Update committee cache size to 32 (#7018)

* Update committee cache size to 32
* Merge branch 'master' into update-committee-cache-size
* Cache: fixed rotating test
* Merge branch 'update-committee-cache-size' of github.com:prysmaticlabs/prysm into update-committee-cache-size
* Merge refs/heads/master into update-committee-cache-size
* Merge refs/heads/master into update-committee-cache-size
* Merge refs/heads/master into update-committee-cache-size

beacon-chain/cache/committee.go

@@ -17,9 +17,8 @@ var (
 	ErrNotCommittee = errors.New("object is not a committee struct")
 
 	// maxCommitteesCacheSize defines the max number of shuffled committees on per randao basis can cache.
-	// Due to reorgs, it's good to keep the old cache around for quickly switch over. 10 is a generous
-	// cache size as it considers 3 concurrent branches over 3 epochs.
-	maxCommitteesCacheSize = uint64(10)
+	// Due to reorgs and long finality, it's good to keep the old cache around for quickly switch over.
+	maxCommitteesCacheSize = uint64(32)
 
 	// CommitteeCacheMiss tracks the number of committee requests that aren't present in the cache.
 	CommitteeCacheMiss = promauto.NewCounter(prometheus.CounterOpts{

beacon-chain/cache/committee_test.go

@@ -122,7 +122,9 @@ func TestCommitteeCache_CanRotate(t *testing.T) {
 	cache := NewCommitteesCache()
 
 	// Should rotate out all the epochs except 190 through 199.
-	for i := 100; i < 200; i++ {
+	start := 100
+	end := 200
+	for i := start; i < end; i++ {
 		s := []byte(strconv.Itoa(i))
 		item := &Committees{Seed: bytesutil.ToBytes32(s)}
 		require.NoError(t, cache.AddCommitteeShuffledList(item))
@@ -134,7 +136,8 @@ func TestCommitteeCache_CanRotate(t *testing.T) {
 	sort.Slice(k, func(i, j int) bool {
 		return k[i] < k[j]
 	})
-	s := bytesutil.ToBytes32([]byte(strconv.Itoa(190)))
+	wanted := end - int(maxCommitteesCacheSize)
+	s := bytesutil.ToBytes32([]byte(strconv.Itoa(wanted)))
 	assert.Equal(t, key(s), k[0], "incorrect key received for slot 190")
 
 	s = bytesutil.ToBytes32([]byte(strconv.Itoa(199)))