Golang memdb.DB类代码示例

func decodeBatchToMem(data []byte, expectSeq uint64, mdb *memdb.DB) (seq uint64, batchLen int, err error) {
	seq, batchLen, err = decodeBatchHeader(data)
	if err != nil {
		return 0, 0, err
	}
	if seq < expectSeq {
		return 0, 0, newErrBatchCorrupted("invalid sequence number")
	}
	data = data[batchHeaderLen:]
	var ik []byte
	var decodedLen int
	err = decodeBatch(data, func(i int, index batchIndex) error {
		if i >= batchLen {
			return newErrBatchCorrupted("invalid records length")
		}
		ik = makeInternalKey(ik, index.k(data), seq+uint64(i), index.keyType)
		if err := mdb.Put(ik, index.v(data)); err != nil {
			return err
		}
		decodedLen++
		return nil
	})
	if err == nil && decodedLen != batchLen {
		err = newErrBatchCorrupted(fmt.Sprintf("invalid records length: %d vs %d", batchLen, decodedLen))
	}
	return
}

func (b *Batch) revertMemReplay(to *memdb.DB) error {
	var ikScratch []byte
	return b.decodeRec(func(i int, kt keyType, key, value []byte) error {
		ikScratch := makeInternalKey(ikScratch, key, b.seq+uint64(i), kt)
		return to.Delete(ikScratch)
	})
}

func (b *Batch) memReplay(to *memdb.DB) error {
	var ikScratch []byte
	return b.decodeRec(func(i int, kt kType, key, value []byte) error {
		ikScratch = makeIkey(ikScratch, key, b.seq+uint64(i), kt)
		return to.Put(ikScratch, value)
	})
}

func (d *DB) memCompaction(mem *memdb.DB) {
	s := d.s
	c := newCMem(s)
	stats := new(cStatsStaging)

	s.printf("MemCompaction: started, size=%d entries=%d", mem.Size(), mem.Len())

	d.transact(func() (err error) {
		stats.startTimer()
		defer stats.stopTimer()
		return c.flush(mem, -1)
	})

	d.transact(func() (err error) {
		stats.startTimer()
		defer stats.stopTimer()
		return c.commit(d.journal.file.Num(), d.fseq)
	})

	stats.write = c.t.size
	d.cstats[c.level].add(stats)

	// drop frozen mem
	d.dropFrozenMem()

	c = nil
}

func (b *Batch) revertMem(seq uint64, mdb *memdb.DB) error {
	var ik []byte
	for i, index := range b.index {
		ik = makeInternalKey(ik, index.k(b.data), seq+uint64(i), index.keyType)
		if err := mdb.Delete(ik); err != nil {
			return err
		}
	}
	return nil
}

func (db *DB) mpoolGet(n int) *memDB {
	var mdb *memdb.DB
	select {
	case mdb = <-db.memPool:
	default:
	}
	if mdb == nil || mdb.Capacity() < n {
		mdb = memdb.New(db.s.icmp, maxInt(db.s.o.GetWriteBuffer(), n))
	}
	return &memDB{
		db: db,
		DB: mdb,
	}
}

func (s *session) flushMemdb(rec *sessionRecord, mdb *memdb.DB, level int) (level_ int, err error) {
	// Create sorted table.
	iter := mdb.NewIterator(nil)
	defer iter.Release()
	t, n, err := s.tops.createFrom(iter)
	if err != nil {
		return level, err
	}

	// Pick level and add to record.
	if level < 0 {
		level = s.pickMemdbLevel(t.imin.ukey(), t.imax.ukey())
	}
	rec.addTableFile(level, t)

	s.logf("[email protected] created L%[email protected]%d N·%d S·%s %q:%q", level, t.file.Num(), n, shortenb(int(t.size)), t.imin, t.imax)
	return level, nil
}

func (c *cMem) flush(mem *memdb.DB, level int) error {
	s := c.s

	// Write memdb to table
	t, n, err := s.tops.createFrom(mem.NewIterator(nil))
	if err != nil {
		return err
	}

	if level < 0 {
		level = s.version_NB().pickLevel(t.min.ukey(), t.max.ukey())
	}
	c.rec.addTableFile(level, t)

	s.logf("[email protected] created L%[email protected]%d N·%d S·%s %q:%q", level, t.file.Num(), n, shortenb(int(t.size)), t.min, t.max)

	c.level = level
	return nil
}

func memGet(mdb *memdb.DB, ikey internalKey, icmp *iComparer) (ok bool, mv []byte, err error) {
	mk, mv, err := mdb.Find(ikey)
	if err == nil {
		ukey, _, kt, kerr := parseInternalKey(mk)
		if kerr != nil {
			// Shouldn't have had happen.
			panic(kerr)
		}
		if icmp.uCompare(ukey, ikey.ukey()) == 0 {
			if kt == keyTypeDel {
				return true, nil, ErrNotFound
			}
			return true, mv, nil

		}
	} else if err != ErrNotFound {
		return true, nil, err
	}
	return
}

func (c *cMem) flush(mem *memdb.DB, level int) error {
	s := c.s

	// Write memdb to table
	t, n, err := s.tops.createFrom(mem.NewIterator())
	if err != nil {
		return err
	}

	if level < 0 {
		level = s.version().pickLevel(t.min.ukey(), t.max.ukey())
	}
	c.rec.addTableFile(level, t)

	s.printf("Compaction: table created, source=mem level=%d num=%d size=%d entries=%d min=%q max=%q",
		level, t.file.Num(), t.size, n, t.min, t.max)

	c.level = level
	c.t = t
	return nil
}

func (s *session) flushMemdb(rec *sessionRecord, mdb *memdb.DB, maxLevel int) (int, error) {
	// Create sorted table.
	iter := mdb.NewIterator(nil)
	defer iter.Release()
	t, n, err := s.tops.createFrom(iter)
	if err != nil {
		return 0, err
	}

	// Pick level other than zero can cause compaction issue with large
	// bulk insert and delete on strictly incrementing key-space. The
	// problem is that the small deletion markers trapped at lower level,
	// while key/value entries keep growing at higher level. Since the
	// key-space is strictly incrementing it will not overlaps with
	// higher level, thus maximum possible level is always picked, while
	// overlapping deletion marker pushed into lower level.
	// See: https://github.com/syndtr/goleveldb/issues/127.
	flushLevel := s.pickMemdbLevel(t.imin.ukey(), t.imax.ukey(), maxLevel)
	rec.addTableFile(flushLevel, t)

	s.logf("[email protected] created L%[email protected]%d N·%d S·%s %q:%q", flushLevel, t.fd.Num, n, shortenb(int(t.size)), t.imin, t.imax)
	return flushLevel, nil
}

func (c *cMem) flush(mem *memdb.DB, level int) error {
	s := c.s

	// Write memdb to table.
	iter := mem.NewIterator(nil)
	defer iter.Release()
	t, n, err := s.tops.createFrom(iter)
	if err != nil {
		return err
	}

	// Pick level.
	if level < 0 {
		v := s.version()
		level = v.pickLevel(t.imin.ukey(), t.imax.ukey())
		v.release()
	}
	c.rec.addTableFile(level, t)

	s.logf("[email protected] created L%[email protected]%d N·%d S·%s %q:%q", level, t.file.Num(), n, shortenb(int(t.size)), t.imin, t.imax)

	c.level = level
	return nil
}

func isMemOverlaps(icmp *iComparer, mem *memdb.DB, min, max []byte) bool {
	iter := mem.NewIterator(nil)
	defer iter.Release()
	return (max == nil || (iter.First() && icmp.uCompare(max, internalKey(iter.Key()).ukey()) >= 0)) &&
		(min == nil || (iter.Last() && icmp.uCompare(min, internalKey(iter.Key()).ukey()) <= 0))
}

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("[email protected] 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()
			}
//.........这里部分代码省略.........

func (d *DB) recoverJournal() (err error) {
	s := d.s
	icmp := s.cmp

	s.printf("JournalRecovery: started, min=%d", s.stJournalNum)

	var mem *memdb.DB
	batch := new(Batch)
	cm := newCMem(s)

	journals := files(s.getFiles(storage.TypeJournal))
	journals.sort()
	rJournals := make([]storage.File, 0, len(journals))
	for _, journal := range journals {
		if journal.Num() >= s.stJournalNum || journal.Num() == s.stPrevJournalNum {
			s.markFileNum(journal.Num())
			rJournals = append(rJournals, journal)
		}
	}

	var r, fr *journalReader
	for _, journal := range rJournals {
		s.printf("JournalRecovery: recovering, num=%d", journal.Num())

		r, err = newJournalReader(journal, true, s.journalDropFunc("journal", journal.Num()))
		if err != nil {
			return
		}

		if mem != nil {
			if mem.Len() > 0 {
				err = cm.flush(mem, 0)
				if err != nil {
					return
				}
			}

			err = cm.commit(r.file.Num(), d.seq)
			if err != nil {
				return
			}

			cm.reset()

			fr.remove()
			fr = nil
		}

		mem = memdb.New(icmp)

		for r.journal.Next() {
			err = batch.decode(r.journal.Record())
			if err != nil {
				return
			}

			err = batch.memReplay(mem)
			if err != nil {
				return
			}

			d.seq = batch.seq + uint64(batch.len())

			if mem.Size() > s.o.GetWriteBuffer() {
				// flush to table
				err = cm.flush(mem, 0)
				if err != nil {
					return
				}

				// create new memdb
				mem = memdb.New(icmp)
			}
		}

		err = r.journal.Error()
		if err != nil {
			return
		}

		r.close()
		fr = r
	}

	// create new journal
	_, err = d.newMem()
	if err != nil {
		return
	}

	if mem != nil && mem.Len() > 0 {
		err = cm.flush(mem, 0)
		if err != nil {
			return
		}
	}

	err = cm.commit(d.journal.file.Num(), d.seq)
	if err != nil {
		return
//.........这里部分代码省略.........