github.com/vescale/zgraph@v0.0.0-20230410094002-959c02d50f95/storage/resolver/scheduler.go (about)

     1  // Copyright 2022 zGraph Authors. All rights reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package resolver
    16  
    17  import (
    18  	"context"
    19  	"sync"
    20  	"sync/atomic"
    21  
    22  	"github.com/cockroachdb/pebble"
    23  	"github.com/sourcegraph/conc"
    24  	"github.com/twmb/murmur3"
    25  	"github.com/vescale/zgraph/storage/kv"
    26  )
    27  
    28  // Scheduler is used to schedule Resolve tasks.
    29  type Scheduler struct {
    30  	running   atomic.Bool
    31  	mu        sync.Mutex
    32  	db        *pebble.DB
    33  	size      int
    34  	resolvers []*resolver
    35  	wg        conc.WaitGroup
    36  	cancelFn  context.CancelFunc
    37  }
    38  
    39  func NewScheduler(size int) *Scheduler {
    40  	s := &Scheduler{
    41  		size: size,
    42  	}
    43  	return s
    44  }
    45  
    46  func (s *Scheduler) SetDB(db *pebble.DB) {
    47  	s.mu.Lock()
    48  	defer s.mu.Unlock()
    49  	s.db = db
    50  }
    51  
    52  // Run initializes the resolvers and start to accept resolve tasks.
    53  func (s *Scheduler) Run() {
    54  	if s.running.Swap(true) {
    55  		return
    56  	}
    57  
    58  	ctx, cancelFn := context.WithCancel(context.Background())
    59  	for i := 0; i < s.size; i++ {
    60  		r := newResolver(s.db)
    61  		s.resolvers = append(s.resolvers, r)
    62  		s.wg.Go(func() { r.run(ctx) })
    63  	}
    64  	s.cancelFn = cancelFn
    65  }
    66  
    67  // Resolve submits a bundle of keys to resolve
    68  func (s *Scheduler) Resolve(keys []kv.Key, startVer, commitVer kv.Version, notifier Notifier) {
    69  	if len(keys) == 0 {
    70  		return
    71  	}
    72  	for _, key := range keys {
    73  		idx := int(murmur3.Sum32(key)) % s.size
    74  		s.resolvers[idx].push(Task{
    75  			Key:       key,
    76  			StartVer:  startVer,
    77  			CommitVer: commitVer,
    78  			Notifier:  notifier,
    79  		})
    80  	}
    81  }
    82  
    83  func (s *Scheduler) Close() {
    84  	s.cancelFn()
    85  	s.wg.Wait()
    86  	for _, r := range s.resolvers {
    87  		r.close()
    88  	}
    89  }