cache stx id

data/transactions/signedtxn.go

@@ -37,6 +37,8 @@ type SignedTxn struct {
 	Lsig     LogicSig           `codec:"lsig"`
 	Txn      Transaction        `codec:"txn"`
 	AuthAddr basics.Address     `codec:"sgnr"`
+
+	cachedID *Txid
 }
 
 // SignedTxnInBlock is how a signed transaction is encoded in a block.
@@ -59,9 +61,17 @@ type SignedTxnWithAD struct {
 
 // ID returns the Txid (i.e., hash) of the underlying transaction.
 func (s SignedTxn) ID() Txid {
+	if s.cachedID != nil {
+		return *s.cachedID
+	}
 	return s.Txn.ID()
 }
 
+func (s *SignedTxn) CacheID() {
+	txid := s.Txn.ID()
+	s.cachedID = &txid
+}
+
 // ID on SignedTxnInBlock should never be called, because the ID depends
 // on the block from which this transaction will be decoded.  By having
 // a different return value from SignedTxn.ID(), we will catch errors at

data/txHandler.go

@@ -531,6 +531,11 @@ func (handler *TxHandler) postProcessCheckedTxn(wi *txBacklogMsg) {
 	// at this point, we've verified the transaction, so we can safely treat the transaction as a verified transaction.
 	verifiedTxGroup := wi.unverifiedTxGroup
 
+	// precompute transaction IDs
+	for i := range verifiedTxGroup {
+		verifiedTxGroup[i].CacheID()
+	}
+
 	// save the transaction, if it has high enough fee and not already in the cache
 	err := handler.txPool.Remember(verifiedTxGroup)
 	if err != nil {