fix bug on the reuse

Signed-off-by: Alan Protasio <alanprot@gmail.com>

pkg/cortexpb/slicesPool.go

@@ -40,6 +40,7 @@ func (sp *byteSlicePools) getSlice(size int) *[]byte {
 		return &buf
 	}
 
+	// if the size is < than the minPoolSizePower we return an array from the first pool
 	if index < 0 {
 		index = 0
 	}
@@ -52,13 +53,9 @@ func (sp *byteSlicePools) getSlice(size int) *[]byte {
 func (sp *byteSlicePools) reuseSlice(s *[]byte) {
 	index := int(math.Floor(math.Log2(float64(cap(*s))))) - minPoolSizePower
 
-	if index >= len(sp.pools) {
+	if index >= len(sp.pools) || index < 0 {
 		return
 	}
 
-	if index < 0 {
-		index = 0
-	}
-
 	sp.pools[index].Put(s)
 }

pkg/cortexpb/slicesPool_test.go

@@ -19,3 +19,12 @@ func TestFuzzyByteSlicePools(t *testing.T) {
 		sut.reuseSlice(s)
 	}
 }
+
+func TestReturnSliceSmallerThanMin(t *testing.T) {
+	sut := newSlicePool(20)
+	size := 3
+	buff := make([]byte, 0, size)
+	sut.reuseSlice(&buff)
+	buff2 := sut.getSlice(size * 2)
+	assert.Equal(t, len(*buff2), size*2)
+}

pkg/cortexpb/timeseries.go

@@ -98,7 +98,9 @@ func ReuseWriteRequest(req *PreallocWriteRequest) {
 		bytePool.reuseSlice(req.data)
 		req.data = nil
 	}
-
+	req.Source = 0
+	req.Metadata = nil
+	req.Timeseries = nil
 	writeRequestPool.Put(req)
 }