/*
1KB ReadAt calls before:
fileread_test.go:253: Blob Size: 4194304 raw, 4201523 with meta (1.00172x)
fileread_test.go:283: Blobs fetched: 4160 (63.03x)
fileread_test.go:284: Bytes fetched: 361174780 (85.96x)
2KB ReadAt calls before:
fileread_test.go:253: Blob Size: 4194304 raw, 4201523 with meta (1.00172x)
fileread_test.go:283: Blobs fetched: 2112 (32.00x)
fileread_test.go:284: Bytes fetched: 182535389 (43.45x)
After fix:
fileread_test.go:253: Blob Size: 4194304 raw, 4201523 with meta (1.00172x)
fileread_test.go:283: Blobs fetched: 66 (1.00x)
fileread_test.go:284: Bytes fetched: 4201523 (1.00x)
*/
func TestReaderEfficiency(t *testing.T) {
const fileSize = 4 << 20
bigFile := make([]byte, fileSize)
rnd := rand.New(rand.NewSource(1))
for i := range bigFile {
bigFile[i] = byte(rnd.Intn(256))
}
sto := new(test.Fetcher) // in-memory blob storage
fileMap := NewFileMap("testfile")
fileref, err := WriteFileMap(sto, fileMap, bytes.NewReader(bigFile))
if err != nil {
t.Fatalf("WriteFileMap: %v", err)
}
fr, err := NewFileReader(sto, fileref)
if err != nil {
t.Fatal(err)
}
numBlobs := sto.NumBlobs()
t.Logf("Num blobs = %d", numBlobs)
sumSize := sto.SumBlobSize()
t.Logf("Blob Size: %d raw, %d with meta (%.05fx)", fileSize, sumSize, float64(sumSize)/float64(fileSize))
const readSize = 2 << 10
buf := make([]byte, readSize)
for off := int64(0); off < fileSize; off += readSize {
n, err := fr.ReadAt(buf, off)
if err != nil {
t.Fatalf("ReadAt at offset %d: %v", off, err)
}
if n != readSize {
t.Fatalf("Read %d bytes at offset %d; want %d", n, off, readSize)
}
got, want := buf, bigFile[off:off+readSize]
if !bytes.Equal(buf, want) {
t.Errorf("Incorrect read at offset %d:\n got: %s\n want: %s", off, summary(got), summary(want))
off := 0
for len(got) > 0 && len(want) > 0 && got[0] == want[0] {
off++
got = got[1:]
want = want[1:]
}
t.Errorf(" differences start at offset %d:\n got: %s\n want: %s\n", off, summary(got), summary(want))
break
}
}
fr.Close()
blobsFetched, bytesFetched := sto.Stats()
if blobsFetched != int64(numBlobs) {
t.Errorf("Fetched %d blobs; want %d", blobsFetched, numBlobs)
}
if bytesFetched != sumSize {
t.Errorf("Fetched %d bytes; want %d", bytesFetched, sumSize)
}
}
