org.apache.storm.trident.state

Interface State

All Known Subinterfaces:

MapState<T>, ReadOnlyMapState<T>, ReadOnlySnapshottable<T>, RemovableMapState<T>, Snapshottable<T>

All Known Implementing Classes:

CassandraState, DebugMemoryMapState, HBaseState, HdfsState, HiveState, JdbcState, JmsState, LRUMemoryMapState, MemoryMapState, MongoState, NonTransactionalMap, OpaqueMap, OpenTsdbState, ReadOnlyState, RedisClusterState, RedisState, RocketMqState, SnapshottableMap, SolrState, TransactionalMap, TridentKafkaState, TridentReach.StaticSingleKeyMapState, WindowsState

public interface State

There’s 3 different kinds of state:

1. non-transactional: ignores commits, updates are permanent. no rollback. a cassandra incrementing state would be like this 2. repeat-transactional: idempotent as long as all batches for a txid are identical 3. opaque-transactional: the most general kind of state. updates are always done based on the previous version of the value if the current commit = latest stored commit Idempotent even if the batch for a txid can change.

repeat transactional is idempotent for transactional spouts opaque transactional is idempotent for opaque or transactional spouts

Trident should log warnings when state is idempotent but updates will not be idempotent because of spout

Method Summary

Modifier and Type	Method and Description
void	beginCommit(Long txid)
void	commit(Long txid)

Method Detail

beginCommit

void beginCommit(Long txid)

commit

void commit(Long txid)