github.com/m3db/m3@v1.5.0/src/dbnode/storage/block/retriever_manager.go (about)

     1  // Copyright (c) 2016 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package block
    22  
    23  import (
    24  	"sync"
    25  
    26  	"github.com/m3db/m3/src/dbnode/namespace"
    27  	"github.com/m3db/m3/src/dbnode/sharding"
    28  	"github.com/m3db/m3/src/dbnode/x/xio"
    29  	"github.com/m3db/m3/src/x/context"
    30  	"github.com/m3db/m3/src/x/ident"
    31  	xtime "github.com/m3db/m3/src/x/time"
    32  )
    33  
    34  // NewDatabaseBlockRetrieverFn is a method for constructing
    35  // new database block retrievers
    36  type NewDatabaseBlockRetrieverFn func(
    37  	md namespace.Metadata,
    38  	shardSet sharding.ShardSet,
    39  ) (DatabaseBlockRetriever, error)
    40  
    41  // NewDatabaseBlockRetrieverManager creates a new manager
    42  // for constructing and providing existing database block retrievers
    43  func NewDatabaseBlockRetrieverManager(
    44  	newDatabaseBlockRetrieverFn NewDatabaseBlockRetrieverFn,
    45  ) DatabaseBlockRetrieverManager {
    46  	return &blockRetrieverManager{
    47  		newRetrieverFn: newDatabaseBlockRetrieverFn,
    48  		retrievers:     newRetrieverMap(retrieverMapOptions{}),
    49  	}
    50  }
    51  
    52  type blockRetrieverManager struct {
    53  	sync.RWMutex
    54  	newRetrieverFn NewDatabaseBlockRetrieverFn
    55  	retrievers     *retrieverMap
    56  }
    57  
    58  func (m *blockRetrieverManager) Retriever(
    59  	md namespace.Metadata,
    60  	shardSet sharding.ShardSet,
    61  ) (DatabaseBlockRetriever, error) {
    62  	m.RLock()
    63  	retriever, ok := m.retrievers.Get(md.ID())
    64  	m.RUnlock()
    65  	if ok {
    66  		return retriever, nil
    67  	}
    68  
    69  	m.Lock()
    70  	defer m.Unlock()
    71  
    72  	retriever, ok = m.retrievers.Get(md.ID())
    73  	if ok {
    74  		return retriever, nil
    75  	}
    76  
    77  	var err error
    78  	retriever, err = m.newRetrieverFn(md, shardSet)
    79  	if err != nil {
    80  		return nil, err
    81  	}
    82  
    83  	m.retrievers.Set(md.ID(), retriever)
    84  	return retriever, nil
    85  }
    86  
    87  type shardBlockRetriever struct {
    88  	DatabaseBlockRetriever
    89  	shard uint32
    90  }
    91  
    92  // NewDatabaseShardBlockRetriever creates a new shard database
    93  // block retriever given an existing database block retriever
    94  func NewDatabaseShardBlockRetriever(
    95  	shard uint32,
    96  	r DatabaseBlockRetriever,
    97  ) DatabaseShardBlockRetriever {
    98  	return &shardBlockRetriever{
    99  		DatabaseBlockRetriever: r,
   100  		shard:                  shard,
   101  	}
   102  }
   103  
   104  func (r *shardBlockRetriever) Stream(
   105  	ctx context.Context,
   106  	id ident.ID,
   107  	blockStart xtime.UnixNano,
   108  	onRetrieve OnRetrieveBlock,
   109  	nsCtx namespace.Context,
   110  ) (xio.BlockReader, error) {
   111  	return r.DatabaseBlockRetriever.Stream(ctx, r.shard, id,
   112  		blockStart, onRetrieve, nsCtx)
   113  }
   114  
   115  type shardBlockRetrieverManager struct {
   116  	sync.RWMutex
   117  	retriever       DatabaseBlockRetriever
   118  	shardRetrievers map[uint32]DatabaseShardBlockRetriever
   119  }
   120  
   121  // NewDatabaseShardBlockRetrieverManager creates and holds shard block
   122  // retrievers binding shards to an existing retriever.
   123  func NewDatabaseShardBlockRetrieverManager(
   124  	r DatabaseBlockRetriever,
   125  ) DatabaseShardBlockRetrieverManager {
   126  	return &shardBlockRetrieverManager{
   127  		retriever:       r,
   128  		shardRetrievers: make(map[uint32]DatabaseShardBlockRetriever),
   129  	}
   130  }
   131  
   132  func (m *shardBlockRetrieverManager) ShardRetriever(
   133  	shard uint32,
   134  ) DatabaseShardBlockRetriever {
   135  	m.RLock()
   136  	retriever, ok := m.shardRetrievers[shard]
   137  	m.RUnlock()
   138  
   139  	if ok {
   140  		return retriever
   141  	}
   142  
   143  	m.Lock()
   144  	defer m.Unlock()
   145  
   146  	retriever, ok = m.shardRetrievers[shard]
   147  	if ok {
   148  		return retriever
   149  	}
   150  
   151  	retriever = NewDatabaseShardBlockRetriever(shard, m.retriever)
   152  	m.shardRetrievers[shard] = retriever
   153  	return retriever
   154  }