Graph database_neo4j 底层存储结构分析(2)

3       neo4j存储结构

neo4j 中,主要有4类节点,属性,关系等文件是以数组作为核心存储结构;同时对节点,属性,关系等类型的每个数据项都会分配一个唯一的ID,在存储时以该ID 为数组的下标。这样,在访问时通过其ID作为下标,实现快速定位。所以在图遍历等操作时,可以实现 free-index。

3.1  neo4j 的 store 部分类图

neo4j-类图--store继承图

3.1.1   CommonAbstractStore.java

CommonAbstractStore 是所有 Store 类的基类,下面的代码片段是 CommonAbstractStore 的成员变量,比较重要的是飘红的几个,特别是IdGenerator,每种Store 的实例都有自己的 id 分配管理器; StoreChannel 是负责Store文件的读写和定位;WindowsPool 是与Store Record相关的缓存,用来提升性能的。

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</pre>
<div>public abstract class CommonAbstractStore implements IdSequence
 
{
 
public static abstract class Configuration
 
{
 
public static final Setting store_dir = InternalAbstractGraphDatabase.Configuration.store_dir;
 
public static final Setting neo_store = InternalAbstractGraphDatabase.Configuration.neo_store;
 
public static final Setting read_only = GraphDatabaseSettings.read_only;
 
public static final Setting backup_slave = GraphDatabaseSettings.backup_slave;
 
public static final Setting use_memory_mapped_buffers = GraphDatabaseSettings.use_memory_mapped_buffers;
 
}
 
public static final String ALL_STORES_VERSION = "v0.A.2";
 
public static final String UNKNOWN_VERSION = "Uknown";
 
protected Config configuration;
 
private final IdGeneratorFactory idGeneratorFactory;
 
private final WindowPoolFactory windowPoolFactory;
 
protected FileSystemAbstraction fileSystemAbstraction;
 
protected final File storageFileName;
 
protected final IdType idType;
 
protected StringLogger stringLogger;
 
private IdGenerator idGenerator = null;
 
private StoreChannel fileChannel = null;
 
private WindowPool windowPool;
 
private boolean storeOk = true;
 
private Throwable causeOfStoreNotOk;
 
private FileLock fileLock;
 
private boolean readOnly = false;
 
private boolean backupSlave = false;
 
private long highestUpdateRecordId = -1;

1.2  neo4j 的db文件及对应的存储格式类型

文件名 文件存储格式
neostore.labeltokenstore.db LabelTokenStore(TokenStore)
neostore.labeltokenstore.db.id ID 类型
neostore.labeltokenstore.db.names StringPropertyStore (AbstractDynamicStore, NAME_STORE_BLOCK_SIZE = 30)
neostore.labeltokenstore.db.names.id ID 类型
neostore.nodestore.db NodeStore
neostore.nodestore.db.id ID 类型
neostore.nodestore.db.labels ArrayPropertyStore (AbstractDynamicStorelabel_block_size=60)
neostore.nodestore.db.labels.id ID 类型
neostore.propertystore.db PropertyStore
neostore.propertystore.db.arrays ArrayPropertyStore (AbstractDynamicStorearray_block_size=120)
neostore.propertystore.db.arrays.id ID 类型
neostore.propertystore.db.id ID 类型
neostore.propertystore.db.index PropertyIndexStore
neostore.propertystore.db.index.id ID 类型
neostore.propertystore.db.index.keys StringPropertyStore (AbstractDynamicStore, NAME_STORE_BLOCK_SIZE = 30)
neostore.propertystore.db.index.keys.id ID 类型
neostore.propertystore.db.strings StringPropertyStore (AbstractDynamicStorestring_block_size=120)
neostore.propertystore.db.strings.id ID 类型
neostore.relationshipgroupstore.db RelationshipGroupStore
neostore.relationshipgroupstore.db.id ID 类型
neostore.relationshipstore.db RelationshipStore
neostore.relationshipstore.db.id ID 类型
neostore.relationshiptypestore.db RelationshipTypeTokenStore(TokenStore)
neostore.relationshiptypestore.db.id ID 类型
neostore.relationshiptypestore.db.names StringPropertyStore (AbstractDynamicStore, NAME_STORE_BLOCK_SIZE = 30)
 neostore.relationshiptypestore.db.names.id ID 类型
neostore.schemastore.db SchemaStore(AbstractDynamicStore, BLOCK_SIZE = 56)
neostore.schemastore.db.id ID 类型
posted @ 2015-06-02 10:38  GisClub  阅读(712)  评论(0编辑  收藏  举报