AllAccepted answers
Robert Cemper · Aug 1, 2020

  @Evgeny Shvarov 
     Are you looking for something like this ?

this is the related query:

select %vid AbsRef
    , TO_CHAR(Day,'YYYY-MM-DD')  Day
    , Seq 
    , $PIECE($PIECE(p,'$ZE=',2),'>',1)||'>' Type
    , $PIECE($PIECE(p,'>',2),',$ZV',1)||'>' Line
    , $PIECE(p,'$ZV=',2)||'>' Version
 from (
    SELECT TOP ALL
       day, seq, LIST(item||'='||value) p
       FROM zrcc.ERRORStack 
       WHERE Stacklevel=0
       AND item IN ('$ZE','$ZV')
       GROUP BY day,seq
)
Robert Cemper · Aug 1, 2020

out of the experience: every project in ZPM needs its personal package.

otherwise, you may see this:

ERROR #5001: Resource 'rcc.PKG' is already defined as part of module 'echoserver-wsock-iris'; cannot also be listed in module 'iris-internal-websocket-client'
ERROR #6315: FErrors reporting importing XML subelement in file  'C:\InterSystems\IRIS\mgr\.modules\USER\iris-internal-websocket-client\1.0.0\module.xml', at line'3', offset '55'. skipping this item.

Robert Cemper · Jul 30, 2020

Thanks for the hint. 
I was pretty sure there should be something similar to serve SysMgmtPortal. I just didn't know.
Obviously the authors had the same problems as me with the old structure and applied a bunch of custom queries.
I don't think I missed something:
- the class is deployed so you have to accept what it does.
differently  %ERN.int doesn't hide anything and speaks full truth. 
- next to use it you require full access rights to %SYS and a namespace change %SYS to run it.
- and finally the topmost requirement: The queries are invisible to SQL! 
Just because not being exposed as SqlProcedure.

My solution runs in any namespace on Caché / Ensemble / iris .
Without any privileges and doesn't touch any ISC copyrights!

Robert Cemper · Jul 29, 2020

Just to outline my understanding:
my package will be rcc.subject.classname   
rarely eventually zrcc.subject.classname  if it should go to %SYS .

And I will not touch/ rename existing projects as this means changing not just the code
but also README.md , Descriptions in OEX and Articles in DC, Screenshots, Dependencies (not just my own), ...
Over all a good source for mistakes, typos, errrors, confusion, 

Robert Cemper · Jul 28, 2020

The so-called SQLformat doesn't exist in Caché (at least not in the last 20 years)
But over the gateway, you can move data from Caché to PostgeSQL.  "from a table on CACHE  to a POSTGRESQL table"

So you need a trigger to do it:
- Caché has to be the active part here
you can start the upload over a webservice, an REST call, even as an SQLprocedure, or automatically by the scheduler
And if you don't want to touch your target table directly you may have a shadow-copy in PostgreSQL that
then serves as a source for your final updates.  ( some INSERT...SELECT....)

So instead of import from CSV, you do an import from a local table in PostgreSQL
Anything is better than CSV.
This would even allow filling your shadow over the day in small steps instead of a big bang (if needed)