d17efaa114
* Fix bug on migration 111 * Upgrade bleve to 1.0.10 Co-authored-by: zeripath <art27@cantab.net> Co-authored-by: techknowlogick <techknowlogick@gitea.io>
213 lines
5.1 KiB
Go
Vendored
213 lines
5.1 KiB
Go
Vendored
// Copyright (c) 2017 Couchbase, Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package scorch
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import (
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"fmt"
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"log"
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"os"
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"github.com/blevesearch/bleve/index/scorch/segment"
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bolt "go.etcd.io/bbolt"
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)
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type RollbackPoint struct {
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epoch uint64
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meta map[string][]byte
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}
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func (r *RollbackPoint) GetInternal(key []byte) []byte {
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return r.meta[string(key)]
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}
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// RollbackPoints returns an array of rollback points available for
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// the application to rollback to, with more recent rollback points
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// (higher epochs) coming first.
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func RollbackPoints(path string) ([]*RollbackPoint, error) {
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if len(path) == 0 {
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return nil, fmt.Errorf("RollbackPoints: invalid path")
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}
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rootBoltPath := path + string(os.PathSeparator) + "root.bolt"
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rootBoltOpt := &bolt.Options{
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ReadOnly: true,
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}
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rootBolt, err := bolt.Open(rootBoltPath, 0600, rootBoltOpt)
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if err != nil || rootBolt == nil {
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return nil, err
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}
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// start a read-only bolt transaction
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tx, err := rootBolt.Begin(false)
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if err != nil {
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return nil, fmt.Errorf("RollbackPoints: failed to start" +
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" read-only transaction")
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}
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// read-only bolt transactions to be rolled back
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defer func() {
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_ = tx.Rollback()
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_ = rootBolt.Close()
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}()
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snapshots := tx.Bucket(boltSnapshotsBucket)
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if snapshots == nil {
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return nil, nil
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}
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rollbackPoints := []*RollbackPoint{}
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c1 := snapshots.Cursor()
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for k, _ := c1.Last(); k != nil; k, _ = c1.Prev() {
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_, snapshotEpoch, err := segment.DecodeUvarintAscending(k)
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if err != nil {
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log.Printf("RollbackPoints:"+
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" unable to parse segment epoch %x, continuing", k)
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continue
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}
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snapshot := snapshots.Bucket(k)
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if snapshot == nil {
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log.Printf("RollbackPoints:"+
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" snapshot key, but bucket missing %x, continuing", k)
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continue
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}
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meta := map[string][]byte{}
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c2 := snapshot.Cursor()
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for j, _ := c2.First(); j != nil; j, _ = c2.Next() {
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if j[0] == boltInternalKey[0] {
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internalBucket := snapshot.Bucket(j)
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err = internalBucket.ForEach(func(key []byte, val []byte) error {
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copiedVal := append([]byte(nil), val...)
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meta[string(key)] = copiedVal
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return nil
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})
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if err != nil {
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break
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}
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}
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}
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if err != nil {
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log.Printf("RollbackPoints:"+
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" failed in fetching internal data: %v", err)
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continue
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}
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rollbackPoints = append(rollbackPoints, &RollbackPoint{
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epoch: snapshotEpoch,
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meta: meta,
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})
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}
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return rollbackPoints, nil
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}
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// Rollback atomically and durably brings the store back to the point
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// in time as represented by the RollbackPoint.
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// Rollback() should only be passed a RollbackPoint that came from the
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// same store using the RollbackPoints() API along with the index path.
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func Rollback(path string, to *RollbackPoint) error {
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if to == nil {
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return fmt.Errorf("Rollback: RollbackPoint is nil")
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}
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if len(path) == 0 {
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return fmt.Errorf("Rollback: index path is empty")
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}
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rootBoltPath := path + string(os.PathSeparator) + "root.bolt"
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rootBoltOpt := &bolt.Options{
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ReadOnly: false,
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}
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rootBolt, err := bolt.Open(rootBoltPath, 0600, rootBoltOpt)
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if err != nil || rootBolt == nil {
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return err
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}
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defer func() {
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err1 := rootBolt.Close()
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if err1 != nil && err == nil {
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err = err1
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}
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}()
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// pick all the younger persisted epochs in bolt store
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// including the target one.
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var found bool
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var eligibleEpochs []uint64
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err = rootBolt.View(func(tx *bolt.Tx) error {
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snapshots := tx.Bucket(boltSnapshotsBucket)
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if snapshots == nil {
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return nil
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}
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sc := snapshots.Cursor()
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for sk, _ := sc.Last(); sk != nil && !found; sk, _ = sc.Prev() {
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_, snapshotEpoch, err := segment.DecodeUvarintAscending(sk)
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if err != nil {
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continue
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}
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if snapshotEpoch == to.epoch {
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found = true
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}
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eligibleEpochs = append(eligibleEpochs, snapshotEpoch)
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}
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return nil
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})
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if len(eligibleEpochs) == 0 {
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return fmt.Errorf("Rollback: no persisted epochs found in bolt")
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}
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if !found {
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return fmt.Errorf("Rollback: target epoch %d not found in bolt", to.epoch)
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}
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// start a write transaction
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tx, err := rootBolt.Begin(true)
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if err != nil {
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return err
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}
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defer func() {
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if err == nil {
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err = tx.Commit()
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} else {
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_ = tx.Rollback()
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}
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if err == nil {
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err = rootBolt.Sync()
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}
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}()
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snapshots := tx.Bucket(boltSnapshotsBucket)
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if snapshots == nil {
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return nil
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}
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for _, epoch := range eligibleEpochs {
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k := segment.EncodeUvarintAscending(nil, epoch)
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if err != nil {
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continue
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}
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if epoch == to.epoch {
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// return here as it already processed until the given epoch
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return nil
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}
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err = snapshots.DeleteBucket(k)
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if err == bolt.ErrBucketNotFound {
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err = nil
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}
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}
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return err
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}
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