419 lines
10 KiB
Go
419 lines
10 KiB
Go
// Copyright (c) 2017 Couchbase, Inc.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package zap
|
|
|
|
import (
|
|
"bytes"
|
|
"encoding/binary"
|
|
"fmt"
|
|
"io"
|
|
"os"
|
|
"sync"
|
|
|
|
"github.com/RoaringBitmap/roaring"
|
|
"github.com/Smerity/govarint"
|
|
"github.com/blevesearch/bleve/index/scorch/segment"
|
|
"github.com/couchbase/vellum"
|
|
mmap "github.com/edsrzf/mmap-go"
|
|
"github.com/golang/snappy"
|
|
)
|
|
|
|
// Open returns a zap impl of a segment
|
|
func Open(path string) (segment.Segment, error) {
|
|
f, err := os.Open(path)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
mm, err := mmap.Map(f, mmap.RDONLY, 0)
|
|
if err != nil {
|
|
// mmap failed, try to close the file
|
|
_ = f.Close()
|
|
return nil, err
|
|
}
|
|
|
|
rv := &Segment{
|
|
f: f,
|
|
mm: mm,
|
|
path: path,
|
|
fieldsMap: make(map[string]uint16),
|
|
fieldDvIterMap: make(map[uint16]*docValueIterator),
|
|
refs: 1,
|
|
}
|
|
|
|
err = rv.loadConfig()
|
|
if err != nil {
|
|
_ = rv.Close()
|
|
return nil, err
|
|
}
|
|
|
|
err = rv.loadFields()
|
|
if err != nil {
|
|
_ = rv.Close()
|
|
return nil, err
|
|
}
|
|
|
|
err = rv.loadDvIterators()
|
|
if err != nil {
|
|
_ = rv.Close()
|
|
return nil, err
|
|
}
|
|
|
|
return rv, nil
|
|
}
|
|
|
|
// Segment implements the segment.Segment inteface over top the zap file format
|
|
type Segment struct {
|
|
f *os.File
|
|
mm mmap.MMap
|
|
path string
|
|
crc uint32
|
|
version uint32
|
|
chunkFactor uint32
|
|
numDocs uint64
|
|
storedIndexOffset uint64
|
|
fieldsIndexOffset uint64
|
|
|
|
fieldsMap map[string]uint16
|
|
fieldsInv []string
|
|
fieldsOffsets []uint64
|
|
|
|
docValueOffset uint64
|
|
fieldDvIterMap map[uint16]*docValueIterator // naive chunk cache per field
|
|
|
|
m sync.Mutex // Protects the fields that follow.
|
|
refs int64
|
|
}
|
|
|
|
func (s *Segment) SizeInBytes() uint64 {
|
|
// 4 /* size of crc -> uint32 */ +
|
|
// 4 /* size of version -> uint32 */ +
|
|
// 4 /* size of chunkFactor -> uint32 */ +
|
|
// 8 /* size of numDocs -> uint64 */ +
|
|
// 8 /* size of storedIndexOffset -> uint64 */ +
|
|
// 8 /* size of fieldsIndexOffset -> uint64 */
|
|
sizeOfUints := 36
|
|
|
|
sizeInBytes := len(s.mm) + len(s.path) + sizeOfUints
|
|
|
|
for k, _ := range s.fieldsMap {
|
|
sizeInBytes += len(k) + 2 /* size of uint16 */
|
|
}
|
|
|
|
for _, entry := range s.fieldsInv {
|
|
sizeInBytes += len(entry)
|
|
}
|
|
|
|
sizeInBytes += len(s.fieldsOffsets) * 8 /* size of uint64 */
|
|
sizeInBytes += 8 /* size of refs -> int64 */
|
|
|
|
return uint64(sizeInBytes)
|
|
}
|
|
|
|
func (s *Segment) AddRef() {
|
|
s.m.Lock()
|
|
s.refs++
|
|
s.m.Unlock()
|
|
}
|
|
|
|
func (s *Segment) DecRef() (err error) {
|
|
s.m.Lock()
|
|
s.refs--
|
|
if s.refs == 0 {
|
|
err = s.closeActual()
|
|
}
|
|
s.m.Unlock()
|
|
return err
|
|
}
|
|
|
|
func (s *Segment) loadConfig() error {
|
|
crcOffset := len(s.mm) - 4
|
|
s.crc = binary.BigEndian.Uint32(s.mm[crcOffset : crcOffset+4])
|
|
verOffset := crcOffset - 4
|
|
s.version = binary.BigEndian.Uint32(s.mm[verOffset : verOffset+4])
|
|
if s.version != version {
|
|
return fmt.Errorf("unsupported version %d", s.version)
|
|
}
|
|
chunkOffset := verOffset - 4
|
|
s.chunkFactor = binary.BigEndian.Uint32(s.mm[chunkOffset : chunkOffset+4])
|
|
|
|
docValueOffset := chunkOffset - 8
|
|
s.docValueOffset = binary.BigEndian.Uint64(s.mm[docValueOffset : docValueOffset+8])
|
|
fieldsOffset := docValueOffset - 8
|
|
|
|
s.fieldsIndexOffset = binary.BigEndian.Uint64(s.mm[fieldsOffset : fieldsOffset+8])
|
|
storedOffset := fieldsOffset - 8
|
|
s.storedIndexOffset = binary.BigEndian.Uint64(s.mm[storedOffset : storedOffset+8])
|
|
docNumOffset := storedOffset - 8
|
|
s.numDocs = binary.BigEndian.Uint64(s.mm[docNumOffset : docNumOffset+8])
|
|
return nil
|
|
|
|
}
|
|
|
|
func (s *Segment) loadFields() error {
|
|
// NOTE for now we assume the fields index immediately preceeds the footer
|
|
// if this changes, need to adjust accordingly (or store epxlicit length)
|
|
fieldsIndexEnd := uint64(len(s.mm) - FooterSize)
|
|
|
|
// iterate through fields index
|
|
var fieldID uint64
|
|
for s.fieldsIndexOffset+(8*fieldID) < fieldsIndexEnd {
|
|
addr := binary.BigEndian.Uint64(s.mm[s.fieldsIndexOffset+(8*fieldID) : s.fieldsIndexOffset+(8*fieldID)+8])
|
|
var n uint64
|
|
|
|
dictLoc, read := binary.Uvarint(s.mm[addr+n : fieldsIndexEnd])
|
|
n += uint64(read)
|
|
s.fieldsOffsets = append(s.fieldsOffsets, dictLoc)
|
|
|
|
var nameLen uint64
|
|
nameLen, read = binary.Uvarint(s.mm[addr+n : fieldsIndexEnd])
|
|
n += uint64(read)
|
|
|
|
name := string(s.mm[addr+n : addr+n+nameLen])
|
|
s.fieldsInv = append(s.fieldsInv, name)
|
|
s.fieldsMap[name] = uint16(fieldID + 1)
|
|
|
|
fieldID++
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Dictionary returns the term dictionary for the specified field
|
|
func (s *Segment) Dictionary(field string) (segment.TermDictionary, error) {
|
|
dict, err := s.dictionary(field)
|
|
if err == nil && dict == nil {
|
|
return &segment.EmptyDictionary{}, nil
|
|
}
|
|
return dict, err
|
|
}
|
|
|
|
func (s *Segment) dictionary(field string) (rv *Dictionary, err error) {
|
|
rv = &Dictionary{
|
|
segment: s,
|
|
field: field,
|
|
}
|
|
|
|
rv.fieldID = s.fieldsMap[field]
|
|
if rv.fieldID > 0 {
|
|
rv.fieldID = rv.fieldID - 1
|
|
|
|
dictStart := s.fieldsOffsets[rv.fieldID]
|
|
if dictStart > 0 {
|
|
// read the length of the vellum data
|
|
vellumLen, read := binary.Uvarint(s.mm[dictStart : dictStart+binary.MaxVarintLen64])
|
|
fstBytes := s.mm[dictStart+uint64(read) : dictStart+uint64(read)+vellumLen]
|
|
if fstBytes != nil {
|
|
rv.fst, err = vellum.Load(fstBytes)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("dictionary field %s vellum err: %v", field, err)
|
|
}
|
|
}
|
|
}
|
|
|
|
} else {
|
|
return nil, nil
|
|
}
|
|
|
|
return rv, nil
|
|
}
|
|
|
|
// VisitDocument invokes the DocFieldValueVistor for each stored field
|
|
// for the specified doc number
|
|
func (s *Segment) VisitDocument(num uint64, visitor segment.DocumentFieldValueVisitor) error {
|
|
// first make sure this is a valid number in this segment
|
|
if num < s.numDocs {
|
|
meta, compressed := s.getStoredMetaAndCompressed(num)
|
|
uncompressed, err := snappy.Decode(nil, compressed)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
// now decode meta and process
|
|
reader := bytes.NewReader(meta)
|
|
decoder := govarint.NewU64Base128Decoder(reader)
|
|
|
|
keepGoing := true
|
|
for keepGoing {
|
|
field, err := decoder.GetU64()
|
|
if err == io.EOF {
|
|
break
|
|
}
|
|
if err != nil {
|
|
return err
|
|
}
|
|
typ, err := decoder.GetU64()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
offset, err := decoder.GetU64()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
l, err := decoder.GetU64()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
numap, err := decoder.GetU64()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
var arrayPos []uint64
|
|
if numap > 0 {
|
|
arrayPos = make([]uint64, numap)
|
|
for i := 0; i < int(numap); i++ {
|
|
ap, err := decoder.GetU64()
|
|
if err != nil {
|
|
return err
|
|
}
|
|
arrayPos[i] = ap
|
|
}
|
|
}
|
|
|
|
value := uncompressed[offset : offset+l]
|
|
keepGoing = visitor(s.fieldsInv[field], byte(typ), value, arrayPos)
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Count returns the number of documents in this segment.
|
|
func (s *Segment) Count() uint64 {
|
|
return s.numDocs
|
|
}
|
|
|
|
// DocNumbers returns a bitset corresponding to the doc numbers of all the
|
|
// provided _id strings
|
|
func (s *Segment) DocNumbers(ids []string) (*roaring.Bitmap, error) {
|
|
rv := roaring.New()
|
|
|
|
if len(s.fieldsMap) > 0 {
|
|
idDict, err := s.dictionary("_id")
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
for _, id := range ids {
|
|
postings, err := idDict.postingsList(id, nil)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if postings.postings != nil {
|
|
rv.Or(postings.postings)
|
|
}
|
|
}
|
|
}
|
|
|
|
return rv, nil
|
|
}
|
|
|
|
// Fields returns the field names used in this segment
|
|
func (s *Segment) Fields() []string {
|
|
return s.fieldsInv
|
|
}
|
|
|
|
// Path returns the path of this segment on disk
|
|
func (s *Segment) Path() string {
|
|
return s.path
|
|
}
|
|
|
|
// Close releases all resources associated with this segment
|
|
func (s *Segment) Close() (err error) {
|
|
return s.DecRef()
|
|
}
|
|
|
|
func (s *Segment) closeActual() (err error) {
|
|
if s.mm != nil {
|
|
err = s.mm.Unmap()
|
|
}
|
|
// try to close file even if unmap failed
|
|
if s.f != nil {
|
|
err2 := s.f.Close()
|
|
if err == nil {
|
|
// try to return first error
|
|
err = err2
|
|
}
|
|
}
|
|
return
|
|
}
|
|
|
|
// some helpers i started adding for the command-line utility
|
|
|
|
// Data returns the underlying mmaped data slice
|
|
func (s *Segment) Data() []byte {
|
|
return s.mm
|
|
}
|
|
|
|
// CRC returns the CRC value stored in the file footer
|
|
func (s *Segment) CRC() uint32 {
|
|
return s.crc
|
|
}
|
|
|
|
// Version returns the file version in the file footer
|
|
func (s *Segment) Version() uint32 {
|
|
return s.version
|
|
}
|
|
|
|
// ChunkFactor returns the chunk factor in the file footer
|
|
func (s *Segment) ChunkFactor() uint32 {
|
|
return s.chunkFactor
|
|
}
|
|
|
|
// FieldsIndexOffset returns the fields index offset in the file footer
|
|
func (s *Segment) FieldsIndexOffset() uint64 {
|
|
return s.fieldsIndexOffset
|
|
}
|
|
|
|
// StoredIndexOffset returns the stored value index offset in the file footer
|
|
func (s *Segment) StoredIndexOffset() uint64 {
|
|
return s.storedIndexOffset
|
|
}
|
|
|
|
// DocValueOffset returns the docValue offset in the file footer
|
|
func (s *Segment) DocValueOffset() uint64 {
|
|
return s.docValueOffset
|
|
}
|
|
|
|
// NumDocs returns the number of documents in the file footer
|
|
func (s *Segment) NumDocs() uint64 {
|
|
return s.numDocs
|
|
}
|
|
|
|
// DictAddr is a helper function to compute the file offset where the
|
|
// dictionary is stored for the specified field.
|
|
func (s *Segment) DictAddr(field string) (uint64, error) {
|
|
var fieldID uint16
|
|
var ok bool
|
|
if fieldID, ok = s.fieldsMap[field]; !ok {
|
|
return 0, fmt.Errorf("no such field '%s'", field)
|
|
}
|
|
|
|
return s.fieldsOffsets[fieldID-1], nil
|
|
}
|
|
|
|
func (s *Segment) loadDvIterators() error {
|
|
if s.docValueOffset == fieldNotUninverted {
|
|
return nil
|
|
}
|
|
|
|
var read uint64
|
|
for fieldID, field := range s.fieldsInv {
|
|
fieldLoc, n := binary.Uvarint(s.mm[s.docValueOffset+read : s.docValueOffset+read+binary.MaxVarintLen64])
|
|
if n <= 0 {
|
|
return fmt.Errorf("loadDvIterators: failed to read the docvalue offsets for field %d", fieldID)
|
|
}
|
|
s.fieldDvIterMap[uint16(fieldID)], _ = s.loadFieldDocValueIterator(field, fieldLoc)
|
|
read += uint64(n)
|
|
}
|
|
return nil
|
|
}
|