Good answer. If I may add.

You can't use Output or ByRef arguments on these functions, or let me rather say that I have not gotten it to work.

What you can do is return a collection type property, or you can pass in the context as a parameter to set properties on the context.
If you are wondering how to reference a context in a ruleset, add a property to you context of type %RegisteredObject and call it something like RefToSelf. Set the property to the OREF of the context once the context has been created.
Then in the rulefunction call, you pass in RefToSelf.

Hi,

My 2c on this, and maybe I am missing something or do not know how to use these VSCode extensions correctly.
The single source of truth principle can't really be applied when using these extensions, as BPLs, transformations, and rulesets should still be edited in the Management Portal or in Studio.

Because there is not a sync functionality, I have seen devs overwriting changes on BPLs, etc., when they import and compile from VSCode. You have to explicitly export it on the server explorer.

Please correct me if I'm mistaking.

Try it with between 1 and 5 on the %VID. Just as slow. It is not about the 0 result, but about the time it takes.

The count on prop1=2 is around 2.7M/

Regarding the index:
Index idx On (prop1, prop3) [ Type = bitmap ];

I can't create an index on every possible filter and order by combination. The client selects what to filter on and what to order by.

We use single field indices to cater for this, and combined field indexes for uniqueness constraints. 

Let's change the data and then test it with an order by:
Prop1 is i %Integer with valuelist of 1 to 10. Populated randomly, with 60% of the values being 2.
Prop2 is can stay as is and not relevant in this test.
Prop3 is a %String of length 20. Populate with 4M random values.
Prop1 has a bitmap index.
Prop2 has a bitmap index.
Prop3 has an index.

To use order by, it needs to look like this, and this is a lot slower:
select %ID,prop3 
from mp.test 
where %ID in 
  (SELECT * FROM 
    (SELECT TOP ALL %ID
     FROM mp.test 
     WHERE prop1 = 2
     ORDER BY prop3
  
  WHERE %VID BETWEEN 3000000 AND 30000200
)

Class mp.test Extends (%Persistent, %Populate)
{

Property prop1 As %Integer(POPSPEC = ".PopulateProp1()", VALUELIST = ",1,2,3,4,5,6,7,8,9,10");

Property prop2 As %Boolean(POPSPEC = "Integer(0,1)");

Property prop3 As %String(MAXLEN = "", POPSPEC = "LastName()");

Index prop1Index On prop1 [ Type = bitmap ];

Index prop2Index On prop2 [ Type = bitmap ];

Index prop3Index On prop3;

ClassMethod Fill(total)
{
    ;d DISABLE^%NOJRN
    ;d ..%KillExtent()
    ;do ..Populate(5000000)
}

Method PopulateProp1() As %Integer
{
    set tInt = $random(19) + 1
    set:(tInt > 10) tInt = 2
    return tInt
}

ClassMethod Query()
{
    s sql=##class(%SQL.Statement).%New()
    s query = "select %ID,prop3 from mp.test where %ID in  (SELECT * FROM  (SELECT TOP ALL %ID FROM mp.test  WHERE prop1 = 2 ORDER BY prop3) WHERE %VID BETWEEN 3000000 AND 30000005)"
    w !,"Query Before Prepare:  ",$zh
    s sc=sql.%Prepare(query)
    w !,"Query After Prepare:  ",$zh
    i $$$ISOK(sc) {
        s rset=sql.%Execute()
        w !,"Query After Execute:  ",$zh
        i 'rset.%SQLCODE {
            s t1=$zh
            d rset.%Next()
            w $zh-t1,!
            d rset.%Display()
        }
        w !,"Query All Processed:  ",$zh
    } else {
        w $System.Status.GetErrorText(sc)
    }
}

/// d ##class(mp.test).Test()
ClassMethod Test()
{
    w !,"Before fill: ",$zh
    d ..Fill()
    w !,"After fill: ",$zh
    do ..Query()
}

}

Terminal Output:

DEV>d ##class(mp.test).Test()
 
Before fill: 84807.575139
After fill: 84807.575144
Query Before Prepare:  84807.575158
Query After Prepare:  84807.666853
Query After Execute:  84807.6669688.009005
ID      prop3
 
0 Rows(s) Affected
Query All Processed:  84815.676129

Have you tried that with an order by on one of the fields?

When doing the order by, you need to select a top all on the inner query so that it can order by. 

The sorting needs to happen before the %VID filters areapplied.
Example: Filter on a property that has a bitmap index for many records.
order by another property wich is an alphanumeric value, which is not unique.

Yes. The top all kills the performance.

59.516 seconds from 7.8 seconds without the order by and top all.

I am having similar issues.
The speed is faster, but the order by is necessary.

Our table holds around 5M entries, with the select done as per above, it still takes 7 to 8 seconds to load each page, which is unacceptable for my client.

I have not looked at RESTForms, so I can only provide a biased opinion on the DynamicObject Adapter.

We have used this for REST CRUD interfaces. This enabled us to use the same message structure classes for SOAP, REST XML and REST JSON interfaces. On the REST interfaces we use the ContentType to determine whether we should use the XML Reader to parse or the DynamicObject adapter. After the parsing, we encapsulate the message instance in an Ensemble message to invoke a business service in the cases where it is not just CRUD.

Thanks Dmitry.

Great stuff. Thanks. Where can I get the sample files and/or some instructions on the use of Kubernetes as demonstrated?

Thanks. I think that is one of the sessions I wanted to attend, but never got to it. I still need to go watch all the ones I wanted to attend, but had to choose between sessions or got pulled into meetings.

Missed that bit. I was only looking at the part I wanted. Such a typical developer thing to do 

Thanks. Appreciate it. If  I'm writing a method that uses this class in another namespace, I should be able to just zn to %SYS in the code in order to use the class.

Thanks. I will try from the %SYS namespace. I was trying to access it in another namespace. It also does not show in the class explorer. One of those "hidden" features.

To implement a pause prior to continuing the loop, use the hang statement.

The code provided above is perfect for all the other requirement. After the closing bracket of the "catch", add "hang 10" for a ten second "sleep".

You should also add a mechanism to stop this iteration somehow. It will be good practice.

ClassMethod Start()
{

  
    While (^RunMyApp = 1) {
        try {
            do ..YourMainMethod()
        } catch err {
            //log error here
        }
        hang 10
    }

If you then want to stop your code from running, open another terminal or use the Management Portal and set the global value:
set ^RunMyApp = 0