Maybe someone is looking for job security.  

Regarding 

You will miss out on DTL specific functions (example lookups), albeit you could call the look up code in COS

some might think that using classes with COS code is better as it allows you to call any funtion you like. I think that's demonstrating a lack of knowledge.  If you created a class that extends Ens.Rule.FunctionSet , the functions then become available to anyone using the DTL or Rule Editor.

Additionally the new Rule Editor allows for ForEach whch otherwise might have been difficult to implement in the past.

I'd much rather be spending my time working on more advanced parts of an implementation instead of DTLs and Rules.

The only odd thing about DTLs and Rules is when you ask a business analyst to be involved they might not feel as strongly about following a rigorous CI/CD process. In my experience, some folks like to make changes to the DTLs and Rule and not commit to a feature branch and promote up thru the different environment(TEST,STAGE,PROD) as would normally be done if one was striclty in a class, even thought DTLs and Rules are in fact classes.

will this implementation be employed for the HealthShare ATNA tables as these have billions of rows at customer sites

Isnt this the data from the class/table %SYS.Task and why not just use SQL or Objects?

In the past what I have done is define a Web Application with a REST Dispatch class and in that class serialize the data from the JSON payload into a real message class with properties.  In this way the Business Service receives a request object with the properties defined and now the Message Viewer has the expected functionality.  This also means that the business service is not purlely a tied to REST.  Anyone that sends a proper pRequest object can use the business service.

The documentation link reports

https://docs.intersystems.com/hs20241/csp/docbook/DocBook.UI.Page.cls?KE...

When version checking is implemented, the property specified by VERSIONPROPERTY is automatically incremented each time an instance of the class is updated (either by objects or SQL). Prior to incrementing the property, InterSystems IRIS compares its in-memory value to its stored value. If they are different, then a concurrency conflict is indicated and an error is returned; if they are the same, then the property is incremented and saved.

I've used the VERSIONPROPERTY  parameter before and have observed that it is updated each time the object is saved.

You might also look at https://docs.intersystems.com/hs20241/csp/docbook/DocBook.UI.Page.cls?KE...

Have you looked at utilizing

https://docs.intersystems.com/iris20243/csp/docbook/Doc.View.cls?KEY=GSQ...

@Jennifer Dennis  I didnt see an official announcement of ZEN being discountinued in 2025. 

What specifically does "discountinued" mean? 

Does this mean all of our ZEN application pages will no longer work with a 2025 kit?

The video talks about using the published APIs.  I assume this specifically referes to the APIs in the Security package.  My specific question is will we still be able to write SELECT statements against %SYS.Audit and will anything special need to be done to be able to do so.  Will we have to update users to add resources or grant permissions?

which is responsible for some batch operations with an SQL table

Is this a native IRIS SQL Table and have you examined the Query plan for the SQL Table?

If you run the report via the browser 

MSDS.Maintenance.Report.CBMReport.cls?LocID=loc&WOID=wo&LineID=lineId&$MODE=PDF&$LOG=1

where the values of loc,wo, and lineId

is there anything helpful reporting in the log.

Might you be able to share the 2 sql statements and the query plans?

If you are running the queries in the System Management Portal there is a limit that you could set 

but I dont imagine that is the issue.

Where possible a COUNT(*) query could chose to use your indices and in theory your indices might be different from your table data but that would be highly suspicios under normal circumstances as the writing to the table and the indices are in a database transaction so it should have all been written or not.  

To your specific question

Is there something inherent with the queries that limits the result set size, or anything I can do to make sure I'm getting back all the results? Rather, than trying to run it about 100 times limiting all previously gotten accounts.

Again if you are running via the System Management Portal there are times I run the query with a limit of 100 for example and once the results are presented I select the Print hyperlink to run the entire query results to a file

I believe we can determine this by using

SELECT distinct SystemVersionNumber
FROM ZPM_Analytics.Event
where Action='install'
order by SystemVersionNumber

On our private registry we see the following

SystemVersionNumber
2020.1
2021.1
2021.1.2
2021.1.3
2022.1
2022.1.2
2022.1.4
2022.2
2022.3
2023.1.1
2023.1.2
2023.3
2024.1
2024.1.1

This is why we have been adovocating to have Username in the table ZPM_Analytics.Event as we create a Username for each one of our "clients" and can trace back who these install records are specifically for,

when you say using IPM do you mean perfoming "install -v moduleName" on IRIS or do you mean creating a registry on IRIS earlier than 2022.1

Using the message viewer you can add criteria and search by 

I'm assuming folks from InterSystems have a more formal way of saying "you have a partner with InterSystems".  When the occasional crisis occurs, the support of many folks from WRC rally around your issue and see it to the end.  Having the ability to contact someone on the other end and resolve crisis issues is not something you are likely to get from other vendors.

Looking at your example class, and maybe its not practical as we aren't seeing the entire context of your real world usage but might you see better resuilts if you were using instead of a composite index on prop1, prop2, prop3 but rahter bitmap indices on prop1 as it seems like it is the field name and would have a suffeceintly small number of values, a bitmap index on prop2, and a traditional index on prop3.  

If you were to show the query plan that would also provide some insight.

I would imagine if you have a license from Intersystems you could install Cache, mount the DB, and then the next question is "Was the application developed back in 2017" with an SQL interface, ie are there SQL tables that exist for the database that you have?"  If so you could connect to the db via ODBC and extract the data.

If not then that's a much large endeavor as you would need to have the tables defined and depending on how much meta-data/documentation you have for the data that could be quite involved.