op-batcher: Add metrics for pending L2 transaction data size

op-batcher/batcher/channel_manager.go

@@ -228,6 +228,7 @@ func (s *channelManager) processBlocks() error {
 		}
 		blocksAdded += 1
 		latestL2ref = l2BlockRefFromBlockAndL1Info(block, l1info)
+		s.metr.RecordL2BlockInChannel(block)
 		// current block got added but channel is now full
 		if s.currentChannel.IsFull() {
 			break
@@ -298,6 +299,8 @@ func (s *channelManager) AddL2Block(block *types.Block) error {
 	if s.tip != (common.Hash{}) && s.tip != block.ParentHash() {
 		return ErrReorg
 	}
+
+	s.metr.RecordL2BlockInPendingQueue(block)
 	s.blocks = append(s.blocks, block)
 	s.tip = block.Hash()
 

op-batcher/metrics/metrics.go

@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/ethclient"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/prometheus/client_golang/prometheus"
@@ -30,6 +31,8 @@ type Metricer interface {
 	RecordL2BlocksLoaded(l2ref eth.L2BlockRef)
 	RecordChannelOpened(id derive.ChannelID, numPendingBlocks int)
 	RecordL2BlocksAdded(l2ref eth.L2BlockRef, numBlocksAdded, numPendingBlocks, inputBytes, outputComprBytes int)
+	RecordL2BlockInPendingQueue(block *types.Block)
+	RecordL2BlockInChannel(block *types.Block)
 	RecordChannelClosed(id derive.ChannelID, numPendingBlocks int, numFrames int, inputBytes int, outputComprBytes int, reason error)
 	RecordChannelFullySubmitted(id derive.ChannelID)
 	RecordChannelTimedOut(id derive.ChannelID)
@@ -56,6 +59,8 @@ type Metrics struct {
 	channelEvs opmetrics.EventVec
 
 	pendingBlocksCount        prometheus.GaugeVec
+	pendingBlocksBytesTotal   prometheus.Counter
+	pendingBlocksBytesCurrent prometheus.Gauge
 	blocksAddedCount          prometheus.Gauge
 
 	channelInputBytes       prometheus.GaugeVec
@@ -109,6 +114,16 @@ func NewMetrics(procName string) *Metrics {
 			Name:      "pending_blocks_count",
 			Help:      "Number of pending blocks, not added to a channel yet.",
 		}, []string{"stage"}),
+		pendingBlocksBytesTotal: factory.NewCounter(prometheus.CounterOpts{
+			Namespace: ns,
+			Name:      "pending_blocks_bytes_total",
+			Help:      "Total size of transactions in pending blocks as they are fetched from L2",
+		}),
+		pendingBlocksBytesCurrent: factory.NewGauge(prometheus.GaugeOpts{
+			Namespace: ns,
+			Name:      "pending_blocks_bytes_current",
+			Help:      "Current size of transactions in the pending (fetched from L2 but not in a channel) stage.",
+		}),
 		blocksAddedCount: factory.NewGauge(prometheus.GaugeOpts{
 			Namespace: ns,
 			Name:      "blocks_added_count",
@@ -243,6 +258,18 @@ func (m *Metrics) RecordChannelClosed(id derive.ChannelID, numPendingBlocks int,
 	m.channelClosedReason.Set(float64(ClosedReasonToNum(reason)))
 }
 
+func (m *Metrics) RecordL2BlockInPendingQueue(block *types.Block) {
+	size := float64(estimateBatchSize(block))
+	m.pendingBlocksBytesTotal.Add(size)
+	m.pendingBlocksBytesCurrent.Add(size)
+}
+
+func (m *Metrics) RecordL2BlockInChannel(block *types.Block) {
+	size := float64(estimateBatchSize(block))
+	m.pendingBlocksBytesCurrent.Add(-1 * size)
+	// Refer to RecordL2BlocksAdded to see the current + count of bytes added to a channel
+}
+
 func ClosedReasonToNum(reason error) int {
 	// CLI-3640
 	return 0
@@ -267,3 +294,17 @@ func (m *Metrics) RecordBatchTxSuccess() {
 func (m *Metrics) RecordBatchTxFailed() {
 	m.batcherTxEvs.Record(TxStageFailed)
 }
+
+// estimateBatchSize estimates the size of the batch
+func estimateBatchSize(block *types.Block) uint64 {
+	size := uint64(70) // estimated overhead of batch metadata
+	for _, tx := range block.Transactions() {
+		// Don't include deposit transactions in the batch.
+		if tx.IsDepositTx() {
+			continue
+		}
+		// Add 2 for the overhead of encoding the tx bytes in a RLP list
+		size += tx.Size() + 2
+	}
+	return size
+}

op-batcher/metrics/noop.go

@@ -5,6 +5,7 @@ import (
 	"github.com/ethereum-optimism/optimism/op-node/rollup/derive"
 	opmetrics "github.com/ethereum-optimism/optimism/op-service/metrics"
 	txmetrics "github.com/ethereum-optimism/optimism/op-service/txmgr/metrics"
+	"github.com/ethereum/go-ethereum/core/types"
 )
 
 type noopMetrics struct {
@@ -23,6 +24,8 @@ func (*noopMetrics) RecordLatestL1Block(l1ref eth.L1BlockRef)               {}
 func (*noopMetrics) RecordL2BlocksLoaded(eth.L2BlockRef)                    {}
 func (*noopMetrics) RecordChannelOpened(derive.ChannelID, int)              {}
 func (*noopMetrics) RecordL2BlocksAdded(eth.L2BlockRef, int, int, int, int) {}
+func (*noopMetrics) RecordL2BlockInPendingQueue(*types.Block)               {}
+func (*noopMetrics) RecordL2BlockInChannel(*types.Block)                    {}
 
 func (*noopMetrics) RecordChannelClosed(derive.ChannelID, int, int, int, int, error) {}