github.com/matrixorigin/matrixone@v0.7.0/pkg/fileservice/mem_cache.go (about)

     1  // Copyright 2022 Matrix Origin
     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 fileservice
    16  
    17  import (
    18  	"context"
    19  	"sync/atomic"
    20  
    21  	"github.com/matrixorigin/matrixone/pkg/util/trace"
    22  )
    23  
    24  type MemCache struct {
    25  	lru   *LRU
    26  	stats *CacheStats
    27  }
    28  
    29  func NewMemCache(capacity int64) *MemCache {
    30  	return &MemCache{
    31  		lru:   NewLRU(capacity),
    32  		stats: new(CacheStats),
    33  	}
    34  }
    35  
    36  var _ Cache = new(MemCache)
    37  
    38  func (m *MemCache) Read(
    39  	ctx context.Context,
    40  	vector *IOVector,
    41  ) (
    42  	err error,
    43  ) {
    44  	_, span := trace.Start(ctx, "MemCache.Read")
    45  	defer span.End()
    46  
    47  	numHit := 0
    48  	defer func() {
    49  		if m.stats != nil {
    50  			atomic.AddInt64(&m.stats.NumRead, int64(len(vector.Entries)))
    51  			atomic.AddInt64(&m.stats.NumHit, int64(numHit))
    52  		}
    53  	}()
    54  
    55  	for i, entry := range vector.Entries {
    56  		if entry.done {
    57  			continue
    58  		}
    59  		if entry.ToObject == nil {
    60  			continue
    61  		}
    62  		key := CacheKey{
    63  			Path:   vector.FilePath,
    64  			Offset: entry.Offset,
    65  			Size:   entry.Size,
    66  		}
    67  		obj, size, ok := m.lru.Get(key)
    68  		if ok {
    69  			vector.Entries[i].Object = obj
    70  			vector.Entries[i].ObjectSize = size
    71  			vector.Entries[i].done = true
    72  			numHit++
    73  		}
    74  	}
    75  
    76  	return
    77  }
    78  
    79  func (m *MemCache) Update(
    80  	ctx context.Context,
    81  	vector *IOVector,
    82  ) error {
    83  	for _, entry := range vector.Entries {
    84  		if entry.Object == nil {
    85  			continue
    86  		}
    87  		key := CacheKey{
    88  			Path:   vector.FilePath,
    89  			Offset: entry.Offset,
    90  			Size:   entry.Size,
    91  		}
    92  		m.lru.Set(key, entry.Object, entry.ObjectSize)
    93  	}
    94  	return nil
    95  }
    96  
    97  func (m *MemCache) Flush() {
    98  	m.lru.Flush()
    99  }
   100  
   101  func (m *MemCache) CacheStats() *CacheStats {
   102  	return m.stats
   103  }