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Merged
yashnevatia merged 2 commits into from
Sep 21, 2026
Merged

Add cache size for unknown requests in consensus handler #770

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a1c9a01
Add cache size for unknown requests in consensus handler
yashnevatia Sep 16, 2026
b245848
add log line
yashnevatia Sep 21, 2026
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15 changes: 12 additions & 3 deletions libs/chainconsensus/handler.go
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Original file line number Diff line number Diff line change
Expand Up @@ -50,18 +50,20 @@ type handler struct {
unknownRequestsResultByID map[string]*unknownRequest
unknownRequestsOrderedByTimeout *list.List[*unknownRequest]
unknownRequestTTL time.Duration
maxUnknownRequestsCacheSize int
}

func NewHandler(lggr logger.Logger, poller Poller, metrics metrics.ConsensusMetrics, unknownRequestTTL time.Duration) Handler {
return newHandler(lggr, poller, metrics, unknownRequestTTL)
func NewHandler(lggr logger.Logger, poller Poller, metrics metrics.ConsensusMetrics, unknownRequestTTL time.Duration, maxUnknownRequestsCacheSize int) Handler {
return newHandler(lggr, poller, metrics, unknownRequestTTL, maxUnknownRequestsCacheSize)
}

func newHandler(lggr logger.Logger, poller Poller, metrics metrics.ConsensusMetrics, unknownRequestTTL time.Duration) *handler {
func newHandler(lggr logger.Logger, poller Poller, metrics metrics.ConsensusMetrics, unknownRequestTTL time.Duration, maxUnknownRequestsCacheSize int) *handler {
r := &handler{
requests: requests.NewStoreWithStatsCollector[*requestCtx](metrics),
unknownRequestsResultByID: make(map[string]*unknownRequest),
unknownRequestsOrderedByTimeout: list.New[*unknownRequest](),
unknownRequestTTL: unknownRequestTTL,
maxUnknownRequestsCacheSize: maxUnknownRequestsCacheSize,
poller: poller,
metrics: metrics,
}
Expand Down Expand Up @@ -210,6 +212,13 @@ func (s *handler) completeRequest(id string, reply types.Reply) error {
defer s.lock.Unlock()
request := s.requests.Get(id)
if request == nil {
if s.maxUnknownRequestsCacheSize > 0 && len(s.unknownRequestsResultByID) >= s.maxUnknownRequestsCacheSize {
s.lggr.Warnf("unknown requests cache is full, evicting oldest request")
if oldest := s.unknownRequestsOrderedByTimeout.Front(); oldest != nil {

@dhaidashenko dhaidashenko Sep 17, 2026

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It would be nice to have visibility into the size of the unknown requests cache.
I'm ok with logging on evictiond due to overflow or a metric

@yashnevatia yashnevatia Sep 21, 2026

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added log line

delete(s.unknownRequestsResultByID, oldest.Value.ID)
s.unknownRequestsOrderedByTimeout.Remove(oldest)
}
}
uRequest := &unknownRequest{
ID: id,
ExpiresAt: time.Now().Add(s.unknownRequestTTL),
Expand Down
39 changes: 35 additions & 4 deletions libs/chainconsensus/handler_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ import (
func TestGetRequestIDs(t *testing.T) {
poller := mocks.NewPoller(t)
poller.EXPECT().Enqueue(mock.Anything, mock.Anything)
handler := NewHandler(logger.Test(t), poller, test.GetConsensusMetrics(t), time.Second)
handler := NewHandler(logger.Test(t), poller, test.GetConsensusMetrics(t), time.Second, 1000)
addRequestToHandler := func(t *testing.T, ctx context.Context, id string) {
request := types.NewEventuallyConsistentRequest(id, nil)
_, err := handler.Handle(ctx, request)
Expand Down Expand Up @@ -72,7 +72,7 @@ func TestGetRequestIDs(t *testing.T) {
func TestGetRequest(t *testing.T) {
poller := mocks.NewPoller(t)
poller.EXPECT().Enqueue(mock.Anything, mock.Anything).Maybe()
handler := NewHandler(logger.Test(t), poller, test.GetConsensusMetrics(t), time.Second)
handler := NewHandler(logger.Test(t), poller, test.GetConsensusMetrics(t), time.Second, 1000)
addRequestToHandler := func(t *testing.T, ctx context.Context, id string) {
request := types.NewAggregatableRequest(id, nil)
_, err := handler.Handle(ctx, request)
Expand Down Expand Up @@ -102,7 +102,7 @@ func TestGetRequest(t *testing.T) {

func TestCompleteRequest(t *testing.T) {
newHandler := func(t *testing.T, lggr logger.Logger, poller Poller) *handler {
h := newHandler(lggr, poller, test.GetConsensusMetrics(t), time.Second)
h := newHandler(lggr, poller, test.GetConsensusMetrics(t), time.Second, 1000)
require.NoError(t, h.Start(t.Context()))
t.Cleanup(func() {
require.NoError(t, h.Close())
Expand Down Expand Up @@ -276,7 +276,7 @@ func TestCompleteRequest(t *testing.T) {

func TestHandle(t *testing.T) {
poller := mocks.NewPoller(t)
handler := NewHandler(logger.Test(t), poller, test.GetConsensusMetrics(t), time.Second)
handler := NewHandler(logger.Test(t), poller, test.GetConsensusMetrics(t), time.Second, 1000)
require.NoError(t, handler.Start(t.Context()))
t.Cleanup(func() {
require.NoError(t, handler.Close())
Expand Down Expand Up @@ -309,3 +309,34 @@ func mustMarshalProto(t *testing.T, msg proto.Message) []byte {
require.NoError(t, err)
return data
}

func TestCompleteRequest_UnknownRequestsCacheEviction(t *testing.T) {
const maxCacheSize = 3
h := newHandler(logger.Test(t), nil, test.GetConsensusMetrics(t), time.Minute, maxCacheSize)

completeUnknown := func(t *testing.T, id string) {
require.NoError(t, h.CompleteProtoRequest(id, &types.RequestReport{
Report: &types.RequestReport_EventuallyConsistent{EventuallyConsistent: []byte(id)},
}))
}

completeUnknown(t, "req-1")
completeUnknown(t, "req-2")
completeUnknown(t, "req-3")

h.lock.RLock()
require.Len(t, h.unknownRequestsResultByID, maxCacheSize)
require.Contains(t, h.unknownRequestsResultByID, "req-1")
h.lock.RUnlock()

// cache is full; completing one more unknown request must evict the oldest ("req-1")
completeUnknown(t, "req-4")

h.lock.RLock()
require.Len(t, h.unknownRequestsResultByID, maxCacheSize)
require.NotContains(t, h.unknownRequestsResultByID, "req-1")
require.Contains(t, h.unknownRequestsResultByID, "req-2")
require.Contains(t, h.unknownRequestsResultByID, "req-3")
require.Contains(t, h.unknownRequestsResultByID, "req-4")
h.lock.RUnlock()
}
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