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 |