eth/gasprice: feeHistory improvements (#23422)

* eth/gasprice: cache feeHistory results

* eth/gasprice: changed feeHistory block count limitation

* eth/gasprice: do not use embedded struct in blockFees

* eth/gasprice: fee processing logic cleanup

* eth/gasprice: purge feeHistory cache at chain reorgs

Author: zsfelfoldi

eth/ethconfig/config.go

@@ -43,8 +43,8 @@ import (
 var FullNodeGPO = gasprice.Config{
 	Blocks:           20,
 	Percentile:       60,
-	MaxHeaderHistory: 0,
-	MaxBlockHistory:  0,
+	MaxHeaderHistory: 1024,
+	MaxBlockHistory:  1024,
 	MaxPrice:         gasprice.DefaultMaxPrice,
 	IgnorePrice:      gasprice.DefaultIgnorePrice,
 }

eth/gasprice/feehistory.go

@@ -18,8 +18,10 @@ package gasprice
 
 import (
 	"context"
+	"encoding/binary"
 	"errors"
 	"fmt"
+	"math"
 	"math/big"
 	"sort"
 	"sync/atomic"
@@ -37,10 +39,6 @@ var (
 )
 
 const (
-	// maxFeeHistory is the maximum number of blocks that can be retrieved for a
-	// fee history request.
-	maxFeeHistory = 1024
-
 	// maxBlockFetchers is the max number of goroutines to spin up to pull blocks
 	// for the fee history calculation (mostly relevant for LES).
 	maxBlockFetchers = 4
@@ -54,10 +52,15 @@ type blockFees struct {
 	block       *types.Block // only set if reward percentiles are requested
 	receipts    types.Receipts
 	// filled by processBlock
+	results processedFees
+	err     error
+}
+
+// processedFees contains the results of a processed block and is also used for caching
+type processedFees struct {
 	reward               []*big.Int
 	baseFee, nextBaseFee *big.Int
 	gasUsedRatio         float64
-	err                  error
 }
 
 // txGasAndReward is sorted in ascending order based on reward
@@ -82,15 +85,15 @@ func (s sortGasAndReward) Less(i, j int) bool {
 // fills in the rest of the fields.
 func (oracle *Oracle) processBlock(bf *blockFees, percentiles []float64) {
 	chainconfig := oracle.backend.ChainConfig()
-	if bf.baseFee = bf.header.BaseFee; bf.baseFee == nil {
-		bf.baseFee = new(big.Int)
+	if bf.results.baseFee = bf.header.BaseFee; bf.results.baseFee == nil {
+		bf.results.baseFee = new(big.Int)
 	}
 	if chainconfig.IsLondon(big.NewInt(int64(bf.blockNumber + 1))) {
-		bf.nextBaseFee = misc.CalcBaseFee(chainconfig, bf.header)
+		bf.results.nextBaseFee = misc.CalcBaseFee(chainconfig, bf.header)
 	} else {
-		bf.nextBaseFee = new(big.Int)
+		bf.results.nextBaseFee = new(big.Int)
 	}
-	bf.gasUsedRatio = float64(bf.header.GasUsed) / float64(bf.header.GasLimit)
+	bf.results.gasUsedRatio = float64(bf.header.GasUsed) / float64(bf.header.GasLimit)
 	if len(percentiles) == 0 {
 		// rewards were not requested, return null
 		return
@@ -100,11 +103,11 @@ func (oracle *Oracle) processBlock(bf *blockFees, percentiles []float64) {
 		return
 	}
 
-	bf.reward = make([]*big.Int, len(percentiles))
+	bf.results.reward = make([]*big.Int, len(percentiles))
 	if len(bf.block.Transactions()) == 0 {
 		// return an all zero row if there are no transactions to gather data from
-		for i := range bf.reward {
-			bf.reward[i] = new(big.Int)
+		for i := range bf.results.reward {
+			bf.results.reward[i] = new(big.Int)
 		}
 		return
 	}
@@ -125,7 +128,7 @@ func (oracle *Oracle) processBlock(bf *blockFees, percentiles []float64) {
 			txIndex++
 			sumGasUsed += sorter[txIndex].gasUsed
 		}
-		bf.reward[i] = sorter[txIndex].reward
+		bf.results.reward[i] = sorter[txIndex].reward
 	}
 }
 
@@ -134,7 +137,7 @@ func (oracle *Oracle) processBlock(bf *blockFees, percentiles []float64) {
 // also returned if requested and available.
 // Note: an error is only returned if retrieving the head header has failed. If there are no
 // retrievable blocks in the specified range then zero block count is returned with no error.
-func (oracle *Oracle) resolveBlockRange(ctx context.Context, lastBlock rpc.BlockNumber, blocks, maxHistory int) (*types.Block, []*types.Receipt, uint64, int, error) {
+func (oracle *Oracle) resolveBlockRange(ctx context.Context, lastBlock rpc.BlockNumber, blocks int) (*types.Block, []*types.Receipt, uint64, int, error) {
 	var (
 		headBlock       rpc.BlockNumber
 		pendingBlock    *types.Block
@@ -167,17 +170,6 @@ func (oracle *Oracle) resolveBlockRange(ctx context.Context, lastBlock rpc.Block
 	} else if pendingBlock == nil && lastBlock > headBlock {
 		return nil, nil, 0, 0, fmt.Errorf("%w: requested %d, head %d", errRequestBeyondHead, lastBlock, headBlock)
 	}
-	if maxHistory != 0 {
-		// limit retrieval to the given number of latest blocks
-		if tooOldCount := int64(headBlock) - int64(maxHistory) - int64(lastBlock) + int64(blocks); tooOldCount > 0 {
-			// tooOldCount is the number of requested blocks that are too old to be served
-			if int64(blocks) > tooOldCount {
-				blocks -= int(tooOldCount)
-			} else {
-				return nil, nil, 0, 0, nil
-			}
-		}
-	}
 	// ensure not trying to retrieve before genesis
 	if rpc.BlockNumber(blocks) > lastBlock+1 {
 		blocks = int(lastBlock + 1)
@@ -202,6 +194,10 @@ func (oracle *Oracle) FeeHistory(ctx context.Context, blocks int, unresolvedLast
 	if blocks < 1 {
 		return common.Big0, nil, nil, nil, nil // returning with no data and no error means there are no retrievable blocks
 	}
+	maxFeeHistory := oracle.maxHeaderHistory
+	if len(rewardPercentiles) != 0 {
+		maxFeeHistory = oracle.maxBlockHistory
+	}
 	if blocks > maxFeeHistory {
 		log.Warn("Sanitizing fee history length", "requested", blocks, "truncated", maxFeeHistory)
 		blocks = maxFeeHistory
@@ -214,17 +210,12 @@ func (oracle *Oracle) FeeHistory(ctx context.Context, blocks int, unresolvedLast
 			return common.Big0, nil, nil, nil, fmt.Errorf("%w: #%d:%f > #%d:%f", errInvalidPercentile, i-1, rewardPercentiles[i-1], i, p)
 		}
 	}
-	// Only process blocks if reward percentiles were requested
-	maxHistory := oracle.maxHeaderHistory
-	if len(rewardPercentiles) != 0 {
-		maxHistory = oracle.maxBlockHistory
-	}
 	var (
 		pendingBlock    *types.Block
 		pendingReceipts []*types.Receipt
 		err             error
 	)
-	pendingBlock, pendingReceipts, lastBlock, blocks, err := oracle.resolveBlockRange(ctx, unresolvedLastBlock, blocks, maxHistory)
+	pendingBlock, pendingReceipts, lastBlock, blocks, err := oracle.resolveBlockRange(ctx, unresolvedLastBlock, blocks)
 	if err != nil || blocks == 0 {
 		return common.Big0, nil, nil, nil, err
 	}
@@ -234,6 +225,10 @@ func (oracle *Oracle) FeeHistory(ctx context.Context, blocks int, unresolvedLast
 		next    = oldestBlock
 		results = make(chan *blockFees, blocks)
 	)
+	percentileKey := make([]byte, 8*len(rewardPercentiles))
+	for i, p := range rewardPercentiles {
+		binary.LittleEndian.PutUint64(percentileKey[i*8:(i+1)*8], math.Float64bits(p))
+	}
 	for i := 0; i < maxBlockFetchers && i < blocks; i++ {
 		go func() {
 			for {
@@ -246,24 +241,38 @@ func (oracle *Oracle) FeeHistory(ctx context.Context, blocks int, unresolvedLast
 				fees := &blockFees{blockNumber: blockNumber}
 				if pendingBlock != nil && blockNumber >= pendingBlock.NumberU64() {
 					fees.block, fees.receipts = pendingBlock, pendingReceipts
+					fees.header = fees.block.Header()
+					oracle.processBlock(fees, rewardPercentiles)
+					results <- fees
 				} else {
-					if len(rewardPercentiles) != 0 {
-						fees.block, fees.err = oracle.backend.BlockByNumber(ctx, rpc.BlockNumber(blockNumber))
-						if fees.block != nil && fees.err == nil {
-							fees.receipts, fees.err = oracle.backend.GetReceipts(ctx, fees.block.Hash())
-						}
+					cacheKey := struct {
+						number      uint64
+						percentiles string
+					}{blockNumber, string(percentileKey)}
+
+					if p, ok := oracle.historyCache.Get(cacheKey); ok {
+						fees.results = p.(processedFees)
+						results <- fees
 					} else {
-						fees.header, fees.err = oracle.backend.HeaderByNumber(ctx, rpc.BlockNumber(blockNumber))
+						if len(rewardPercentiles) != 0 {
+							fees.block, fees.err = oracle.backend.BlockByNumber(ctx, rpc.BlockNumber(blockNumber))
+							if fees.block != nil && fees.err == nil {
+								fees.receipts, fees.err = oracle.backend.GetReceipts(ctx, fees.block.Hash())
+								fees.header = fees.block.Header()
+							}
+						} else {
+							fees.header, fees.err = oracle.backend.HeaderByNumber(ctx, rpc.BlockNumber(blockNumber))
+						}
+						if fees.header != nil && fees.err == nil {
+							oracle.processBlock(fees, rewardPercentiles)
+							if fees.err == nil {
+								oracle.historyCache.Add(cacheKey, fees.results)
+							}
+						}
+						// send to results even if empty to guarantee that blocks items are sent in total
+						results <- fees
 					}
 				}
-				if fees.block != nil {
-					fees.header = fees.block.Header()
-				}
-				if fees.header != nil {
-					oracle.processBlock(fees, rewardPercentiles)
-				}
-				// send to results even if empty to guarantee that blocks items are sent in total
-				results <- fees
 			}
 		}()
 	}
@@ -279,8 +288,8 @@ func (oracle *Oracle) FeeHistory(ctx context.Context, blocks int, unresolvedLast
 			return common.Big0, nil, nil, nil, fees.err
 		}
 		i := int(fees.blockNumber - oldestBlock)
-		if fees.header != nil {
-			reward[i], baseFee[i], baseFee[i+1], gasUsedRatio[i] = fees.reward, fees.baseFee, fees.nextBaseFee, fees.gasUsedRatio
+		if fees.results.baseFee != nil {
+			reward[i], baseFee[i], baseFee[i+1], gasUsedRatio[i] = fees.results.reward, fees.results.baseFee, fees.results.nextBaseFee, fees.results.gasUsedRatio
 		} else {
 			// getting no block and no error means we are requesting into the future (might happen because of a reorg)
 			if i < firstMissing {

eth/gasprice/feehistory_test.go

@@ -36,20 +36,20 @@ func TestFeeHistory(t *testing.T) {
 		expCount            int
 		expErr              error
 	}{
-		{false, 0, 0, 10, 30, nil, 21, 10, nil},
-		{false, 0, 0, 10, 30, []float64{0, 10}, 21, 10, nil},
-		{false, 0, 0, 10, 30, []float64{20, 10}, 0, 0, errInvalidPercentile},
-		{false, 0, 0, 1000000000, 30, nil, 0, 31, nil},
-		{false, 0, 0, 1000000000, rpc.LatestBlockNumber, nil, 0, 33, nil},
-		{false, 0, 0, 10, 40, nil, 0, 0, errRequestBeyondHead},
-		{true, 0, 0, 10, 40, nil, 0, 0, errRequestBeyondHead},
+		{false, 1000, 1000, 10, 30, nil, 21, 10, nil},
+		{false, 1000, 1000, 10, 30, []float64{0, 10}, 21, 10, nil},
+		{false, 1000, 1000, 10, 30, []float64{20, 10}, 0, 0, errInvalidPercentile},
+		{false, 1000, 1000, 1000000000, 30, nil, 0, 31, nil},
+		{false, 1000, 1000, 1000000000, rpc.LatestBlockNumber, nil, 0, 33, nil},
+		{false, 1000, 1000, 10, 40, nil, 0, 0, errRequestBeyondHead},
+		{true, 1000, 1000, 10, 40, nil, 0, 0, errRequestBeyondHead},
 		{false, 20, 2, 100, rpc.LatestBlockNumber, nil, 13, 20, nil},
 		{false, 20, 2, 100, rpc.LatestBlockNumber, []float64{0, 10}, 31, 2, nil},
 		{false, 20, 2, 100, 32, []float64{0, 10}, 31, 2, nil},
-		{false, 0, 0, 1, rpc.PendingBlockNumber, nil, 0, 0, nil},
-		{false, 0, 0, 2, rpc.PendingBlockNumber, nil, 32, 1, nil},
-		{true, 0, 0, 2, rpc.PendingBlockNumber, nil, 32, 2, nil},
-		{true, 0, 0, 2, rpc.PendingBlockNumber, []float64{0, 10}, 32, 2, nil},
+		{false, 1000, 1000, 1, rpc.PendingBlockNumber, nil, 0, 0, nil},
+		{false, 1000, 1000, 2, rpc.PendingBlockNumber, nil, 32, 1, nil},
+		{true, 1000, 1000, 2, rpc.PendingBlockNumber, nil, 32, 2, nil},
+		{true, 1000, 1000, 2, rpc.PendingBlockNumber, []float64{0, 10}, 32, 2, nil},
 	}
 	for i, c := range cases {
 		config := Config{

eth/gasprice/gasprice.go

@@ -23,10 +23,13 @@ import (
 	"sync"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/log"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
+	lru "github.com/hashicorp/golang-lru"
 )
 
 const sampleNumber = 3 // Number of transactions sampled in a block
@@ -53,6 +56,7 @@ type OracleBackend interface {
 	GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error)
 	PendingBlockAndReceipts() (*types.Block, types.Receipts)
 	ChainConfig() *params.ChainConfig
+	SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription
 }
 
 // Oracle recommends gas prices based on the content of recent
@@ -68,6 +72,7 @@ type Oracle struct {
 
 	checkBlocks, percentile           int
 	maxHeaderHistory, maxBlockHistory int
+	historyCache                      *lru.Cache
 }
 
 // NewOracle returns a new gasprice oracle which can recommend suitable
@@ -99,6 +104,20 @@ func NewOracle(backend OracleBackend, params Config) *Oracle {
 	} else if ignorePrice.Int64() > 0 {
 		log.Info("Gasprice oracle is ignoring threshold set", "threshold", ignorePrice)
 	}
+
+	cache, _ := lru.New(2048)
+	headEvent := make(chan core.ChainHeadEvent, 1)
+	backend.SubscribeChainHeadEvent(headEvent)
+	go func() {
+		var lastHead common.Hash
+		for ev := range headEvent {
+			if ev.Block.ParentHash() != lastHead {
+				cache.Purge()
+			}
+			lastHead = ev.Block.Hash()
+		}
+	}()
+
 	return &Oracle{
 		backend:          backend,
 		lastPrice:        params.Default,
@@ -108,6 +127,7 @@ func NewOracle(backend OracleBackend, params Config) *Oracle {
 		percentile:       percent,
 		maxHeaderHistory: params.MaxHeaderHistory,
 		maxBlockHistory:  params.MaxBlockHistory,
+		historyCache:     cache,
 	}
 }
 

eth/gasprice/gasprice_test.go

@@ -29,6 +29,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/core/vm"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
 )
@@ -90,6 +91,10 @@ func (b *testBackend) ChainConfig() *params.ChainConfig {
 	return b.chain.Config()
 }
 
+func (b *testBackend) SubscribeChainHeadEvent(ch chan<- core.ChainHeadEvent) event.Subscription {
+	return nil
+}
+
 func newTestBackend(t *testing.T, londonBlock *big.Int, pending bool) *testBackend {
 	var (
 		key, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")