is just a Global variable to maintain the actual state of the display structured by Worlds and Display lines.
And it rebuilds the image in cyles.

It has nothing to do with the class definition but is an independent structure.
So you just see it in various methods.

Honestly, I never saw an <INVALID OERF> related to a lack of memory.

It typically happens if you do set obj=##class(MyClass).%OpenId(id,,.status)  and do not check for success.

https://cedocs.intersystems.com/latest/csp/documatic/%25CSP.Documatic.cls?PAGE=CLASS&LIBRARY=%25SYS&CLASSNAME=%25Library.Persistent#METHOD_%OpenId

so if you miss if '$isobject(obj)  {  .... error processing  using status....} or similar

then the next access to obj.MyProperty will throw  <INVALID OERF>

Only checking the status will tell you if  you really ran out of memory

keyword RENAME TO is not supported by ALTER TABLE see docs.

https://cedocs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=RSQL_altertable

The management portal has various screens with update features. (e.g Job status)

Íf IRIS service stops the update fails with a timeout.  This is your alert.

with

&SQL(SELECT MAX(ID) FROM Cinema.Film)

you eliminate the need of ORDER BY ... and save time

ERROR <Ens>ErrException: <METHOD DOES NOT EXIST>zCopyFrom+28^%Stream.TmpCharacter.1 *Rewind

Pls. add Version. (I couldn't identify any REWIND in CopyFrom)

If you don't have a similar drive you may need to update %installdir%\cache.cpf

if this isn't enough 

startup Caché in emergency mode as described : 
 https://cedocs.intersystems.com/latest/csp/docbook/DocBook.UI.Page.cls?KEY=GCAS_secmgmt#GCAS_secmgmt_emerg

and run  DO ^STURECOV from namespace %SYS

it allows you to disable Journal Checking for the next startup.
then restart Caché

I fear there is no such utility by default. 
You may need to do it manually to see if it is a real problem or a side effect from parallel compiling.

I just verify it by multiple runs on CompileAll to be sure.

 [ I'm  just  facing a list of ~100 including deployed classes     ] 

If you have private %classes mapped ito %SYS then you have to compile them manually.

compileAll doesn't include %SYS for good reasons. 

use instead.

set ID=##Class(User.School).%OpenId(RollNo_"||"_Marks,,.sc)

do $system.OBJ.DisplayError(sc)

now you should see the reason why  ID=""

docs: https://cedocs.intersystems.com/latest/csp/documatic/%25CSP.Documatic.cls?PAGE=CLASS&LIBRARY=SAMPLES&CLASSNAME=%25Library.Persistent#%OpenId