fileout) const
@@ -920,16 +895,15 @@ CTxMemPool::ReadFeeEstimates(CAutoFile& filein)
     return true;
 }
 
-void CTxMemPool::PrioritiseTransaction(const uint256& hash, double dPriorityDelta, const CAmount& nFeeDelta)
+void CTxMemPool::PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta)
 {
     {
         LOCK(cs);
-        std::pair<double, CAmount> &deltas = mapDeltas[hash];
-        deltas.first += dPriorityDelta;
-        deltas.second += nFeeDelta;
+        CAmount &delta = mapDeltas[hash];
+        delta += nFeeDelta;
         txiter it = mapTx.find(hash);
         if (it != mapTx.end()) {
-            mapTx.modify(it, update_fee_delta(deltas.second));
+            mapTx.modify(it, update_fee_delta(delta));
             // Now update all ancestors' modified fees with descendants
             setEntries setAncestors;
             uint64_t nNoLimit = std::numeric_limits<uint64_t>::max();
@@ -940,18 +914,17 @@ void CTxMemPool::PrioritiseTransaction(const uint256& hash, double dPriorityDelt
             }
         }
     }
-    LogPrintf("PrioritiseTransaction: %s priority += %f, fee += %d\n", hash.ToString(), dPriorityDelta, FormatMoney(nFeeDelta));
+    LogPrintf("PrioritiseTransaction: %s feerate += %s\n", hash.ToString(), FormatMoney(nFeeDelta));
 }
 
-void CTxMemPool::ApplyDeltas(const uint256 hash, double &dPriorityDelta, CAmount &nFeeDelta) const
+void CTxMemPool::ApplyDelta(const uint256 hash, CAmount &nFeeDelta) const
 {
     LOCK(cs);
-    std::map<uint256, std::pair<double, CAmount> >::const_iterator pos = mapDeltas.find(hash);
+    std::map<uint256, CAmount>::const_iterator pos = mapDeltas.find(hash);
     if (pos == mapDeltas.end())
         return;
-    const std::pair<double, CAmount> &deltas = pos->second;
-    dPriorityDelta += deltas.first;
-    nFeeDelta += deltas.second;
+    const CAmount &delta = pos->second;
+    nFeeDelta += delta;
 }
 
 void CTxMemPool::ClearPrioritisation(const uint256 hash)
diff --git a/src/txmempool.h b/src/txmempool.h
index 8a8039ded1..e919be91a9 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -29,18 +29,6 @@
 class CAutoFile;
 class CBlockIndex;
 
-inline double AllowFreeThreshold()
-{
-    return COIN * 144 / 250;
-}
-
-inline bool AllowFree(double dPriority)
-{
-    // Large (in bytes) low-priority (new, small-coin) transactions
-    // need a fee.
-    return dPriority > AllowFreeThreshold();
-}
-
 /** Fake height value used in CCoins to signify they are only in the memory pool (since 0.8) */
 static const unsigned int MEMPOOL_HEIGHT = 0x7FFFFFFF;
 
@@ -84,12 +72,9 @@ private:
     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 nModSize;           //!< ... and modified size for priority
     size_t nUsageSize;         //!< ... and total memory usage
     int64_t nTime;             //!< Local time when entering the mempool
-    double entryPriority;      //!< Priority when entering the mempool
     unsigned int entryHeight;  //!< Chain height when entering the mempool
-    CAmount inChainInputValue; //!< Sum of all txin values that are already in blockchain
     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
@@ -112,19 +97,14 @@ private:
 
 public:
     CTxMemPoolEntry(const CTransactionRef& _tx, const CAmount& _nFee,
-                    int64_t _nTime, double _entryPriority, unsigned int _entryHeight,
-                    CAmount _inChainInputValue, bool spendsCoinbase,
+                    int64_t _nTime, unsigned int _entryHeight,
+                    bool spendsCoinbase,
                     int64_t nSigOpsCost, LockPoints lp);
 
     CTxMemPoolEntry(const CTxMemPoolEntry& other);
 
     const CTransaction& GetTx() const { return *this->tx; }
     CTransactionRef GetSharedTx() const { return this->tx; }
-    /**
-     * Fast calculation of lower bound of current priority as update
-     * from entry priority. Only inputs that were originally in-chain will age.
-     */
-    double GetPriority(unsigned int currentHeight) const;
     const CAmount& GetFee() const { return nFee; }
     size_t GetTxSize() const;
     size_t GetTxWeight() const { return nTxWeight; }
@@ -512,7 +492,7 @@ private:
 
 public:
     indirectmap<COutPoint, const CTransaction*> mapNextTx;
-    std::map<uint256, std::pair<double, CAmount> > mapDeltas;
+    std::map<uint256, CAmount> mapDeltas;
 
     /** Create a new CTxMemPool.
      */
@@ -554,8 +534,8 @@ public:
     bool HasNoInputsOf(const CTransaction& tx) const;
 
     /** Affect CreateNewBlock prioritisation of transactions */
-    void PrioritiseTransaction(const uint256& hash, double dPriorityDelta, const CAmount& nFeeDelta);
-    void ApplyDeltas(const uint256 hash, double &dPriorityDelta, CAmount &nFeeDelta) const;
+    void PrioritiseTransaction(const uint256& hash, const CAmount& nFeeDelta);
+    void ApplyDelta(const uint256 hash, CAmount &nFeeDelta) const;
     void ClearPrioritisation(const uint256 hash);
 
 public:
@@ -647,15 +627,6 @@ public:
     /** Estimate fee rate needed to get into the next nBlocks */
     CFeeRate estimateFee(int nBlocks) const;
 
-    /** Estimate priority needed to get into the next nBlocks
-     *  If no answer can be given at nBlocks, return an estimate
-     *  at the lowest number of blocks where one can be given
-     */
-    double estimateSmartPriority(int nBlocks, int *answerFoundAtBlocks = NULL) const;
-
-    /** Estimate priority needed to get into the next nBlocks */
-    double estimatePriority(int nBlocks) const;
-    
     /** Write/Read estimates to disk */
     bool WriteFeeEstimates(CAutoFile& fileout) const;
     bool ReadFeeEstimates(CAutoFile& filein);
@@ -719,17 +690,4 @@ public:
     bool HaveCoins(const uint256 &txid) const;
 };
 
-// We want to sort transactions by coin age priority
-typedef std::pair<double, CTxMemPool::txiter> TxCoinAgePriority;
-
-struct TxCoinAgePriorityCompare
-{
-    bool operator()(const TxCoinAgePriority& a, const TxCoinAgePriority& b)
-    {
-        if (a.first == b.first)
-            return CompareTxMemPoolEntryByScore()(*(b.second), *(a.second)); //Reverse order to make sort less than
-        return a.first < b.first;
-    }
-};
-
 #endif // BITCOIN_TXMEMPOOL_H
diff --git a/src/validation.cpp b/src/validation.cpp
index e09eba1aca..28013306d2 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -720,11 +720,7 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
         CAmount nFees = nValueIn-nValueOut;
         // nModifiedFees includes any fee deltas from PrioritiseTransaction
         CAmount nModifiedFees = nFees;
-        double nPriorityDummy = 0;
-        pool.ApplyDeltas(hash, nPriorityDummy, nModifiedFees);
-
-        CAmount inChainInputValue;
-        double dPriority = view.GetPriority(tx, chainActive.Height(), inChainInputValue);
+        pool.ApplyDelta(hash, nModifiedFees);
 
         // Keep track of transactions that spend a coinbase, which we re-scan
         // during reorgs to ensure COINBASE_MATURITY is still met.
@@ -737,8 +733,8 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
             }
         }
 
-        CTxMemPoolEntry entry(ptx, nFees, nAcceptTime, dPriority, chainActive.Height(),
-                              inChainInputValue, fSpendsCoinbase, nSigOpsCost, lp);
+        CTxMemPoolEntry entry(ptx, nFees, nAcceptTime, chainActive.Height(),
+                              fSpendsCoinbase, nSigOpsCost, lp);
         unsigned int nSize = entry.GetTxSize();
 
         // Check that the transaction doesn't have an excessive number of
@@ -753,32 +749,11 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
         CAmount mempoolRejectFee = pool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(nSize);
         if (mempoolRejectFee > 0 && nModifiedFees < mempoolRejectFee) {
             return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool min fee not met", false, strprintf("%d < %d", nFees, mempoolRejectFee));
-        } else if (GetBoolArg("-relaypriority", DEFAULT_RELAYPRIORITY) && nModifiedFees < ::minRelayTxFee.GetFee(nSize) && !AllowFree(entry.GetPriority(chainActive.Height() + 1))) {
-            // Require that free transactions have sufficient priority to be mined in the next block.
-            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "insufficient priority");
         }
 
-        // Continuously rate-limit free (really, very-low-fee) transactions
-        // This mitigates 'penny-flooding' -- sending thousands of free transactions just to
-        // be annoying or make others' transactions take longer to confirm.
-        if (fLimitFree && nModifiedFees < ::minRelayTxFee.GetFee(nSize))
-        {
-            static CCriticalSection csFreeLimiter;
-            static double dFreeCount;
-            static int64_t nLastTime;
-            int64_t nNow = GetTime();
-
-            LOCK(csFreeLimiter);
-
-            // Use an exponentially decaying ~10-minute window:
-            dFreeCount *= pow(1.0 - 1.0/600.0, (double)(nNow - nLastTime));
-            nLastTime = nNow;
-            // -limitfreerelay unit is thousand-bytes-per-minute
-            // At default rate it would take over a month to fill 1GB
-            if (dFreeCount + nSize >= GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY) * 10 * 1000)
-                return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "rate limited free transaction");
-            LogPrint("mempool", "Rate limit dFreeCount: %g => %g\n", dFreeCount, dFreeCount+nSize);
-            dFreeCount += nSize;
+        // No transactions are allowed below minRelayTxFee except from disconnected blocks
+        if (fLimitFree && nModifiedFees < ::minRelayTxFee.GetFee(nSize)) {
+            return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "min relay fee not met");
         }
 
         if (nAbsurdFee && nFees > nAbsurdFee)
@@ -4205,7 +4180,6 @@ bool LoadMempool(void)
         }
         uint64_t num;
         file >> num;
-        double prioritydummy = 0;
         while (num--) {
             CTransactionRef tx;
             int64_t nTime;
@@ -4216,7 +4190,7 @@ bool LoadMempool(void)
 
             CAmount amountdelta = nFeeDelta;
             if (amountdelta) {
-                mempool.PrioritiseTransaction(tx->GetHash(), prioritydummy, amountdelta);
+                mempool.PrioritiseTransaction(tx->GetHash(), amountdelta);
             }
             CValidationState state;
             if (nTime + nExpiryTimeout > nNow) {
@@ -4237,7 +4211,7 @@ bool LoadMempool(void)
         file >> mapDeltas;
 
         for (const auto& i : mapDeltas) {
-            mempool.PrioritiseTransaction(i.first, prioritydummy, i.second);
+            mempool.PrioritiseTransaction(i.first, i.second);
         }
     } catch (const std::exception& e) {
         LogPrintf("Failed to deserialize mempool data on disk: %s. Continuing anyway.\n", e.what());
@@ -4258,7 +4232,7 @@ void DumpMempool(void)
     {
         LOCK(mempool.cs);
         for (const auto &i : mempool.mapDeltas) {
-            mapDeltas[i.first] = i.second.second;
+            mapDeltas[i.first] = i.second;
         }
         vinfo = mempool.infoAll();
     }
diff --git a/src/validation.h b/src/validation.h
index 9c606f2419..43f0dbae34 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -122,8 +122,6 @@ static const int64_t BLOCK_DOWNLOAD_TIMEOUT_BASE = 1000000;
 /** Additional block download timeout per parallel downloading peer (i.e. 5 min) */
 static const int64_t BLOCK_DOWNLOAD_TIMEOUT_PER_PEER = 500000;
 
-static const unsigned int DEFAULT_LIMITFREERELAY = 0;
-static const bool DEFAULT_RELAYPRIORITY = true;
 static const int64_t DEFAULT_MAX_TIP_AGE = 24 * 60 * 60;
 /** Maximum age of our tip in seconds for us to be considered current for fee estimation */
 static const int64_t MAX_FEE_ESTIMATION_TIP_AGE = 3 * 60 * 60;
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index b7c2d8ea8d..dc3e0e28d1 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -40,7 +40,6 @@ CWallet* pwalletMain = NULL;
 CFeeRate payTxFee(DEFAULT_TRANSACTION_FEE);
 unsigned int nTxConfirmTarget = DEFAULT_TX_CONFIRM_TARGET;
 bool bSpendZeroConfChange = DEFAULT_SPEND_ZEROCONF_CHANGE;
-bool fSendFreeTransactions = DEFAULT_SEND_FREE_TRANSACTIONS;
 bool fWalletRbf = DEFAULT_WALLET_RBF;
 
 const char * DEFAULT_WALLET_DAT = "wallet.dat";
@@ -2379,7 +2378,6 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wt
                 CAmount nValueToSelect = nValue;
                 if (nSubtractFeeFromAmount == 0)
                     nValueToSelect += nFeeRet;
-                double dPriority = 0;
                 // vouts to the payees
                 for (const auto& recipient : vecSend)
                 {
@@ -2420,19 +2418,6 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wt
                     strFailReason = _("Insufficient funds");
                     return false;
                 }
-                for (const auto& pcoin : setCoins)
-                {
-                    CAmount nCredit = pcoin.first->tx->vout[pcoin.second].nValue;
-                    //The coin age after the next block (depth+1) is used instead of the current,
-                    //reflecting an assumption the user would accept a bit more delay for
-                    //a chance at a free transaction.
-                    //But mempool inputs might still be in the mempool, so their age stays 0
-                    int age = pcoin.first->GetDepthInMainChain();
-                    assert(age >= 0);
-                    if (age != 0)
-                        age += 1;
-                    dPriority += (double)nCredit * age;
-                }
 
                 const CAmount nChange = nValueIn - nValueToSelect;
                 if (nChange > 0)
@@ -2544,7 +2529,6 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wt
                 unsigned int nBytes = GetVirtualTransactionSize(txNew);
 
                 CTransaction txNewConst(txNew);
-                dPriority = txNewConst.ComputePriority(dPriority, nBytes);
 
                 // Remove scriptSigs to eliminate the fee calculation dummy signatures
                 for (auto& vin : txNew.vin) {
@@ -2557,16 +2541,6 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wt
                 if (coinControl && coinControl->nConfirmTarget > 0)
                     currentConfirmationTarget = coinControl->nConfirmTarget;
 
-                // Can we complete this as a free transaction?
-                if (fSendFreeTransactions && nBytes <= MAX_FREE_TRANSACTION_CREATE_SIZE)
-                {
-                    // Not enough fee: enough priority?
-                    double dPriorityNeeded = mempool.estimateSmartPriority(currentConfirmationTarget);
-                    // Require at least hard-coded AllowFree.
-                    if (dPriority >= dPriorityNeeded && AllowFree(dPriority))
-                        break;
-                }
-
                 CAmount nFeeNeeded = GetMinimumFee(nBytes, currentConfirmationTarget, mempool);
                 if (coinControl && nFeeNeeded > 0 && coinControl->nMinimumTotalFee > nFeeNeeded) {
                     nFeeNeeded = coinControl->nMinimumTotalFee;
@@ -2655,7 +2629,7 @@ bool CWallet::CreateTransaction(const vector<CRecipient>& vecSend, CWalletTx& wt
     if (GetBoolArg("-walletrejectlongchains", DEFAULT_WALLET_REJECT_LONG_CHAINS)) {
         // Lastly, ensure this tx will pass the mempool's chain limits
         LockPoints lp;
-        CTxMemPoolEntry entry(wtxNew.tx, 0, 0, 0, 0, 0, false, 0, lp);
+        CTxMemPoolEntry entry(wtxNew.tx, 0, 0, 0, false, 0, lp);
         CTxMemPool::setEntries setAncestors;
         size_t nLimitAncestors = GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
         size_t nLimitAncestorSize = GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT)*1000;
@@ -3548,8 +3522,6 @@ std::string CWallet::GetWalletHelpString(bool showDebug)
                                                             CURRENCY_UNIT, FormatMoney(payTxFee.GetFeePerK())));
     strUsage += HelpMessageOpt("-rescan", _("Rescan the block chain for missing wallet transactions on startup"));
     strUsage += HelpMessageOpt("-salvagewallet", _("Attempt to recover private keys from a corrupt wallet on startup"));
-    if (showDebug)
-        strUsage += HelpMessageOpt("-sendfreetransactions", strprintf(_("Send transactions as zero-fee transactions if possible (default: %u)"), DEFAULT_SEND_FREE_TRANSACTIONS));
     strUsage += HelpMessageOpt("-spendzeroconfchange", strprintf(_("Spend unconfirmed change when sending transactions (default: %u)"), DEFAULT_SPEND_ZEROCONF_CHANGE));
     strUsage += HelpMessageOpt("-txconfirmtarget=<n>", strprintf(_("If paytxfee is not set, include enough fee so transactions begin confirmation on average within n blocks (default: %u)"), DEFAULT_TX_CONFIRM_TARGET));
     strUsage += HelpMessageOpt("-usehd", _("Use hierarchical deterministic key generation (HD) after BIP32. Only has effect during wallet creation/first start") + " " + strprintf(_("(default: %u)"), DEFAULT_USE_HD_WALLET));
@@ -3870,12 +3842,8 @@ bool CWallet::ParameterInteraction()
     }
     nTxConfirmTarget = GetArg("-txconfirmtarget", DEFAULT_TX_CONFIRM_TARGET);
     bSpendZeroConfChange = GetBoolArg("-spendzeroconfchange", DEFAULT_SPEND_ZEROCONF_CHANGE);
-    fSendFreeTransactions = GetBoolArg("-sendfreetransactions", DEFAULT_SEND_FREE_TRANSACTIONS);
     fWalletRbf = GetBoolArg("-walletrbf", DEFAULT_WALLET_RBF);
 
-    if (fSendFreeTransactions && GetArg("-limitfreerelay", DEFAULT_LIMITFREERELAY) <= 0)
-        return InitError("Creation of free transactions with their relay disabled is not supported.");
-
     return true;
 }
 
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 02c1b18769..9f89c89bc2 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -38,7 +38,6 @@ extern CWallet* pwalletMain;
 extern CFeeRate payTxFee;
 extern unsigned int nTxConfirmTarget;
 extern bool bSpendZeroConfChange;
-extern bool fSendFreeTransactions;
 extern bool fWalletRbf;
 
 static const unsigned int DEFAULT_KEYPOOL_SIZE = 100;
@@ -56,16 +55,12 @@ static const CAmount MIN_CHANGE = CENT;
 static const CAmount MIN_FINAL_CHANGE = MIN_CHANGE/2;
 //! Default for -spendzeroconfchange
 static const bool DEFAULT_SPEND_ZEROCONF_CHANGE = true;
-//! Default for -sendfreetransactions
-static const bool DEFAULT_SEND_FREE_TRANSACTIONS = false;
 //! Default for -walletrejectlongchains
 static const bool DEFAULT_WALLET_REJECT_LONG_CHAINS = false;
 //! -txconfirmtarget default
 static const unsigned int DEFAULT_TX_CONFIRM_TARGET = 6;
 //! -walletrbf default
 static const bool DEFAULT_WALLET_RBF = false;
-//! Largest (in bytes) free transaction we're willing to create
-static const unsigned int MAX_FREE_TRANSACTION_CREATE_SIZE = 1000;
 static const bool DEFAULT_WALLETBROADCAST = true;
 static const bool DEFAULT_DISABLE_WALLET = false;
 //! if set, all keys will be derived by using BIP32