Copy returned bytes from TSI meta functions.

CHANGELOG.md

@@ -74,6 +74,7 @@
 - [#8908](https://github.com/influxdata/influxdb/issues/8908): Fix missing man pages in new packaging output
 - [#8909](https://github.com/influxdata/influxdb/issues/8909): Fix use of `INFLUXD_OPTS` in service file
 - [#8952](https://github.com/influxdata/influxdb/issues/8952): Fix WAL panic: runtime error: makeslice: cap out of range
+- [#8975](https://github.com/influxdata/influxdb/pull/8975): Copy returned bytes from TSI meta functions.
 
 ## v1.3.4 [unreleased]
 

pkg/bytesutil/bytesutil.go

@@ -88,6 +88,25 @@ func Intersect(a, b [][]byte) [][]byte {
 	return other
 }
 
+// Clone returns a copy of b.
+func Clone(b []byte) []byte {
+	if b == nil {
+		return nil
+	}
+	buf := make([]byte, len(b))
+	copy(buf, b)
+	return buf
+}
+
+// CloneSlice returns a copy of a slice of byte slices.
+func CloneSlice(a [][]byte) [][]byte {
+	other := make([][]byte, len(a))
+	for i := range a {
+		other[i] = Clone(a[i])
+	}
+	return other
+}
+
 type byteSlices [][]byte
 
 func (a byteSlices) Len() int           { return len(a) }

tsdb/index/tsi1/index.go

@@ -17,6 +17,7 @@ import (
 
 	"github.com/influxdata/influxdb/influxql"
 	"github.com/influxdata/influxdb/models"
+	"github.com/influxdata/influxdb/pkg/bytesutil"
 	"github.com/influxdata/influxdb/pkg/estimator"
 	"github.com/influxdata/influxdb/query"
 	"github.com/influxdata/influxdb/tsdb"
@@ -402,7 +403,11 @@ func (i *Index) MeasurementExists(name []byte) (bool, error) {
 func (i *Index) MeasurementNamesByExpr(expr influxql.Expr) ([][]byte, error) {
 	fs := i.RetainFileSet()
 	defer fs.Release()
-	return fs.MeasurementNamesByExpr(expr)
+
+	names, err := fs.MeasurementNamesByExpr(expr)
+
+	// Clone byte slices since they will be used after the fileset is released.
+	return bytesutil.CloneSlice(names), err
 }
 
 func (i *Index) MeasurementNamesByRegex(re *regexp.Regexp) ([][]byte, error) {
@@ -413,7 +418,8 @@ func (i *Index) MeasurementNamesByRegex(re *regexp.Regexp) ([][]byte, error) {
 	var a [][]byte
 	for e := itr.Next(); e != nil; e = itr.Next() {
 		if re.Match(e.Name()) {
-			a = append(a, e.Name())
+			// Clone bytes since they will be used after the fileset is released.
+			a = append(a, bytesutil.Clone(e.Name()))
 		}
 	}
 	return a, nil
@@ -726,7 +732,11 @@ func (i *Index) TagKeyCardinality(name, key []byte) int {
 func (i *Index) MeasurementSeriesKeysByExpr(name []byte, expr influxql.Expr) ([][]byte, error) {
 	fs := i.RetainFileSet()
 	defer fs.Release()
-	return fs.MeasurementSeriesKeysByExpr(name, expr, i.fieldset)
+
+	keys, err := fs.MeasurementSeriesKeysByExpr(name, expr, i.fieldset)
+
+	// Clone byte slices since they will be used after the fileset is released.
+	return bytesutil.CloneSlice(keys), err
 }
 
 // TagSets returns an ordered list of tag sets for a measurement by dimension

tsdb/index/tsi1/index_files.go

@@ -8,6 +8,7 @@ import (
 	"sort"
 	"time"
 
+	"github.com/influxdata/influxdb/pkg/bytesutil"
 	"github.com/influxdata/influxdb/pkg/estimator/hll"
 	"github.com/influxdata/influxdb/pkg/mmap"
 )
@@ -52,7 +53,7 @@ func (p *IndexFiles) MeasurementNames() [][]byte {
 	itr := p.MeasurementIterator()
 	var names [][]byte
 	for e := itr.Next(); e != nil; e = itr.Next() {
-		names = append(names, copyBytes(e.Name()))
+		names = append(names, bytesutil.Clone(e.Name()))
 	}
 	sort.Sort(byteSlices(names))
 	return names

tsdb/index/tsi1/tsi1.go

@@ -792,16 +792,6 @@ func (a byteSlices) Len() int           { return len(a) }
 func (a byteSlices) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
 func (a byteSlices) Less(i, j int) bool { return bytes.Compare(a[i], a[j]) == -1 }
 
-// copyBytes returns a copy of b.
-func copyBytes(b []byte) []byte {
-	if b == nil {
-		return nil
-	}
-	buf := make([]byte, len(b))
-	copy(buf, b)
-	return buf
-}
-
 // assert will panic with a given formatted message if the given condition is false.
 func assert(condition bool, msg string, v ...interface{}) {
 	if !condition {