Merge pull request #14470 from bboreham/label-sep-byte

Labels: use single byte as separator - small speedup

model/labels/labels.go

@@ -38,10 +38,10 @@ func (ls Labels) Bytes(buf []byte) []byte {
 	b.WriteByte(labelSep)
 	for i, l := range ls {
 		if i > 0 {
-			b.WriteByte(seps[0])
+			b.WriteByte(sep)
 		}
 		b.WriteString(l.Name)
-		b.WriteByte(seps[0])
+		b.WriteByte(sep)
 		b.WriteString(l.Value)
 	}
 	return b.Bytes()
@@ -86,9 +86,9 @@ func (ls Labels) Hash() uint64 {
 		}
 
 		b = append(b, v.Name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, v.Value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 	}
 	return xxhash.Sum64(b)
 }
@@ -106,9 +106,9 @@ func (ls Labels) HashForLabels(b []byte, names ...string) (uint64, []byte) {
 			i++
 		default:
 			b = append(b, ls[i].Name...)
-			b = append(b, seps[0])
+			b = append(b, sep)
 			b = append(b, ls[i].Value...)
-			b = append(b, seps[0])
+			b = append(b, sep)
 			i++
 			j++
 		}
@@ -130,9 +130,9 @@ func (ls Labels) HashWithoutLabels(b []byte, names ...string) (uint64, []byte) {
 			continue
 		}
 		b = append(b, ls[i].Name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, ls[i].Value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 	}
 	return xxhash.Sum64(b), b
 }
@@ -151,10 +151,10 @@ func (ls Labels) BytesWithLabels(buf []byte, names ...string) []byte {
 			i++
 		default:
 			if b.Len() > 1 {
-				b.WriteByte(seps[0])
+				b.WriteByte(sep)
 			}
 			b.WriteString(ls[i].Name)
-			b.WriteByte(seps[0])
+			b.WriteByte(sep)
 			b.WriteString(ls[i].Value)
 			i++
 			j++
@@ -177,10 +177,10 @@ func (ls Labels) BytesWithoutLabels(buf []byte, names ...string) []byte {
 			continue
 		}
 		if b.Len() > 1 {
-			b.WriteByte(seps[0])
+			b.WriteByte(sep)
 		}
 		b.WriteString(ls[i].Name)
-		b.WriteByte(seps[0])
+		b.WriteByte(sep)
 		b.WriteString(ls[i].Value)
 	}
 	return b.Bytes()

model/labels/labels_common.go

@@ -29,10 +29,11 @@ const (
 	BucketLabel  = "le"
 	InstanceName = "instance"
 
-	labelSep = '\xfe'
+	labelSep = '\xfe' // Used at beginning of `Bytes` return.
+	sep      = '\xff' // Used between labels in `Bytes` and `Hash`.
 )
 
-var seps = []byte{'\xff'}
+var seps = []byte{sep} // Used with Hash, which has no WriteByte method.
 
 // Label is a key/value pair of strings.
 type Label struct {

model/labels/labels_dedupelabels.go

@@ -146,13 +146,13 @@ func (ls Labels) Bytes(buf []byte) []byte {
 	b := bytes.NewBuffer(buf[:0])
 	for i := 0; i < len(ls.data); {
 		if i > 0 {
-			b.WriteByte(seps[0])
+			b.WriteByte(sep)
 		}
 		var name, value string
 		name, i = decodeString(ls.syms, ls.data, i)
 		value, i = decodeString(ls.syms, ls.data, i)
 		b.WriteString(name)
-		b.WriteByte(seps[0])
+		b.WriteByte(sep)
 		b.WriteString(value)
 	}
 	return b.Bytes()
@@ -201,9 +201,9 @@ func (ls Labels) Hash() uint64 {
 		}
 
 		b = append(b, name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		pos = newPos
 	}
 	return xxhash.Sum64(b)
@@ -226,9 +226,9 @@ func (ls Labels) HashForLabels(b []byte, names ...string) (uint64, []byte) {
 		}
 		if name == names[j] {
 			b = append(b, name...)
-			b = append(b, seps[0])
+			b = append(b, sep)
 			b = append(b, value...)
-			b = append(b, seps[0])
+			b = append(b, sep)
 		}
 	}
 
@@ -252,9 +252,9 @@ func (ls Labels) HashWithoutLabels(b []byte, names ...string) (uint64, []byte) {
 			continue
 		}
 		b = append(b, name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 	}
 	return xxhash.Sum64(b), b
 }
@@ -275,10 +275,10 @@ func (ls Labels) BytesWithLabels(buf []byte, names ...string) []byte {
 		}
 		if lName == names[j] {
 			if b.Len() > 1 {
-				b.WriteByte(seps[0])
+				b.WriteByte(sep)
 			}
 			b.WriteString(lName)
-			b.WriteByte(seps[0])
+			b.WriteByte(sep)
 			b.WriteString(lValue)
 		}
 		pos = newPos
@@ -299,10 +299,10 @@ func (ls Labels) BytesWithoutLabels(buf []byte, names ...string) []byte {
 		}
 		if j == len(names) || lName != names[j] {
 			if b.Len() > 1 {
-				b.WriteByte(seps[0])
+				b.WriteByte(sep)
 			}
 			b.WriteString(lName)
-			b.WriteByte(seps[0])
+			b.WriteByte(sep)
 			b.WriteString(lValue)
 		}
 		pos = newPos

model/labels/labels_stringlabels.go

@@ -112,9 +112,9 @@ func (ls Labels) HashForLabels(b []byte, names ...string) (uint64, []byte) {
 		}
 		if name == names[j] {
 			b = append(b, name...)
-			b = append(b, seps[0])
+			b = append(b, sep)
 			b = append(b, value...)
-			b = append(b, seps[0])
+			b = append(b, sep)
 		}
 	}
 
@@ -138,9 +138,9 @@ func (ls Labels) HashWithoutLabels(b []byte, names ...string) (uint64, []byte) {
 			continue
 		}
 		b = append(b, name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 	}
 	return xxhash.Sum64(b), b
 }

model/labels/sharding.go

@@ -39,9 +39,9 @@ func StableHash(ls Labels) uint64 {
 		}
 
 		b = append(b, v.Name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, v.Value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 	}
 	return xxhash.Sum64(b)
 }

model/labels/sharding_dedupelabels.go

@@ -43,9 +43,9 @@ func StableHash(ls Labels) uint64 {
 		}
 
 		b = append(b, name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		pos = newPos
 	}
 	return xxhash.Sum64(b)

model/labels/sharding_stringlabels.go

@@ -43,9 +43,9 @@ func StableHash(ls Labels) uint64 {
 		}
 
 		b = append(b, v.Name...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 		b = append(b, v.Value...)
-		b = append(b, seps[0])
+		b = append(b, sep)
 	}
 	if h != nil {
 		return h.Sum64()