Haven't tested. Which error are you getting?

Just tried on IRIS 2020.3 and it works.

Try this

Class test.SQL
{

ClassMethod GetMsg(length As %Integer) As %Stream.TmpCharacter [ SqlProc ]
{
    Set stream = ##class(%Stream.TmpCharacter).%New()
    Set chunkLength = 32000
    Set chunk = $tr($j("", chunkLength)," ", "A")
    
    If length>=chunkLength {
        For i=1:chunkLength:length {
            Do stream.Write(chunk)
        }
    }
    
    Set tailLength = length#chunkLength
    Do:tailLength>0 stream.Write($e(chunk, 1, tailLength))
    
    Set sc = stream.%Save()

    Quit stream  //."%%OID" <- also works for persisted streams
}
}

Worked for me with this SQL (in SMP):

SELECT test.SQL_GetMsg(10), test.SQL_GetMsg(1)
UNION
SELECT test.SQL_GetMsg(10), test.SQL_GetMsg(2)  

Here's how you can have a bidirectional XML<>JSON converter:

1. If you do not have the class for your XML, create it from XSD or manually. Also  enable JSON for it.
2. Convert your XML string into an object of class (1).
3. Export JSON from your object.

Check the docs.

in most cases you'll need to run irisinstall.

i.e. do not place propertynames under quote

Property Arrival Time has a whitespace in the name so it must be quoted.

Why?

Your solution seems to work

As it looks like a security issue I would recommend a slightly different approach.

1. If you do not have the class for your XML, create it from XSD or manually.

2. Convert your XML string into an object of class (1).

3A. If you  want just to skip some properties (like RollNo) set availability of these projected properties to IN - this way property is used by import but is ignored on export. Alternatively disable projection of this property altogether.

3B. If you really want to return *** from your value (what's the use case?) add a new datatype test.PrivateString and use it to store RollNo value - during OBJ->XML projection it would be exported as ***.

Class test.PrivateString Extends %String
{

/// Declares the XSD type used when projecting XML Schemas.
Parameter XSDTYPE = "string";

/// Return "***"
ClassMethod LogicalToXSD(%val As %TimeStamp) As %String [ CodeMode = generator, ServerOnly = 1 ]
{
    If ($$$getClassType(%class)=$$$cCLASSCLASSTYPEDATATYPE) || $$$comMemberKeyGet(%class,$$$cCLASSparameter,"XMLENABLED",$$$cPARAMdefault) {
        Set %codemode=$$$cMETHCODEMODEEXPRESSION
        Set %code="""***"""
    } Else {
        Set %code=0
    }
    Quit $$$OK
}

}

Awesome!

Use  custom queries or global mapping.

Check EnsLogViewer - InterSystems IRIS/Ensemble Log Viewer with namespace support.

I think you'll need 2 separate indices for that.

Path is how you access the value.

Contact your Account Manager at InterSystems.

Check this post.

Usually I do this:

set sc = ..method()
/// finalization
quit:$$$ISERR(sc) sc

I always use %Status and try to wrap calls in this macro:

#define qoe(%expr) $$$QuitOnError(%expr)

For example:

$$$qoe(..computeDigest(canonicalized))

$$$ERROR($$$SQLError, SQLCODE, %msg)

You can use PythonGateway to call Python code from InterSystems IRIS directly.

Example:

set sc = ##class(isc.py.Main).SimpleString("x='HELLO'", "x", , .x)
write x
>HELLO

You can start with

set %gw = createJavaGateway()

Where createJavaGateway is

ClassMethod createJavaGateway()
{
  quit:$d(%gw) %gw
  /// init connection
}

And remove disconnect part. This way %gw variable would stay alive betwee the calls.