Orca API Reference

The Orca platform is a real-time computing framework built on DolphinDB's streaming infrastructure. It provides declarative APIs that abstract away low-level complexities (e.g., parallel scheduling, subscription mechanisms, and resource management), allowing developers to focus on business logic.

Category Interface Description
Definition createStreamGraph Create a StreamGraph object
StreamGraph::setConfigMap Configure private stream tables and subscriptions in the graph
StreamGraph::source / keyedSource / latestKeyedSource / haSource / haKeyedSource Define an input source stream table
StreamGraph::sourceByName Retrieve an Orca public stream table
DStream::anomalyDetectionEngine Define an anomaly detection engine
DStream::asofJoinEngine Define an asof join engine
DStream::crossSectionalEngine Define a cross-sectional engine
DStream::cryptoOrderBookEngine Define a real-time crypto order book engine
DStream::dailyTimeSeriesEngine Define a daily time-series engine
DStream::dualOwnershipReactiveStateEngine Define a dual-ownership reactive state engine
DStream::narrowReactiveStateEngine Define a reactive state engine that outputs narrow tables
DStream::pricingEngine Define a pricing engine
DStream::reactiveStateEngine Define a reactive state engine
DStream::reactiveStatelessEngine Define a reactive stateless engine
DStream::ruleEngine Define a rule engine
DStream::sessionWindowEngine Define a session window engine
DStream::timeBucketEngine Define a time series aggregation engine with custom bucket sizes
DStream::timeSeriesEngine Define a time series aggregation engine
DStream::equalJoinEngine Define an equi join engine
DStream::leftSemiJoinEngine Define a left semi join engine
DStream::lookupJoinEngine Define a lookup join engine
DStream::snapshotJoinEngine Define a snapshot join engine
DStream::windowJoinEngine Define a window join engine
DStream::buffer / keyedBuffer / latestKeyedBuffer Define a stream table for immediate output
DStream::sink / keyedSink / latestKeySink / haSink / haKeyedSink Define an output stream table
DStream::map Define data transformation logic
DStream::udfEngine Define a user-defined function that supports side effects and state persistence
DStream::fork Branch the stream graph
DStream::parallelize Set the parallelism of the stream graph
DStream::sync Aggregate the results of upstream parallel tasks
DStream::setEngineName Set name for a streaming engine
DStream::getOutputSchema Retrieve the table schema for downstream definition
Graph Management StreamGraph::submit Submit the stream graph to start execution
getStreamGraph Retrieve the stream graph object
dropStreamGraph Destroy the stream graph
purgeStreamGraphRecords Delete stream graph records
startStreamGraph / stopStreamGraph Start / suspend the stream graph
Stream Table Operations appendOrcaStreamTable Insert data into stream tables
useOrcaStreamTable Operate on the specified stream table from a remote node
select * from orca_table. or select * from .orca_table. Query a stream table
Streaming Engine Operations warmupOrcaStreamEngine Warm up streaming engine to improve initial computation performance
useOrcaStreamEngine Operate on the specified streaming engine from a remote node
Status Monitoring getStreamGraphInfo / getStreamGraphMeta Retrieve stream graph metadata
getOrcaStreamTableMeta Retrieve stream table metadata
getOrcaStreamEngineMeta Retrieve streaming engine metadata
getOrcaStreamTaskSubscriptionMeta Retrieve subscription metadata
getOrcaStateMachineEventTaskStatus Get state machine task status
StreamGraph::toGraphviz / str Output the topology structure
getUdfEngineVariable Query the current value of a specified external variable in a given DStream::udfEngine
Checkpoint Management setOrcaCheckpointConfig Configure checkpoint parameters
getOrcaCheckpointConfig View checkpoint configuration
getOrcaCheckpointJobInfo View checkpoint job execution info
getOrcaCheckpointSubjobInfo View checkpoint subjob execution info