useOrcaStreamEngine

useOrcaStreamEngine(name, func, args...)

This function locates the node where the specified orca stream engine is running, retrieves the stream engine object, and passes it as the first argument to the user-defined function func for execution.

This mechanism allows users to remotely invoke various stream engine operations from local machine, without needing to manually manage the bindings between nodes and stream engines.

name is a string representing the name of the streaming egine. You can provide either the fully qualified name (FQN), such as "catalog_name.orca_engine.engine_name", or just the engine name, like "engine_name". If only the name is given, the system will automatically complete it using the current catalog.

func is a function to be executed on the node where the stream engine resides. This function must take at least one parameter; the system will automatically pass the stream engine object as the first argument.

args... are additional arguments to be passed to func, similar to how arguments are passed in remote procedure calls (rpc).

Returns the result of executing the user-specified function func.

Check the status of the orca reactive state engine test.orca_engine.rse using the getStreamEngineStateTable function:

if (!existsCatalog("test")) {
	createCatalog("test")
}
go;
use catalog test

t = table(1..100 as id, 1..100 as value, take(09:29:00.000..13:00:00.000, 100) as timestamp)
g = createStreamGraph("factor")
baseStream = g.source("snapshot",  1024:0, schema(t).colDefs.name, schema(t).colDefs.typeString)
  .reactiveStateEngine([<ema(value, 100)>, <timestamp>])
  .setEngineName("rse")
  .buffer("end")
  
g.submit()
useOrcaStreamEngine("test.orca_engine.rse", getStreamEngineStateTable)

 /*
 value ema(value, 100) timestamp
----- --------------- ---------
*/

Related function: getOrcaStreamEngineMeta