Fix after review, drop logic around fnv32.

txcache/README.md

@@ -93,7 +93,7 @@ That is, for contract calls, the PPU is not equal to the gas price, but much low
 
 Transaction **A** is considered **more valuable (for the Network)** than transaction **B** if **it has a higher PPU**.
 
-If two transactions have the same PPU, they are ordered using an arbitrary, but deterministic rule: the transaction with the higher [fnv32(transactionHash)](https://en.wikipedia.org/wiki/Fowler%E2%80%93Noll%E2%80%93Vo_hash_function) "wins" the comparison.
+If two transactions have the same PPU, they are ordered using an arbitrary, but deterministic rule: the transaction with the "lower" transaction hash "wins" the comparison.
 
 Pseudo-code:
 
@@ -103,7 +103,7 @@ func isTransactionMoreValuableForNetwork(A, B):
         return true
     if A.ppu < B.ppu:
         return false
-    return fnv32(A.hash) > fnv32(B.hash)
+    return A.hash < B.hash
 ```
 
 ### Paragraph 4

txcache/selection_test.go

@@ -15,28 +15,13 @@ func TestTxCache_SelectTransactions_Dummy(t *testing.T) {
 		cache := newUnconstrainedCacheToTest()
 
 		cache.AddTx(createTx([]byte("hash-alice-4"), "alice", 4))
-		require.Equal(t, 3193030061, int(fnv32("hash-alice-4")))
-
 		cache.AddTx(createTx([]byte("hash-alice-3"), "alice", 3))
-		require.Equal(t, 3193030058, int(fnv32("hash-alice-3")))
-
 		cache.AddTx(createTx([]byte("hash-alice-2"), "alice", 2))
-		require.Equal(t, 3193030059, int(fnv32("hash-alice-2")))
-
 		cache.AddTx(createTx([]byte("hash-alice-1"), "alice", 1))
-		require.Equal(t, 3193030056, int(fnv32("hash-alice-1")))
-
 		cache.AddTx(createTx([]byte("hash-bob-7"), "bob", 7))
-		require.Equal(t, 187766579, int(fnv32("hash-bob-7")))
-
 		cache.AddTx(createTx([]byte("hash-bob-6"), "bob", 6))
-		require.Equal(t, 187766578, int(fnv32("hash-bob-6")))
-
 		cache.AddTx(createTx([]byte("hash-bob-5"), "bob", 5))
-		require.Equal(t, 187766577, int(fnv32("hash-bob-5")))
-
 		cache.AddTx(createTx([]byte("hash-carol-1"), "carol", 1))
-		require.Equal(t, 3082288595, int(fnv32("hash-carol-1")))
 
 		selected, accumulatedGas := cache.SelectTransactions(math.MaxUint64, math.MaxInt)
 		require.Len(t, selected, 8)
@@ -47,10 +32,10 @@ func TestTxCache_SelectTransactions_Dummy(t *testing.T) {
 		require.Equal(t, "hash-alice-2", string(selected[1].TxHash))
 		require.Equal(t, "hash-alice-3", string(selected[2].TxHash))
 		require.Equal(t, "hash-alice-4", string(selected[3].TxHash))
-		require.Equal(t, "hash-carol-1", string(selected[4].TxHash))
-		require.Equal(t, "hash-bob-5", string(selected[5].TxHash))
-		require.Equal(t, "hash-bob-6", string(selected[6].TxHash))
-		require.Equal(t, "hash-bob-7", string(selected[7].TxHash))
+		require.Equal(t, "hash-bob-5", string(selected[4].TxHash))
+		require.Equal(t, "hash-bob-6", string(selected[5].TxHash))
+		require.Equal(t, "hash-bob-7", string(selected[6].TxHash))
+		require.Equal(t, "hash-carol-1", string(selected[7].TxHash))
 	})
 
 	t.Run("alice > carol > bob", func(t *testing.T) {
@@ -89,9 +74,9 @@ func TestTxCache_SelectTransactionsWithBandwidth_Dummy(t *testing.T) {
 		require.Equal(t, 750000, int(accumulatedGas))
 
 		// Check order
-		require.Equal(t, "hash-carol-1", string(selected[0].TxHash))
-		require.Equal(t, "hash-bob-5", string(selected[1].TxHash))
-		require.Equal(t, "hash-bob-6", string(selected[2].TxHash))
+		require.Equal(t, "hash-bob-5", string(selected[0].TxHash))
+		require.Equal(t, "hash-bob-6", string(selected[1].TxHash))
+		require.Equal(t, "hash-carol-1", string(selected[2].TxHash))
 		require.Equal(t, "hash-alice-1", string(selected[3].TxHash))
 		require.Equal(t, "hash-bob-7", string(selected[4].TxHash))
 	})

txcache/wrappedTransaction.go

@@ -1,6 +1,7 @@
 package txcache
 
 import (
+	"bytes"
 	"sync/atomic"
 
 	"github.com/multiversx/mx-chain-core-go/data"
@@ -18,7 +19,6 @@ type WrappedTransaction struct {
 	Size            int64
 
 	PricePerUnit atomic.Uint64
-	HashFnv32    atomic.Uint32
 }
 
 // precomputeFields computes (and caches) the (average) price per gas unit.
@@ -31,18 +31,6 @@ func (wrappedTx *WrappedTransaction) precomputeFields(txGasHandler TxGasHandler)
 	}
 
 	wrappedTx.PricePerUnit.Store(fee / gasLimit)
-	wrappedTx.HashFnv32.Store(fnv32(string(wrappedTx.TxHash)))
-}
-
-// fnv32 implements https://en.wikipedia.org/wiki/Fowler–Noll–Vo_hash_function for 32 bits
-func fnv32(key string) uint32 {
-	hash := uint32(2166136261)
-	const prime32 = uint32(16777619)
-	for i := 0; i < len(key); i++ {
-		hash *= prime32
-		hash ^= uint32(key[i])
-	}
-	return hash
 }
 
 // Equality is out of scope (not possible in our case).
@@ -54,6 +42,6 @@ func (wrappedTx *WrappedTransaction) isTransactionMoreValuableForNetwork(otherTr
 		return ppu > ppuOther
 	}
 
-	// In the end, compare by hash number of transaction hash
-	return wrappedTx.HashFnv32.Load() > otherTransaction.HashFnv32.Load()
+	// In the end, compare by transaction hash
+	return bytes.Compare(wrappedTx.TxHash, otherTransaction.TxHash) < 0
 }

txcache/wrappedTransaction_test.go

@@ -15,15 +15,13 @@ func TestWrappedTransaction_precomputeFields(t *testing.T) {
 		tx.precomputeFields(txGasHandler)
 
 		require.Equal(t, oneBillion, int(tx.PricePerUnit.Load()))
-		require.Equal(t, 84696446, int(tx.HashFnv32.Load()))
 	})
 
 	t.Run("move balance gas limit and execution gas limit (1)", func(t *testing.T) {
 		tx := createTx([]byte("b"), "b", 1).withDataLength(1).withGasLimit(51501).withGasPrice(oneBillion)
 		tx.precomputeFields(txGasHandler)
 
 		require.Equal(t, 999_980_777, int(tx.PricePerUnit.Load()))
-		require.Equal(t, 84696445, int(tx.HashFnv32.Load()))
 	})
 
 	t.Run("move balance gas limit and execution gas limit (2)", func(t *testing.T) {
@@ -32,9 +30,7 @@ func TestWrappedTransaction_precomputeFields(t *testing.T) {
 
 		actualFee := 51500*oneBillion + (oneMilion-51500)*oneBillion/100
 		require.Equal(t, 60_985_000_000_000, actualFee)
-
 		require.Equal(t, actualFee/oneMilion, int(tx.PricePerUnit.Load()))
-		require.Equal(t, 84696444, int(tx.HashFnv32.Load()))
 	})
 }
 
@@ -54,11 +50,9 @@ func TestWrappedTransaction_isTransactionMoreValuableForNetwork(t *testing.T) {
 	t.Run("decide by transaction hash (set them up to have the same PPU)", func(t *testing.T) {
 		a := createTx([]byte("a-7"), "a", 7)
 		a.precomputeFields(txGasHandler)
-		require.Equal(t, 2191299170, int(a.HashFnv32.Load()))
 
 		b := createTx([]byte("b-7"), "b", 7)
 		b.precomputeFields(txGasHandler)
-		require.Equal(t, 1654268265, int(b.HashFnv32.Load()))
 
 		require.True(t, a.isTransactionMoreValuableForNetwork(b))
 	})