func (db *DB) recoverJournal() error {
// Get all tables and sort it by file number.
journalFiles_, err := db.s.getFiles(storage.TypeJournal)
if err != nil {
return err
}
journalFiles := files(journalFiles_)
journalFiles.sort()
// Discard older journal.
prev := -1
for i, file := range journalFiles {
if file.Num() >= db.s.stJournalNum {
if prev >= 0 {
i--
journalFiles[i] = journalFiles[prev]
}
journalFiles = journalFiles[i:]
break
} else if file.Num() == db.s.stPrevJournalNum {
prev = i
}
}
var jr *journal.Reader
var of storage.File
var mem *memdb.DB
batch := new(Batch)
cm := newCMem(db.s)
buf := new(util.Buffer)
// Options.
strict := db.s.o.GetStrict(opt.StrictJournal)
checksum := db.s.o.GetStrict(opt.StrictJournalChecksum)
writeBuffer := db.s.o.GetWriteBuffer()
recoverJournal := func(file storage.File) error {
db.logf("journal@recovery recovering @%d", file.Num())
reader, err := file.Open()
if err != nil {
return err
}
defer reader.Close()
// Create/reset journal reader instance.
if jr == nil {
jr = journal.NewReader(reader, dropper{db.s, file}, strict, checksum)
} else {
jr.Reset(reader, dropper{db.s, file}, strict, checksum)
}
// Flush memdb and remove obsolete journal file.
if of != nil {
if mem.Len() > 0 {
if err := cm.flush(mem, 0); err != nil {
return err
}
}
if err := cm.commit(file.Num(), db.seq); err != nil {
return err
}
cm.reset()
of.Remove()
of = nil
}
// Replay journal to memdb.
mem.Reset()
for {
r, err := jr.Next()
if err != nil {
if err == io.EOF {
break
}
return err
}
buf.Reset()
if _, err := buf.ReadFrom(r); err != nil {
if err == io.ErrUnexpectedEOF {
continue
} else {
return err
}
}
if err := batch.decode(buf.Bytes()); err != nil {
return err
}
if err := batch.memReplay(mem); err != nil {
return err
}
// Save sequence number.
db.seq = batch.seq + uint64(batch.len())
// Flush it if large enough.
if mem.Size() >= writeBuffer {
if err := cm.flush(mem, 0); err != nil {
return err
}
mem.Reset()
}
}
of = file
return nil
}
// Recover all journals.
if len(journalFiles) > 0 {
db.logf("journal@recovery F·%d", len(journalFiles))
// Mark file number as used.
db.s.markFileNum(journalFiles[len(journalFiles)-1].Num())
mem = memdb.New(db.s.icmp, writeBuffer)
for _, file := range journalFiles {
if err := recoverJournal(file); err != nil {
return err
}
}
// Flush the last journal.
if mem.Len() > 0 {
if err := cm.flush(mem, 0); err != nil {
return err
}
}
}
// Create a new journal.
if _, err := db.newMem(0); err != nil {
return err
}
// Commit.
if err := cm.commit(db.journalFile.Num(), db.seq); err != nil {
// Close journal.
if db.journal != nil {
db.journal.Close()
db.journalWriter.Close()
}
return err
}
// Remove the last obsolete journal file.
if of != nil {
of.Remove()
}
return nil
}
func (h *dbCorruptHarness) corrupt(ft storage.FileType, offset, n int) {
p := &h.dbHarness
t := p.t
var file storage.File
ff, _ := p.stor.GetFiles(ft)
for _, f := range ff {
if file == nil || f.Num() > file.Num() {
file = f
}
}
if file == nil {
t.Fatalf("no such file with type %q", ft)
}
r, err := file.Open()
if err != nil {
t.Fatal("cannot open file: ", err)
}
x, err := r.Seek(0, 2)
if err != nil {
t.Fatal("cannot query file size: ", err)
}
m := int(x)
if _, err := r.Seek(0, 0); err != nil {
t.Fatal(err)
}
if offset < 0 {
if -offset > m {
offset = 0
} else {
offset = m + offset
}
}
if offset > m {
offset = m
}
if offset+n > m {
n = m - offset
}
buf := make([]byte, m)
_, err = io.ReadFull(r, buf)
if err != nil {
t.Fatal("cannot read file: ", err)
}
r.Close()
for i := 0; i < n; i++ {
buf[offset+i] ^= 0x80
}
err = file.Remove()
if err != nil {
t.Fatal("cannot remove old file: ", err)
}
w, err := file.Create()
if err != nil {
t.Fatal("cannot create new file: ", err)
}
_, err = w.Write(buf)
if err != nil {
t.Fatal("cannot write new file: ", err)
}
w.Close()
}