mempool,rpc: add removetx rpc method (#7047)

Addresses one of the concerns with #7041.

Provides a mechanism (via the RPC interface) to delete a single transaction, described by its hash, from the mempool. The method returns an error if the transaction cannot be found. Once the transaction is removed it remains in the cache and cannot be resubmitted until the cache is cleared or it expires from the cache.

CHANGELOG_PENDING.md

@@ -30,6 +30,8 @@ Special thanks to external contributors on this release:
 
 ### FEATURES
 
+- [mempool, rpc] \#7041  Add removeTx operation to the RPC layer. (@tychoish)
+
 ### IMPROVEMENTS
 
 ### BUG FIXES

internal/consensus/replay_stubs.go

@@ -24,6 +24,7 @@ func (emptyMempool) Size() int { return 0 }
 func (emptyMempool) CheckTx(_ context.Context, _ types.Tx, _ func(*abci.Response), _ mempool.TxInfo) error {
 	return nil
 }
+func (emptyMempool) RemoveTxByKey(txKey types.TxKey) error   { return nil }
 func (emptyMempool) ReapMaxBytesMaxGas(_, _ int64) types.Txs { return types.Txs{} }
 func (emptyMempool) ReapMaxTxs(n int) types.Txs              { return types.Txs{} }
 func (emptyMempool) Update(

internal/mempool/cache.go

@@ -31,14 +31,14 @@ var _ TxCache = (*LRUTxCache)(nil)
 type LRUTxCache struct {
 	mtx      tmsync.Mutex
 	size     int
-	cacheMap map[[TxKeySize]byte]*list.Element
+	cacheMap map[types.TxKey]*list.Element
 	list     *list.List
 }
 
 func NewLRUTxCache(cacheSize int) *LRUTxCache {
 	return &LRUTxCache{
 		size:     cacheSize,
-		cacheMap: make(map[[TxKeySize]byte]*list.Element, cacheSize),
+		cacheMap: make(map[types.TxKey]*list.Element, cacheSize),
 		list:     list.New(),
 	}
 }
@@ -53,7 +53,7 @@ func (c *LRUTxCache) Reset() {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 
-	c.cacheMap = make(map[[TxKeySize]byte]*list.Element, c.size)
+	c.cacheMap = make(map[types.TxKey]*list.Element, c.size)
 	c.list.Init()
 }
 
@@ -61,7 +61,7 @@ func (c *LRUTxCache) Push(tx types.Tx) bool {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 
-	key := TxKey(tx)
+	key := tx.Key()
 
 	moved, ok := c.cacheMap[key]
 	if ok {
@@ -72,7 +72,7 @@ func (c *LRUTxCache) Push(tx types.Tx) bool {
 	if c.list.Len() >= c.size {
 		front := c.list.Front()
 		if front != nil {
-			frontKey := front.Value.([TxKeySize]byte)
+			frontKey := front.Value.(types.TxKey)
 			delete(c.cacheMap, frontKey)
 			c.list.Remove(front)
 		}
@@ -88,7 +88,7 @@ func (c *LRUTxCache) Remove(tx types.Tx) {
 	c.mtx.Lock()
 	defer c.mtx.Unlock()
 
-	key := TxKey(tx)
+	key := tx.Key()
 	e := c.cacheMap[key]
 	delete(c.cacheMap, key)
 

internal/mempool/mempool.go

@@ -32,6 +32,10 @@ type Mempool interface {
 	// its validity and whether it should be added to the mempool.
 	CheckTx(ctx context.Context, tx types.Tx, callback func(*abci.Response), txInfo TxInfo) error
 
+	// RemoveTxByKey removes a transaction, identified by its key,
+	// from the mempool.
+	RemoveTxByKey(txKey types.TxKey) error
+
 	// ReapMaxBytesMaxGas reaps transactions from the mempool up to maxBytes
 	// bytes total with the condition that the total gasWanted must be less than
 	// maxGas.

internal/mempool/mock/mempool.go

@@ -20,6 +20,7 @@ func (Mempool) Size() int { return 0 }
 func (Mempool) CheckTx(_ context.Context, _ types.Tx, _ func(*abci.Response), _ mempool.TxInfo) error {
 	return nil
 }
+func (Mempool) RemoveTxByKey(txKey types.TxKey) error   { return nil }
 func (Mempool) ReapMaxBytesMaxGas(_, _ int64) types.Txs { return types.Txs{} }
 func (Mempool) ReapMaxTxs(n int) types.Txs              { return types.Txs{} }
 func (Mempool) Update(

internal/mempool/tx.go

@@ -1,24 +1,9 @@
 package mempool
 
 import (
-	"crypto/sha256"
-
 	"github.com/tendermint/tendermint/types"
 )
 
-// TxKeySize defines the size of the transaction's key used for indexing.
-const TxKeySize = sha256.Size
-
-// TxKey is the fixed length array key used as an index.
-func TxKey(tx types.Tx) [TxKeySize]byte {
-	return sha256.Sum256(tx)
-}
-
-// TxHashFromBytes returns the hash of a transaction from raw bytes.
-func TxHashFromBytes(tx []byte) []byte {
-	return types.Tx(tx).Hash()
-}
-
 // TxInfo are parameters that get passed when attempting to add a tx to the
 // mempool.
 type TxInfo struct {

internal/mempool/v0/cache_test.go

@@ -61,7 +61,7 @@ func TestCacheAfterUpdate(t *testing.T) {
 			require.NotEqual(t, len(tc.txsInCache), counter,
 				"cache larger than expected on testcase %d", tcIndex)
 
-			nodeVal := node.Value.([sha256.Size]byte)
+			nodeVal := node.Value.(types.TxKey)
 			expectedBz := sha256.Sum256([]byte{byte(tc.txsInCache[len(tc.txsInCache)-counter-1])})
 			// Reference for reading the errors:
 			// >>> sha256('\x00').hexdigest()
@@ -71,7 +71,7 @@ func TestCacheAfterUpdate(t *testing.T) {
 			// >>> sha256('\x02').hexdigest()
 			// 'dbc1b4c900ffe48d575b5da5c638040125f65db0fe3e24494b76ea986457d986'
 
-			require.Equal(t, expectedBz, nodeVal, "Equality failed on index %d, tc %d", counter, tcIndex)
+			require.EqualValues(t, expectedBz, nodeVal, "Equality failed on index %d, tc %d", counter, tcIndex)
 			counter++
 			node = node.Next()
 		}

internal/mempool/v0/clist_mempool.go

@@ -3,6 +3,7 @@ package v0
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"sync"
 	"sync/atomic"
@@ -240,7 +241,7 @@ func (mem *CListMempool) CheckTx(
 		// Note it's possible a tx is still in the cache but no longer in the mempool
 		// (eg. after committing a block, txs are removed from mempool but not cache),
 		// so we only record the sender for txs still in the mempool.
-		if e, ok := mem.txsMap.Load(mempool.TxKey(tx)); ok {
+		if e, ok := mem.txsMap.Load(tx.Key()); ok {
 			memTx := e.(*clist.CElement).Value.(*mempoolTx)
 			_, loaded := memTx.senders.LoadOrStore(txInfo.SenderID, true)
 			// TODO: consider punishing peer for dups,
@@ -327,7 +328,7 @@ func (mem *CListMempool) reqResCb(
 //  - resCbFirstTime (lock not held) if tx is valid
 func (mem *CListMempool) addTx(memTx *mempoolTx) {
 	e := mem.txs.PushBack(memTx)
-	mem.txsMap.Store(mempool.TxKey(memTx.tx), e)
+	mem.txsMap.Store(memTx.tx.Key(), e)
 	atomic.AddInt64(&mem.txsBytes, int64(len(memTx.tx)))
 	mem.metrics.TxSizeBytes.Observe(float64(len(memTx.tx)))
 }
@@ -338,7 +339,7 @@ func (mem *CListMempool) addTx(memTx *mempoolTx) {
 func (mem *CListMempool) removeTx(tx types.Tx, elem *clist.CElement, removeFromCache bool) {
 	mem.txs.Remove(elem)
 	elem.DetachPrev()
-	mem.txsMap.Delete(mempool.TxKey(tx))
+	mem.txsMap.Delete(tx.Key())
 	atomic.AddInt64(&mem.txsBytes, int64(-len(tx)))
 
 	if removeFromCache {
@@ -347,13 +348,16 @@ func (mem *CListMempool) removeTx(tx types.Tx, elem *clist.CElement, removeFromC
 }
 
 // RemoveTxByKey removes a transaction from the mempool by its TxKey index.
-func (mem *CListMempool) RemoveTxByKey(txKey [mempool.TxKeySize]byte, removeFromCache bool) {
+func (mem *CListMempool) RemoveTxByKey(txKey types.TxKey) error {
 	if e, ok := mem.txsMap.Load(txKey); ok {
 		memTx := e.(*clist.CElement).Value.(*mempoolTx)
 		if memTx != nil {
-			mem.removeTx(memTx.tx, e.(*clist.CElement), removeFromCache)
+			mem.removeTx(memTx.tx, e.(*clist.CElement), false)
+			return nil
 		}
+		return errors.New("transaction not found")
 	}
+	return errors.New("invalid transaction found")
 }
 
 func (mem *CListMempool) isFull(txSize int) error {
@@ -409,7 +413,7 @@ func (mem *CListMempool) resCbFirstTime(
 			mem.addTx(memTx)
 			mem.logger.Debug(
 				"added good transaction",
-				"tx", mempool.TxHashFromBytes(tx),
+				"tx", types.Tx(tx).Hash(),
 				"res", r,
 				"height", memTx.height,
 				"total", mem.Size(),
@@ -419,7 +423,7 @@ func (mem *CListMempool) resCbFirstTime(
 			// ignore bad transaction
 			mem.logger.Debug(
 				"rejected bad transaction",
-				"tx", mempool.TxHashFromBytes(tx),
+				"tx", types.Tx(tx).Hash(),
 				"peerID", peerP2PID,
 				"res", r,
 				"err", postCheckErr,
@@ -460,7 +464,7 @@ func (mem *CListMempool) resCbRecheck(req *abci.Request, res *abci.Response) {
 			// Good, nothing to do.
 		} else {
 			// Tx became invalidated due to newly committed block.
-			mem.logger.Debug("tx is no longer valid", "tx", mempool.TxHashFromBytes(tx), "res", r, "err", postCheckErr)
+			mem.logger.Debug("tx is no longer valid", "tx", types.Tx(tx).Hash(), "res", r, "err", postCheckErr)
 			// NOTE: we remove tx from the cache because it might be good later
 			mem.removeTx(tx, mem.recheckCursor, !mem.config.KeepInvalidTxsInCache)
 		}
@@ -598,7 +602,7 @@ func (mem *CListMempool) Update(
 		// Mempool after:
 		//   100
 		// https://github.com/tendermint/tendermint/issues/3322.
-		if e, ok := mem.txsMap.Load(mempool.TxKey(tx)); ok {
+		if e, ok := mem.txsMap.Load(tx.Key()); ok {
 			mem.removeTx(tx, e.(*clist.CElement), false)
 		}
 	}

internal/mempool/v0/clist_mempool_test.go

@@ -544,9 +544,9 @@ func TestMempoolTxsBytes(t *testing.T) {
 	err = mp.CheckTx(context.Background(), []byte{0x06}, nil, mempool.TxInfo{})
 	require.NoError(t, err)
 	assert.EqualValues(t, 9, mp.SizeBytes())
-	mp.RemoveTxByKey(mempool.TxKey([]byte{0x07}), true)
+	assert.Error(t, mp.RemoveTxByKey(types.Tx([]byte{0x07}).Key()))
 	assert.EqualValues(t, 9, mp.SizeBytes())
-	mp.RemoveTxByKey(mempool.TxKey([]byte{0x06}), true)
+	assert.NoError(t, mp.RemoveTxByKey(types.Tx([]byte{0x06}).Key()))
 	assert.EqualValues(t, 8, mp.SizeBytes())
 
 }

internal/mempool/v0/reactor.go

@@ -171,7 +171,7 @@ func (r *Reactor) handleMempoolMessage(envelope p2p.Envelope) error {
 
 		for _, tx := range protoTxs {
 			if err := r.mempool.CheckTx(context.Background(), types.Tx(tx), nil, txInfo); err != nil {
-				logger.Error("checktx failed for tx", "tx", fmt.Sprintf("%X", mempool.TxHashFromBytes(tx)), "err", err)
+				logger.Error("checktx failed for tx", "tx", fmt.Sprintf("%X", types.Tx(tx).Hash()), "err", err)
 			}
 		}
 
@@ -378,7 +378,7 @@ func (r *Reactor) broadcastTxRoutine(peerID types.NodeID, closer *tmsync.Closer)
 			}
 			r.Logger.Debug(
 				"gossiped tx to peer",
-				"tx", fmt.Sprintf("%X", mempool.TxHashFromBytes(memTx.tx)),
+				"tx", fmt.Sprintf("%X", memTx.tx.Hash()),
 				"peer", peerID,
 			)
 		}

internal/mempool/v1/mempool.go

@@ -3,6 +3,7 @@ package v1
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"sync/atomic"
 	"time"
@@ -256,7 +257,7 @@ func (txmp *TxMempool) CheckTx(
 		return err
 	}
 
-	txHash := mempool.TxKey(tx)
+	txHash := tx.Key()
 
 	// We add the transaction to the mempool's cache and if the transaction already
 	// exists, i.e. false is returned, then we check if we've seen this transaction
@@ -304,6 +305,19 @@ func (txmp *TxMempool) CheckTx(
 	return nil
 }
 
+func (txmp *TxMempool) RemoveTxByKey(txKey types.TxKey) error {
+	txmp.Lock()
+	defer txmp.Unlock()
+
+	// remove the committed transaction from the transaction store and indexes
+	if wtx := txmp.txStore.GetTxByHash(txKey); wtx != nil {
+		txmp.removeTx(wtx, false)
+		return nil
+	}
+
+	return errors.New("transaction not found")
+}
+
 // Flush flushes out the mempool. It acquires a read-lock, fetches all the
 // transactions currently in the transaction store and removes each transaction
 // from the store and all indexes and finally resets the cache.
@@ -451,7 +465,7 @@ func (txmp *TxMempool) Update(
 		}
 
 		// remove the committed transaction from the transaction store and indexes
-		if wtx := txmp.txStore.GetTxByHash(mempool.TxKey(tx)); wtx != nil {
+		if wtx := txmp.txStore.GetTxByHash(tx.Key()); wtx != nil {
 			txmp.removeTx(wtx, false)
 		}
 	}
@@ -629,7 +643,7 @@ func (txmp *TxMempool) defaultTxCallback(req *abci.Request, res *abci.Response)
 		tx := req.GetCheckTx().Tx
 		wtx := txmp.recheckCursor.Value.(*WrappedTx)
 		if !bytes.Equal(tx, wtx.tx) {
-			panic(fmt.Sprintf("re-CheckTx transaction mismatch; got: %X, expected: %X", wtx.tx.Hash(), mempool.TxKey(tx)))
+			panic(fmt.Sprintf("re-CheckTx transaction mismatch; got: %X, expected: %X", wtx.tx.Hash(), types.Tx(tx).Key()))
 		}
 
 		// Only evaluate transactions that have not been removed. This can happen
@@ -647,7 +661,7 @@ func (txmp *TxMempool) defaultTxCallback(req *abci.Request, res *abci.Response)
 				txmp.logger.Debug(
 					"existing transaction no longer valid; failed re-CheckTx callback",
 					"priority", wtx.priority,
-					"tx", fmt.Sprintf("%X", mempool.TxHashFromBytes(wtx.tx)),
+					"tx", fmt.Sprintf("%X", wtx.tx.Hash()),
 					"err", err,
 					"code", checkTxRes.CheckTx.Code,
 				)
@@ -784,13 +798,13 @@ func (txmp *TxMempool) removeTx(wtx *WrappedTx, removeFromCache bool) {
 // the height and time based indexes.
 func (txmp *TxMempool) purgeExpiredTxs(blockHeight int64) {
 	now := time.Now()
-	expiredTxs := make(map[[mempool.TxKeySize]byte]*WrappedTx)
+	expiredTxs := make(map[types.TxKey]*WrappedTx)
 
 	if txmp.config.TTLNumBlocks > 0 {
 		purgeIdx := -1
 		for i, wtx := range txmp.heightIndex.txs {
 			if (blockHeight - wtx.height) > txmp.config.TTLNumBlocks {
-				expiredTxs[mempool.TxKey(wtx.tx)] = wtx
+				expiredTxs[wtx.tx.Key()] = wtx
 				purgeIdx = i
 			} else {
 				// since the index is sorted, we know no other txs can be be purged
@@ -807,7 +821,7 @@ func (txmp *TxMempool) purgeExpiredTxs(blockHeight int64) {
 		purgeIdx := -1
 		for i, wtx := range txmp.timestampIndex.txs {
 			if now.Sub(wtx.timestamp) > txmp.config.TTLDuration {
-				expiredTxs[mempool.TxKey(wtx.tx)] = wtx
+				expiredTxs[wtx.tx.Key()] = wtx
 				purgeIdx = i
 			} else {
 				// since the index is sorted, we know no other txs can be be purged

internal/mempool/v1/mempool_test.go

@@ -226,10 +226,10 @@ func TestTxMempool_ReapMaxBytesMaxGas(t *testing.T) {
 	require.Equal(t, len(tTxs), txmp.Size())
 	require.Equal(t, int64(5690), txmp.SizeBytes())
 
-	txMap := make(map[[mempool.TxKeySize]byte]testTx)
+	txMap := make(map[types.TxKey]testTx)
 	priorities := make([]int64, len(tTxs))
 	for i, tTx := range tTxs {
-		txMap[mempool.TxKey(tTx.tx)] = tTx
+		txMap[tTx.tx.Key()] = tTx
 		priorities[i] = tTx.priority
 	}
 
@@ -241,7 +241,7 @@ func TestTxMempool_ReapMaxBytesMaxGas(t *testing.T) {
 	ensurePrioritized := func(reapedTxs types.Txs) {
 		reapedPriorities := make([]int64, len(reapedTxs))
 		for i, rTx := range reapedTxs {
-			reapedPriorities[i] = txMap[mempool.TxKey(rTx)].priority
+			reapedPriorities[i] = txMap[rTx.Key()].priority
 		}
 
 		require.Equal(t, priorities[:len(reapedPriorities)], reapedPriorities)
@@ -276,10 +276,10 @@ func TestTxMempool_ReapMaxTxs(t *testing.T) {
 	require.Equal(t, len(tTxs), txmp.Size())
 	require.Equal(t, int64(5690), txmp.SizeBytes())
 
-	txMap := make(map[[mempool.TxKeySize]byte]testTx)
+	txMap := make(map[types.TxKey]testTx)
 	priorities := make([]int64, len(tTxs))
 	for i, tTx := range tTxs {
-		txMap[mempool.TxKey(tTx.tx)] = tTx
+		txMap[tTx.tx.Key()] = tTx
 		priorities[i] = tTx.priority
 	}
 
@@ -291,7 +291,7 @@ func TestTxMempool_ReapMaxTxs(t *testing.T) {
 	ensurePrioritized := func(reapedTxs types.Txs) {
 		reapedPriorities := make([]int64, len(reapedTxs))
 		for i, rTx := range reapedTxs {
-			reapedPriorities[i] = txMap[mempool.TxKey(rTx)].priority
+			reapedPriorities[i] = txMap[rTx.Key()].priority
 		}
 
 		require.Equal(t, priorities[:len(reapedPriorities)], reapedPriorities)

internal/mempool/v1/reactor.go

@@ -178,7 +178,7 @@ func (r *Reactor) handleMempoolMessage(envelope p2p.Envelope) error {
 
 		for _, tx := range protoTxs {
 			if err := r.mempool.CheckTx(context.Background(), types.Tx(tx), nil, txInfo); err != nil {
-				logger.Error("checktx failed for tx", "tx", fmt.Sprintf("%X", mempool.TxHashFromBytes(tx)), "err", err)
+				logger.Error("checktx failed for tx", "tx", fmt.Sprintf("%X", types.Tx(tx).Hash()), "err", err)
 			}
 		}
 
@@ -386,7 +386,7 @@ func (r *Reactor) broadcastTxRoutine(peerID types.NodeID, closer *tmsync.Closer)
 			}
 			r.Logger.Debug(
 				"gossiped tx to peer",
-				"tx", fmt.Sprintf("%X", mempool.TxHashFromBytes(memTx.tx)),
+				"tx", fmt.Sprintf("%X", memTx.tx.Hash()),
 				"peer", peerID,
 			)
 		}

internal/mempool/v1/tx.go

@@ -6,7 +6,6 @@ import (
 
 	"github.com/tendermint/tendermint/internal/libs/clist"
 	tmsync "github.com/tendermint/tendermint/internal/libs/sync"
-	"github.com/tendermint/tendermint/internal/mempool"
 	"github.com/tendermint/tendermint/types"
 )
 
@@ -17,7 +16,7 @@ type WrappedTx struct {
 	tx types.Tx
 
 	// hash defines the transaction hash and the primary key used in the mempool
-	hash [mempool.TxKeySize]byte
+	hash types.TxKey
 
 	// height defines the height at which the transaction was validated at
 	height int64
@@ -66,14 +65,14 @@ func (wtx *WrappedTx) Size() int {
 //   need mutative access.
 type TxStore struct {
 	mtx       tmsync.RWMutex
-	hashTxs   map[[mempool.TxKeySize]byte]*WrappedTx // primary index
-	senderTxs map[string]*WrappedTx                  // sender is defined by the ABCI application
+	hashTxs   map[types.TxKey]*WrappedTx // primary index
+	senderTxs map[string]*WrappedTx      // sender is defined by the ABCI application
 }
 
 func NewTxStore() *TxStore {
 	return &TxStore{
 		senderTxs: make(map[string]*WrappedTx),
-		hashTxs:   make(map[[mempool.TxKeySize]byte]*WrappedTx),
+		hashTxs:   make(map[types.TxKey]*WrappedTx),
 	}
 }
 
@@ -110,7 +109,7 @@ func (txs *TxStore) GetTxBySender(sender string) *WrappedTx {
 }
 
 // GetTxByHash returns a *WrappedTx by the transaction's hash.
-func (txs *TxStore) GetTxByHash(hash [mempool.TxKeySize]byte) *WrappedTx {
+func (txs *TxStore) GetTxByHash(hash types.TxKey) *WrappedTx {
 	txs.mtx.RLock()
 	defer txs.mtx.RUnlock()
 
@@ -119,7 +118,7 @@ func (txs *TxStore) GetTxByHash(hash [mempool.TxKeySize]byte) *WrappedTx {
 
 // IsTxRemoved returns true if a transaction by hash is marked as removed and
 // false otherwise.
-func (txs *TxStore) IsTxRemoved(hash [mempool.TxKeySize]byte) bool {
+func (txs *TxStore) IsTxRemoved(hash types.TxKey) bool {
 	txs.mtx.RLock()
 	defer txs.mtx.RUnlock()
 
@@ -142,7 +141,7 @@ func (txs *TxStore) SetTx(wtx *WrappedTx) {
 		txs.senderTxs[wtx.sender] = wtx
 	}
 
-	txs.hashTxs[mempool.TxKey(wtx.tx)] = wtx
+	txs.hashTxs[wtx.tx.Key()] = wtx
 }
 
 // RemoveTx removes a *WrappedTx from the transaction store. It deletes all
@@ -155,13 +154,13 @@ func (txs *TxStore) RemoveTx(wtx *WrappedTx) {
 		delete(txs.senderTxs, wtx.sender)
 	}
 
-	delete(txs.hashTxs, mempool.TxKey(wtx.tx))
+	delete(txs.hashTxs, wtx.tx.Key())
 	wtx.removed = true
 }
 
 // TxHasPeer returns true if a transaction by hash has a given peer ID and false
 // otherwise. If the transaction does not exist, false is returned.
-func (txs *TxStore) TxHasPeer(hash [mempool.TxKeySize]byte, peerID uint16) bool {
+func (txs *TxStore) TxHasPeer(hash types.TxKey, peerID uint16) bool {
 	txs.mtx.RLock()
 	defer txs.mtx.RUnlock()
 
@@ -179,7 +178,7 @@ func (txs *TxStore) TxHasPeer(hash [mempool.TxKeySize]byte, peerID uint16) bool
 // We return true if we've already recorded the given peer for this transaction
 // and false otherwise. If the transaction does not exist by hash, we return
 // (nil, false).
-func (txs *TxStore) GetOrSetPeerByTxHash(hash [mempool.TxKeySize]byte, peerID uint16) (*WrappedTx, bool) {
+func (txs *TxStore) GetOrSetPeerByTxHash(hash types.TxKey, peerID uint16) (*WrappedTx, bool) {
 	txs.mtx.Lock()
 	defer txs.mtx.Unlock()
 

internal/mempool/v1/tx_test.go

@@ -8,7 +8,7 @@ import (
 	"time"
 
 	"github.com/stretchr/testify/require"
-	"github.com/tendermint/tendermint/internal/mempool"
+	"github.com/tendermint/tendermint/types"
 )
 
 func TestTxStore_GetTxBySender(t *testing.T) {
@@ -39,7 +39,7 @@ func TestTxStore_GetTxByHash(t *testing.T) {
 		timestamp: time.Now(),
 	}
 
-	key := mempool.TxKey(wtx.tx)
+	key := wtx.tx.Key()
 	res := txs.GetTxByHash(key)
 	require.Nil(t, res)
 
@@ -58,7 +58,7 @@ func TestTxStore_SetTx(t *testing.T) {
 		timestamp: time.Now(),
 	}
 
-	key := mempool.TxKey(wtx.tx)
+	key := wtx.tx.Key()
 	txs.SetTx(wtx)
 
 	res := txs.GetTxByHash(key)
@@ -81,10 +81,10 @@ func TestTxStore_GetOrSetPeerByTxHash(t *testing.T) {
 		timestamp: time.Now(),
 	}
 
-	key := mempool.TxKey(wtx.tx)
+	key := wtx.tx.Key()
 	txs.SetTx(wtx)
 
-	res, ok := txs.GetOrSetPeerByTxHash(mempool.TxKey([]byte("test_tx_2")), 15)
+	res, ok := txs.GetOrSetPeerByTxHash(types.Tx([]byte("test_tx_2")).Key(), 15)
 	require.Nil(t, res)
 	require.False(t, ok)
 
@@ -110,7 +110,7 @@ func TestTxStore_RemoveTx(t *testing.T) {
 
 	txs.SetTx(wtx)
 
-	key := mempool.TxKey(wtx.tx)
+	key := wtx.tx.Key()
 	res := txs.GetTxByHash(key)
 	require.NotNil(t, res)
 

internal/rpc/core/mempool.go

@@ -151,3 +151,7 @@ func (env *Environment) CheckTx(ctx *rpctypes.Context, tx types.Tx) (*coretypes.
 	}
 	return &coretypes.ResultCheckTx{ResponseCheckTx: *res}, nil
 }
+
+func (env *Environment) RemoveTx(ctx *rpctypes.Context, txkey types.TxKey) error {
+	return env.Mempool.RemoveTxByKey(txkey)
+}

internal/rpc/core/routes.go

@@ -28,6 +28,7 @@ func (env *Environment) GetRoutes() RoutesMap {
 		"block_results":        rpc.NewRPCFunc(env.BlockResults, "height", true),
 		"commit":               rpc.NewRPCFunc(env.Commit, "height", true),
 		"check_tx":             rpc.NewRPCFunc(env.CheckTx, "tx", true),
+		"remove_tx":            rpc.NewRPCFunc(env.RemoveTx, "txkey", false),
 		"tx":                   rpc.NewRPCFunc(env.Tx, "hash,prove", true),
 		"tx_search":            rpc.NewRPCFunc(env.TxSearch, "query,prove,page,per_page,order_by", false),
 		"block_search":         rpc.NewRPCFunc(env.BlockSearch, "query,page,per_page,order_by", false),

light/rpc/client.go

@@ -212,6 +212,10 @@ func (c *Client) CheckTx(ctx context.Context, tx types.Tx) (*coretypes.ResultChe
 	return c.next.CheckTx(ctx, tx)
 }
 
+func (c *Client) RemoveTx(ctx context.Context, txKey types.TxKey) error {
+	return c.next.RemoveTx(ctx, txKey)
+}
+
 func (c *Client) NetInfo(ctx context.Context) (*coretypes.ResultNetInfo, error) {
 	return c.next.NetInfo(ctx)
 }

rpc/client/http/http.go

@@ -315,6 +315,14 @@ func (c *baseRPCClient) CheckTx(ctx context.Context, tx types.Tx) (*coretypes.Re
 	return result, nil
 }
 
+func (c *baseRPCClient) RemoveTx(ctx context.Context, txKey types.TxKey) error {
+	_, err := c.caller.Call(ctx, "remove_tx", map[string]interface{}{"tx_key": txKey}, nil)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
 func (c *baseRPCClient) NetInfo(ctx context.Context) (*coretypes.ResultNetInfo, error) {
 	result := new(coretypes.ResultNetInfo)
 	_, err := c.caller.Call(ctx, "net_info", map[string]interface{}{}, result)

rpc/client/interface.go

@@ -146,6 +146,7 @@ type MempoolClient interface {
 	UnconfirmedTxs(ctx context.Context, limit *int) (*coretypes.ResultUnconfirmedTxs, error)
 	NumUnconfirmedTxs(context.Context) (*coretypes.ResultUnconfirmedTxs, error)
 	CheckTx(context.Context, types.Tx) (*coretypes.ResultCheckTx, error)
+	RemoveTx(context.Context, types.TxKey) error
 }
 
 // EvidenceClient is used for submitting an evidence of the malicious

rpc/client/local/local.go

@@ -116,6 +116,10 @@ func (c *Local) CheckTx(ctx context.Context, tx types.Tx) (*coretypes.ResultChec
 	return c.env.CheckTx(c.ctx, tx)
 }
 
+func (c *Local) RemoveTx(ctx context.Context, txKey types.TxKey) error {
+	return c.env.Mempool.RemoveTxByKey(txKey)
+}
+
 func (c *Local) NetInfo(ctx context.Context) (*coretypes.ResultNetInfo, error) {
 	return c.env.NetInfo(c.ctx)
 }

rpc/openapi/openapi.yaml

@@ -237,6 +237,31 @@ paths:
             application/json:
               schema:
                 $ref: "#/components/schemas/ErrorResponse"
+
+  /remove_tx:
+    get:
+      summary: Removes a transaction from the mempool.
+      tags:
+        - TxKey
+      operationId: remove_tx
+      parameters:
+        - in: query
+          name: txKey
+          required: true
+          schema:
+            type: string
+            example: "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+          description: The transaction key
+      responses:
+        "200":
+          description: empty response.
+        "500":
+          description: empty error.
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/ErrorResponse"
+
   /subscribe:
     get:
       summary: Subscribe for events via WebSocket.

types/mempool.go

@@ -1,14 +1,16 @@
 package types
 
 import (
+	"crypto/sha256"
 	"errors"
 	"fmt"
 )
 
-var (
-	// ErrTxInCache is returned to the client if we saw tx earlier
-	ErrTxInCache = errors.New("tx already exists in cache")
-)
+// ErrTxInCache is returned to the client if we saw tx earlier
+var ErrTxInCache = errors.New("tx already exists in cache")
+
+// TxKey is the fixed length array key used as an index.
+type TxKey [sha256.Size]byte
 
 // ErrTxTooLarge defines an error when a transaction is too big to be sent in a
 // message to other peers.

types/tx.go

@@ -2,6 +2,7 @@ package types
 
 import (
 	"bytes"
+	"crypto/sha256"
 	"errors"
 	"fmt"
 
@@ -16,15 +17,14 @@ import (
 // Might we want types here ?
 type Tx []byte
 
+// Key produces a fixed-length key for use in indexing.
+func (tx Tx) Key() TxKey { return sha256.Sum256(tx) }
+
 // Hash computes the TMHASH hash of the wire encoded transaction.
-func (tx Tx) Hash() []byte {
-	return tmhash.Sum(tx)
-}
+func (tx Tx) Hash() []byte { return tmhash.Sum(tx) }
 
 // String returns the hex-encoded transaction as a string.
-func (tx Tx) String() string {
-	return fmt.Sprintf("Tx{%X}", []byte(tx))
-}
+func (tx Tx) String() string { return fmt.Sprintf("Tx{%X}", []byte(tx)) }
 
 // Txs is a slice of Tx.
 type Txs []Tx