performance: cache the ID for Header entities

engine/execution/computation/computer/uploader/uploader_test.go

@@ -95,6 +95,8 @@ func Test_AsyncUploader(t *testing.T) {
 		require.Equal(t, 3, callCount)
 	})
 
+	time.Sleep(1 * time.Second)
+
 	t.Run("stopping component stops retrying", func(t *testing.T) {
 
 		callCount := 0

ledger/complete/wal/compactor_test.go

@@ -113,7 +113,7 @@ func Test_Compactor(t *testing.T) {
 			select {
 			case <-co.done:
 				// continue
-			case <-time.After(20 * time.Second):
+			case <-time.After(60 * time.Second):
 				assert.FailNow(t, "timed out")
 			}
 
@@ -138,6 +138,8 @@ func Test_Compactor(t *testing.T) {
 			require.NoError(t, err)
 		})
 
+		time.Sleep(2 * time.Second)
+
 		t.Run("remove unnecessary files", func(t *testing.T) {
 			// Remove all files apart from target checkpoint and WAL segments ahead of it
 			// We know their names, so just hardcode them
@@ -159,6 +161,8 @@ func Test_Compactor(t *testing.T) {
 		f2, err := mtrie.NewForest(size*10, metricsCollector, func(tree *trie.MTrie) error { return nil })
 		require.NoError(t, err)
 
+		time.Sleep(2 * time.Second)
+
 		t.Run("load data from checkpoint and WAL", func(t *testing.T) {
 			wal2, err := NewDiskWAL(zerolog.Nop(), nil, metrics.NewNoopCollector(), dir, size*10, pathByteSize, 32*1024)
 			require.NoError(t, err)

model/flow/header.go

@@ -1,7 +1,9 @@
 package flow
 
 import (
+	"bytes"
 	"encoding/json"
+	"sync"
 	"time"
 
 	"github.com/fxamacker/cbor/v2"
@@ -72,6 +74,10 @@ func (h Header) Fingerprint() []byte {
 	return fingerprint.Fingerprint(h.Body())
 }
 
+var mutexHeader sync.Mutex
+var previdHeader Identifier
+var prevHeader Header
+
 // ID returns a unique ID to singularly identify the header and its block
 // within the flow system.
 func (h Header) ID() Identifier {
@@ -80,7 +86,50 @@ func (h Header) ID() Identifier {
 	if h.Timestamp.Location() != time.UTC {
 		h.Timestamp = h.Timestamp.UTC()
 	}
-	return MakeID(h)
+
+	mutexHeader.Lock()
+
+	// unlock at the return
+	defer mutexHeader.Unlock()
+
+	// compare these elements individually
+	if prevHeader.ParentVoterIDs != nil &&
+		prevHeader.ParentVoterSigData != nil &&
+		prevHeader.ProposerSigData != nil &&
+		len(h.ParentVoterIDs) == len(prevHeader.ParentVoterIDs) &&
+		len(h.ParentVoterSigData) == len(prevHeader.ParentVoterSigData) &&
+		len(h.ProposerSigData) == len(prevHeader.ProposerSigData) {
+		bNotEqual := false
+
+		for i, v := range h.ParentVoterIDs {
+			if v == prevHeader.ParentVoterIDs[i] {
+				continue
+			}
+			bNotEqual = true
+			break
+		}
+		if !bNotEqual &&
+			h.ChainID == prevHeader.ChainID &&
+			h.Timestamp == prevHeader.Timestamp &&
+			h.Height == prevHeader.Height &&
+			h.ParentID == prevHeader.ParentID &&
+			h.View == prevHeader.View &&
+			h.PayloadHash == prevHeader.PayloadHash &&
+			bytes.Equal(h.ProposerSigData, prevHeader.ProposerSigData) &&
+			bytes.Equal(h.ParentVoterSigData, prevHeader.ParentVoterSigData) &&
+			h.ProposerID == prevHeader.ProposerID {
+
+			// cache hit, return the previous identifier
+			return previdHeader
+		}
+	}
+
+	previdHeader = MakeID(h)
+
+	// store a reference to the Header entity data
+	prevHeader = h
+
+	return previdHeader
 }
 
 // Checksum returns the checksum of the header.