core, ethdb: define MaximumKey

core/rawdb/table.go

@@ -17,8 +17,6 @@
 package rawdb
 
 import (
-	"bytes"
-
 	"github.com/ethereum/go-ethereum/ethdb"
 )
 
@@ -137,7 +135,7 @@ func (t *table) DeleteRange(start, end []byte) error {
 	// The nilness will be lost by adding the prefix, explicitly converting it
 	// to a special flag representing the end of key range.
 	if end == nil {
-		end = bytes.Repeat([]byte{0xff}, 32)
+		end = ethdb.MaximumKey
 	}
 	return t.db.DeleteRange(append([]byte(t.prefix), start...), append([]byte(t.prefix), end...))
 }
@@ -235,7 +233,7 @@ func (b *tableBatch) DeleteRange(start, end []byte) error {
 	// The nilness will be lost by adding the prefix, explicitly converting it
 	// to a special flag representing the end of key range.
 	if end == nil {
-		end = bytes.Repeat([]byte{0xff}, 32)
+		end = ethdb.MaximumKey
 	}
 	return b.batch.DeleteRange(append([]byte(b.prefix), start...), append([]byte(b.prefix), end...))
 }

ethdb/database.go

@@ -18,10 +18,23 @@
 package ethdb
 
 import (
+	"bytes"
 	"errors"
 	"io"
 )
 
+var (
+	// MaximumKey is a special marker representing the largest possible key
+	// in the database.
+	//
+	// All prefixed database entries will be smaller than this marker.
+	// For trie nodes in hash mode, we use a 32-byte slice filled with 0xFF
+	// because there may be shared prefixes starting with multiple 0xFF bytes.
+	// Using 32 bytes ensures that only a hash collision could potentially
+	// match or exceed it.
+	MaximumKey = bytes.Repeat([]byte{0xff}, 32)
+)
+
 // KeyValueReader wraps the Has and Get method of a backing data store.
 type KeyValueReader interface {
 	// Has retrieves if a key is present in the key-value data store.

ethdb/pebble/pebble.go

@@ -18,7 +18,6 @@
 package pebble
 
 import (
-	"bytes"
 	"fmt"
 	"runtime"
 	"strings"
@@ -411,7 +410,7 @@ func (d *Database) DeleteRange(start, end []byte) error {
 	// in pebble(nil in leveldb). Use an ugly hack to construct a
 	// large key to represent it.
 	if end == nil {
-		end = bytes.Repeat([]byte{0xff}, 32)
+		end = ethdb.MaximumKey
 	}
 	return d.db.DeleteRange(start, end, d.writeOptions)
 }
@@ -471,7 +470,7 @@ func (d *Database) Compact(start []byte, limit []byte) error {
 	// 0xff-s, so 32 ensures than only a hash collision could touch it.
 	// https://github.com/cockroachdb/pebble/issues/2359#issuecomment-1443995833
 	if limit == nil {
-		limit = bytes.Repeat([]byte{0xff}, 32)
+		limit = ethdb.MaximumKey
 	}
 	return d.db.Compact(start, limit, true) // Parallelization is preferred
 }
@@ -633,7 +632,7 @@ func (b *batch) DeleteRange(start, end []byte) error {
 	// in pebble(nil in leveldb). Use an ugly hack to construct a
 	// large key to represent it.
 	if end == nil {
-		end = bytes.Repeat([]byte{0xff}, 32)
+		end = ethdb.MaximumKey
 	}
 	if err := b.b.DeleteRange(start, end, nil); err != nil {
 		return err