GetSwizzled error in cache

 I  keep seeing  <INVALID OREF>zMypropertyGetSwizzled+3^myClass.2  in the error log.  In my case,  Myproperty   is a property of  myClass. And Myproperty points to the the object of other class in the system. This error happens to 2 properties in the same class, and they are both object properties. This error pops up occasionally, and make the debugging harder.

Anyone knows what the issues are?


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the code causing the problem in 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

Those codes are not real codes, just give an idea what is happening ( I can't post real codes). The real codes works fine until couple days ago I start seeing those errors.

the $zv returns:

Cache for UNIX (IBM AIX for System P5-64) 2010.2.4 (Build 802_1_17238) Tue Apr 4 2017 19:48:24 EDT

ClassMethod myfuct( id) As %String
  set ref=##class(myClass).%OpenId(id)
  If '$isobject(ref) quit "no object 1, no return"
  if '$isrobject(ref.
Myproperty1) quit "no object 2, no return"
  set str="my return: "_ref.Myproperty1.OtherClass1Property
  quit str


Please post this line of code (Open myClass -> See other code -> zMypropertyGetSwizzled routine, third line) :


class myClass extends (%persisten)


Property Someproperty As %String;


Property Myproperty1 As   OtherClass1;

Property Myproperty2 As  OtherClass2;

... some more other property total 215 properties in this class


class OtherClass1 extends (%persisten)


Property OtherClass1Property As %String;


ClassMethod myfuct( id) As %String


set ref=##class(myClass).%OpenId(id)

set str="my return: "_ref.Myproperty1.OtherClass1Property

quit str


Above is a  similar situation and codes. When myfuct is called, sometimes it throws a  <INVALID OREF> zMypropertyGetSwizzled+3^myClass.2

myClass is  a very busy table.

You need to press "View other code" button (or Ctrl+Shift+V) and post zMypropertyGetSwizzled routine.

zMypropertyGetSwizzled(%this) public {
If $zobjval(,/*i% Myproperty */163,0,3,163)="" Quit ""
Set oref=##class( OtherClass ).%Open($select($zobjval(,/*i%Myproperty*/163,0,3,163)="":"",1:$listbuild($zobjval(,/*i% Myproperty */163,0,3,163)_""))) If oref="" Quit ""
Set modstate=$zobjval(,0) Set $zobjval(,/*r%Myproperty*/164,0,3,164)=oref Set $zobjval(,0)=$e(modstate,1,$l(modstate)\2)_$e($zobjval(,0),$l(modstate)\2+1,*)
Quit oref }

In the above sample, Myproperty can be Myproperty1 or Myproperty2. Any thoughts?

you do 

set ref=##class(myClass).%OpenId(id)

but you don't check if you really got an object.  the id might be invalid
continue with 

if '$isobject(ref) quit ""

It is valid in the db, just not getting it.  Don't know why. I am new to this.

you need an oref in ref 
and also in Myproperty1, ... 
So you have to check both . see answer

Thanks! very Interesting find. I will try that tomorrow. GetSwizzled  means getting object from memory or what? I don't quite understand this.