コード例 #1
0
ファイル: db.go プロジェクト: mrG7/escher
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
}
コード例 #2
0
ファイル: corrupt_test.go プロジェクト: mrG7/escher
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()
}