the code causing the problem in MyClass.2.int looks most likely like this:

Set oid=$select(i%Myproperty="":"",1:$listbuild(i%Myproperty_""))

you are inside an ObjectMethod   and miss the actual Object  reference.
This happens when you try to access a property inside a Classmethod.
 classic mistake:

ClassMethod MyMethod(1,2,3) as %Status {
 set x=..Myproperty
}

correct use: 

ClassMethod MyMethod(oref,1,2,3) as %Status {
 set x=oref.Myproperty
}

Whether external backup or backup from a mirror (also asynchronous) or Caché backup you always have to identify
the point in time when your DB is logically consistent. What I think of is no open transactions, no open dependencies.

If you know that point in time you could separate your async mirror or shadow and run any backup from there.
Or just shut down your async server instance and run snapshots.
But there might also be a time gap between master and async server.
Once completed your async server can join again and catch up whatever time that may take.   
The critical point is to know when the async server has reached consistency.
But that depends on the application.
 

for a file stream it's a physical file, for a global stream it's a global or part of it.
if you clear it you either delete the file or the global (or its part )that holds the stream.
stream in Caché describes a sequence of persistent bytes on disk that you work on with dedicated common methods.

this must not be mixed up with a stream of characters on a network connection. if you miss a character there it's gone. 

Hi Alexey,
You hit the point: "lightweight"  just documents the relation.  Full stop. No further service.
You have to service (ie. Delete) it at both ends.
If you use a serial object with OREF + Status)  you still have to service both ends.

The "heavy" variant does it centralized at one place.
Though from storage point of view you move out the additional subscript level from array.

Hi, Evegeny!
for both variants you work along the array by GetNext() method
for each employee you have an array with the OREFs of the company. So you have the full object at hands.
similar the opposite direction from company to employee and employee->nae in SQL or employee.name

And as we always have a Collection type Array indexing is simple either by (KEY) or (ELEMENT). whether you  need the ID or the OREF
http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=GSQLOPT_indices#GSQLOPT_indices_collections

The only tricky action is DELETE: there you have to have a method to "DisRelate" before delete.
But real commercial systems never delete anything. Just set a flag "isDeleted". Which is much easier for any "undo" action. 

You look for INSERT from Query
doc is here http://docs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_insert#RSQL_insertselect

As far as I see it should work the way you have written
(assuming data types between target and source match) 

To estimate runtime you may try the select count(*) from  VwSrcTable  first to get a feeling
how many records that will be. 

Then during load running Select count(*) from DestTable from a 2nd session may let you see your progress.
 

SQLCODE -99 Privilege violation

You have 3 different sets of access rights in this scenario

  • your  development user    
  • the application user
  • the user your Caché / ENS server installation is running on

Check if also  your server has the required access rights at OS level.
under *IX it's quite likely that you don't run as root.
(though this happens also on other OS)
 

It was first documented in 2015.2
chapter 12.1.1 p.108
http://docs.intersystems.com/documentation/cache/20152/pdfs/GSQL.pdf

• Dynamic SQL can accept a literal value input to a query in two ways: input parameters specified at execution time
using the “?” character, and input host variables (for example, :var) specified at prepare time. Embedded SQL uses
input and output host variables (for example, :var).

An interesting observation!
IT WORKS !

I just retyped it a little bit extended for fast retry:

set minage = 80
set myquery = 3
set tStatement = ##class(%SQL.Statement).%New()
set myquery(1) = "SELECT top 10 %ID AS id, Age , Name, %ODBCOUT(DOB) DOB, Home_State"
set myquery(2) = "FROM Sample.Person WHERE Age > :minage"
set myquery(3) = "ORDER BY 2"
set qStatus = tStatement.%Prepare(.myquery)
set tResult = tStatement.%Execute()
do tResult.%Display()
in SAMPLES:
id      Age     Name                    DOB     Home_State
16      82      Schaefer,Alvin S.       1935-05-05      HI
108     82      Adams,Brian Q.  1936-02-21      IL
199     82      Yeats,Ashley K. 1935-10-28      NC
74      83      Ravazzolo,Molly I.      1934-12-31      WV
63      84      Cheng,Filomena J.       1933-12-27      NM
69      84      Yeats,Patrick U.        1933-04-19      KY
92      85      Lepon,Liza M.   1932-06-03      MN
94      87      Browne,Patricia I.      1930-04-05      AL
111     87      Orlin,Edward J. 1930-04-10      OR
197     87      Rogers,Barbara M.       1930-12-06      WI

It also works using traditional %ResultSet

Though I didn't interpret nor use it that way it is documented here:

Dynamic SQL versus Embedded SQL    (4th point)

Dynamic SQL can accept a literal value input to a query in two ways:
input parameters specified using the 
“?” character,
and input host variables (for example, :var).
Embedded SQL uses input and output host variables (for example, :var).