VictoriaMetrics/lib/fs/reader_at_test.go
Aliaksandr Valialkin d120197676 lib/fs: optimize queries that read recent samples for big number of time series
Use standard copy() func instead of mmap-aware copy func for reading recently touched mmap-ed data.
This improves read performance by up to 4x.
2020-06-05 19:10:04 +03:00

37 lines
812 B
Go

package fs
import (
"fmt"
"io/ioutil"
"testing"
)
func TestReaderAt(t *testing.T) {
for _, bufSize := range []int{1, 1e1, 1e2, 1e3, 1e4, 1e5} {
t.Run(fmt.Sprintf("%d", bufSize), func(t *testing.T) {
testReaderAt(t, bufSize)
})
}
}
func testReaderAt(t *testing.T, bufSize int) {
path := "TestReaderAt"
const fileSize = 8 * 1024 * 1024
data := make([]byte, fileSize)
if err := ioutil.WriteFile(path, data, 0600); err != nil {
t.Fatalf("cannot create %q: %s", path, err)
}
defer MustRemoveAll(path)
r, err := OpenReaderAt(path)
if err != nil {
t.Fatalf("error in OpenReaderAt(%q): %s", path, err)
}
defer r.MustClose()
buf := make([]byte, bufSize)
for i := 0; i < fileSize-bufSize; i += bufSize {
offset := int64(i)
r.MustReadAt(buf[:0], offset)
r.MustReadAt(buf, offset)
}
}