func (db *DB) Recovery(b []byte) error {
buf := bytes.NewBuffer(b)
db.setCurrent(uint64(binary.ReadInt64(buf)))
db.MostRecent = binary.ReadInt64(buf)
count := int(binary.ReadUvarint(buf))
for i := 0; i < count; i++ {
db.addClosed(uint64(binary.ReadInt64(buf)))
}
return nil
}
func TestWriteIndexBlocksLarge(t *testing.T) {
w := new(bytes.Buffer)
index := &index{evs: make(events, 5000)}
for i := 0; i < 5000; i++ {
index.evs[i] = &Event{Timestamp: i, block: rand.Int63(), offset: rand.Intn(4096)}
}
writeIndexBlocks(index, w)
if index.length != 50040 {
t.Errorf("Wrong written length: wanted: 50040, found: %d", index.length)
}
reader := blocks.NewByteReader(w.Bytes(), 4096)
for i, event := range index.evs {
block := binary.ReadInt64(reader)
offset := binary.ReadInt16(reader)
if event.block != block || event.offset != int(offset) {
t.Errorf("Case %d: Wrong read event block/offset. wanted: %d,%d found: %d,%d", i, event.block, event.offset, block, offset)
}
}
}
func (s *Space) ScanIndex(name, value string, scanner Scanner) {
if reader := s.findIndex(name, value); reader != nil {
for {
// If the next byte is 0, then that's an empty event offset,
// marking the end of the index. Nothing more to see here.
if next := reader.Peek(1); len(next) == 0 || next[0] == 0 {
return
}
// Each entry in the index is a 64 bit integer for the
// event's block offset in the file, and a 16 bit integer
// for the event's offset within the block (as each block
// is 4096 bytes long)
block := binary.ReadInt64(reader)
offset := binary.ReadInt16(reader)
// Move to the event's block
s.blocks.Seek(s.offset+block, 0)
// Read all data prior to the current event's offset.
binary.ReadBytes(s.blocks, offset)
event := pullEvent(s.blocks)
if event == nil || !scanner(event) {
return
}
}
}
}
func findIndex(f *os.File) (*sst.Reader, error) {
// The last 8 bytes in the file is the length
// of the SSTable spaces index.
f.Seek(-8, 2)
indexLen := binary.ReadInt64(f)
return sst.NewReader(bounded.New(f, -8-indexLen, -8), indexLen)
}
func findSpaceIndex(r io.ReadSeeker, offset, length int64) (*sst.Reader, error) {
footerOffset := offset + length - 8
// The last 8 bytes in the file is the length
// of the SSTable grouping index.
r.Seek(footerOffset, 0)
indexLen := binary.ReadInt64(r)
return sst.NewReader(bounded.New(r, footerOffset-indexLen, footerOffset), indexLen)
}
// Finds and returns a space by it's id.
func (db *Db) Find(id []byte) *Space {
if val, err := db.index.Get(id); err == nil {
b := bytes.NewReader(val)
// The entry in the SSTable index is
// the offset and length of the space
// within the file.
offset := binary.ReadInt64(b)
length := binary.ReadInt64(b)
return openSpace(
db.file,
id,
offset,
length,
)
}
return nil
}
func TestWriteIndexBlocksSmall(t *testing.T) {
w := new(bytes.Buffer)
e1 := &Event{Timestamp: 1, block: 0, offset: 2048}
e2 := &Event{Timestamp: 3, block: 512, offset: 128}
e3 := &Event{Timestamp: 2, block: 2048, offset: 512}
e4 := &Event{Timestamp: 4, block: 248, offset: 1024}
index := &index{evs: events{e1, e2, e3, e4}}
writeIndexBlocks(index, w)
if index.length != 36 {
t.Errorf("Wrong written length: wanted: 36, found: %d", index.length)
}
compressed, _ := csnappy.Encode(nil, []byte(
"\xF8\x00\x00\x00\x00\x00\x00\x00"+"\x00\x04"+
"\x00\x02\x00\x00\x00\x00\x00\x00"+"\x80\x00"+
"\x00\x08\x00\x00\x00\x00\x00\x00"+"\x00\x02"+
"\x00\x00\x00\x00\x00\x00\x00\x00"+"\x00\x08"+
"\x00"))
expected := append([]byte("\x21\x00\x01"), compressed...)
if !reflect.DeepEqual(w.Bytes(), expected) {
t.Errorf("Wrong event block bytecode:\n wanted: %x\n found: %x", expected, w.Bytes())
}
want := events{e4, e2, e3, e1}
if !reflect.DeepEqual(index.evs, want) {
t.Errorf("Wrongly sorted events: wanted: %v found: %v", want, index.evs)
}
reader := blocks.NewByteReader(w.Bytes(), 4096)
for i, event := range index.evs {
block := binary.ReadInt64(reader)
offset := binary.ReadInt16(reader)
if event.block != block || event.offset != int(offset) {
t.Errorf("Case %d: Wrong read event block/offset. wanted: %d,%d found: %d,%d", i, event.block, event.offset, block, offset)
}
}
}
func TestWriteSpaceIndexes(t *testing.T) {
w := new(bytes.Buffer)
writer := newSpace(w, []byte("a"))
e1data := []byte("abc")
e2data := []byte("b")
e3data := []byte("c")
e4data := []byte("def")
e1 := newEvent(e1data, 1)
e2 := newEvent(e2data, 3)
e3 := newEvent(e3data, 2)
e4 := newEvent(e4data, 4)
writer.add(e1, "1", map[string]string{"a": "1"})
writer.add(e2, "1", map[string]string{"a": "2"})
writer.add(e3, "1", map[string]string{"a": "2"})
writer.add(e4, "1", map[string]string{"a": "1"})
writer.write()
var tests = []struct {
key string
offset int
length int
evs [][]byte
indexed events
}{
{"g1", 1, 32, [][]byte{e4data, e2data, e3data, e1data}, nil},
{"ia:1", 33, 21, nil, events{e4, e1}},
{"ia:2", 54, 23, nil, events{e2, e3}},
}
sst, _ := findSpaceIndex(bytes.NewReader(w.Bytes()), 0, int64(w.Len()))
for i, test := range tests {
val, _ := sst.Get([]byte(test.key))
r := bytes.NewReader(val)
offset := binary.ReadUvarint(r)
length := binary.ReadUvarint(r)
if int(offset) != test.offset || int(length) != test.length {
t.Errorf("Case %d: Wrong grouping encoding: want: %d,%d found: %d,%d", i, test.offset, test.length, offset, length)
}
reader := blocks.NewByteReader(w.Bytes(), 4096)
reader.Seek(int64(offset), 0)
if len(test.evs) > 0 {
for j, data := range test.evs {
if e := pullEvent(reader); !reflect.DeepEqual(e.Data, data) {
t.Errorf("Case %d/%d: Wrong event found: want: %s found: %s", i, j, data, e.Data)
}
}
if e := pullEvent(reader); e != nil {
t.Errorf("Wrong event found: want: nil found: %s", e.Data)
}
}
for j, event := range test.indexed {
block := binary.ReadInt64(reader)
offset := binary.ReadInt16(reader)
if block != event.block || int(offset) != event.offset {
t.Errorf("Case %d/%d: Wrong event index: want: %d,%d found: %d,%d", i, j, event.block, event.offset, block, offset)
}
}
}
}