use fixed gas price since bsc network is idle

eth/config.go

@@ -61,8 +61,9 @@ var DefaultConfig = Config{
 	},
 	TxPool: core.DefaultTxPoolConfig,
 	GPO: gasprice.Config{
-		Blocks:     20,
-		Percentile: 60,
+		Blocks:          20,
+		Percentile:      60,
+		OracleThreshold: 1000,
 	},
 }
 

eth/gasprice/gasprice.go

@@ -32,9 +32,10 @@ import (
 var maxPrice = big.NewInt(500 * params.GWei)
 
 type Config struct {
-	Blocks     int
-	Percentile int
-	Default    *big.Int `toml:",omitempty"`
+	Blocks          int
+	Percentile      int
+	Default         *big.Int `toml:",omitempty"`
+	OracleThreshold int      `toml:",omitempty"`
 }
 
 // Oracle recommends gas prices based on the content of recent
@@ -46,6 +47,9 @@ type Oracle struct {
 	cacheLock sync.RWMutex
 	fetchLock sync.Mutex
 
+	defaultPrice    *big.Int
+	sampleThreshold int
+
 	checkBlocks, maxEmpty, maxBlocks int
 	percentile                       int
 }
@@ -64,12 +68,14 @@ func NewOracle(backend ethapi.Backend, params Config) *Oracle {
 		percent = 100
 	}
 	return &Oracle{
-		backend:     backend,
-		lastPrice:   params.Default,
-		checkBlocks: blocks,
-		maxEmpty:    blocks / 2,
-		maxBlocks:   blocks * 5,
-		percentile:  percent,
+		backend:         backend,
+		lastPrice:       params.Default,
+		defaultPrice:    params.Default,
+		checkBlocks:     blocks,
+		maxEmpty:        blocks / 2,
+		maxBlocks:       blocks * 5,
+		percentile:      percent,
+		sampleThreshold: params.OracleThreshold,
 	}
 }
 
@@ -132,9 +138,11 @@ func (gpo *Oracle) SuggestPrice(ctx context.Context) (*big.Int, error) {
 		}
 	}
 	price := lastPrice
-	if len(blockPrices) > 0 {
+	if len(blockPrices) > gpo.sampleThreshold {
 		sort.Sort(bigIntArray(blockPrices))
 		price = blockPrices[(len(blockPrices)-1)*gpo.percentile/100]
+	} else {
+		price = gpo.defaultPrice
 	}
 	if price.Cmp(maxPrice) > 0 {
 		price = new(big.Int).Set(maxPrice)