h2database源码浅析：TransactionMap、MVMap、MVStore

• TransactionStore：A store that supports concurrent MVCC read-committed transactions.
• TransactionStore.Transaction：A transaction.
• TransactionStore.TransactionMap<K,V>：A map that supports transactions.

TransactionStore通过openMap获取到Map：

<K,V> TransactionStore.TransactionMap<K,V>
openMap(java.lang.String name, DataType keyType, DataType valueType) 
          Open the map to store the data.

TransactionStore通过open创建一个Transaction：
TransactionStore.Transaction begin() 
Begin a new transaction.

MVMap<K,V>

多版本Map
读操作：Read operations can happen concurrently with all other operations, without risk of corruption.
写操作：Write operations first read the relevant area from disk to memory concurrently, and only then modify the data. The in-memory part of write operations is synchronized. For scalable concurrent in-memory write operations, the map should be split into multiple smaller sub-maps that are then synchronized independently.

所有已实现的接口：
java.util.concurrent.ConcurrentMap<K,V>, java.util.Map<K,V>

直接已知子类：
MVMapConcurrent, MVRTreeMap

MVTableEngine.Store

public MVStore getStore() 获取MVStore

MVStore

A persistent storage for maps.
openMap()方法用以创建一个MVMap：

public <K,V> MVMap<K,V> openMap(java.lang.String name)