StateStore¶

StateStore is an abstraction of storage engines (for the state of a stream processor).

Contract¶

Closing¶

void close()

Flushing Cached Data¶

void flush()

Flushing cached data of this StateStore

Used when:

• GlobalStateManagerImpl is requested to flush all global state stores
• ProcessorStateManager is requested to flush all state stores and flushCache

Initializing¶

void init(
  StateStoreContext context,
  StateStore root)

isOpen¶

boolean isOpen()

Name¶

String name()

persistent¶

boolean persistent()

Used when:

• GlobalStateManagerImpl is created (and finds global non-persistent state stores)
• ProcessorStateManager is requested to initializeStoreOffsetsFromCheckpoint and checkpoint
• ProcessorTopology is requested to hasPersistentLocalStore and hasPersistentGlobalStore
• TimestampedKeyValueStoreBuilder is requested to build a TimestampedKeyValueStore
• TimestampedWindowStoreBuilder is requested to build a TimestampedWindowStore
• others

Implementations¶

• KeyValueStore
• SegmentedBytesStore
• SessionStore
• TimeOrderedKeyValueBuffer
• WindowStore
• WrappedStateStore