From c93034f2902b3d74ced5359267cbe11b569dd47c Mon Sep 17 00:00:00 2001
From: Lee Bousfield <ljbousfield@gmail.com>
Date: Wed, 31 Aug 2022 15:53:48 -0500
Subject: [PATCH] Make sequencer pending tx queue size configurable

---
 arbnode/node.go      | 4 ++++
 arbnode/sequencer.go | 4 ++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/arbnode/node.go b/arbnode/node.go
index 71fe8fd866..2093dc290a 100644
--- a/arbnode/node.go
+++ b/arbnode/node.go
@@ -537,6 +537,7 @@ type SequencerConfig struct {
 	MaxAcceptableTimestampDelta time.Duration            `koanf:"max-acceptable-timestamp-delta"`
 	SenderWhitelist             string                   `koanf:"sender-whitelist"`
 	ForwardTimeout              time.Duration            `koanf:"forward-timeout"`
+	QueueSize                   int                      `koanf:"queue-size"`
 	Dangerous                   DangerousSequencerConfig `koanf:"dangerous"`
 }
 
@@ -548,6 +549,7 @@ var DefaultSequencerConfig = SequencerConfig{
 	MaxRevertGasReject:          params.TxGas + 10000,
 	MaxAcceptableTimestampDelta: time.Hour,
 	ForwardTimeout:              time.Second * 30,
+	QueueSize:                   1024,
 	Dangerous:                   DefaultDangerousSequencerConfig,
 }
 
@@ -558,6 +560,7 @@ var TestSequencerConfig = SequencerConfig{
 	MaxAcceptableTimestampDelta: time.Hour,
 	SenderWhitelist:             "",
 	ForwardTimeout:              time.Second * 2,
+	QueueSize:                   128,
 	Dangerous:                   TestDangerousSequencerConfig,
 }
 
@@ -568,6 +571,7 @@ func SequencerConfigAddOptions(prefix string, f *flag.FlagSet) {
 	f.Duration(prefix+".max-acceptable-timestamp-delta", DefaultSequencerConfig.MaxAcceptableTimestampDelta, "maximum acceptable time difference between the local time and the latest L1 block's timestamp")
 	f.String(prefix+".sender-whitelist", DefaultSequencerConfig.SenderWhitelist, "comma separated whitelist of authorized senders (if empty, everyone is allowed)")
 	f.Duration(prefix+".forward-timeout", DefaultSequencerConfig.ForwardTimeout, "timeout when forwarding to a different sequencer")
+	f.Int(prefix+".queue-size", DefaultSequencerConfig.QueueSize, "size of the pending tx queue")
 	DangerousSequencerConfigAddOptions(prefix+".dangerous", f)
 }
 
diff --git a/arbnode/sequencer.go b/arbnode/sequencer.go
index 879cf12453..9f0d95ddc0 100644
--- a/arbnode/sequencer.go
+++ b/arbnode/sequencer.go
@@ -71,7 +71,7 @@ func NewSequencer(txStreamer *TransactionStreamer, l1Reader *headerreader.Header
 	}
 	return &Sequencer{
 		txStreamer:      txStreamer,
-		txQueue:         make(chan txQueueItem, 128),
+		txQueue:         make(chan txQueueItem, config().QueueSize),
 		l1Reader:        l1Reader,
 		config:          config,
 		senderWhitelist: senderWhitelist,
@@ -172,7 +172,7 @@ func (s *Sequencer) DontForward() {
 	s.forwarder = nil
 }
 
-var ErrQueueFull error = errors.New("queue full")
+var ErrQueueFull error = errors.New("sequencer pending tx pool full, please try again")
 var ErrNoSequencer error = errors.New("sequencer temporarily not available")
 
 func (s *Sequencer) requeueOrFail(queueItem txQueueItem, err error) {