A Compile has also an errlog parameter ist is clear that it does an inner error trapping.

.
 therfore at termination it doesn't end in your catch{ }
 I think it may even react specially on RESJOB by just doing a HALT.

in a development environment, you may try to investigate this using a %ZSTOP routine

I found this much more interesting! 
Stable with growth and double score from the follower.

I remember a similar situation some years back with a rather sophisticated multilevel directory structure on UNIX.

The final solution, especially for al kind of searching in unique file names, was a class
with the filename as ID and directory, summary, creation date, last modification as properties.
The search (in SQL) out performed anything used before.

The only extra work was kind of a register at file creation/modification which happened at a moderate rate.  
+ a nightly batch job to verify and do the reality check. 

no details. what OS pls.?

use Do $System.OBJ.ShowObjects() to list your refernced objects.

The output goes to $IO or eventually a TmpCharStream.
The start of the last line is your count of orefs .

It starts with the basic definition:
What is LEGACY for you?  any MUMPS dialect  (DTM. DSM, ISM, ...) ?

From the language elements, there is all included and possible. what was available in MUMPS.
Except that System variables may have some differences that need to be checked.
In general, you have enhancements at all levels: Commands, Functions, Variables

One of the significant differences is variable scoping.
In legacy MUMPS you had your partition and all variables were visible everywhere.
In COS this visibility is managed at various levels and you have to take control over the variable scope.

see this articles:
Variable scope in .mac routine?
Summary on Local Variable Scoping

Of course, interaction with external devices and peripheral is different.
But this doesn't affect programming style.

I assume you have some special techniques in mind.
For questionable cases, this forum is the place to get help at almost any level.
And often it's more than a single unique solution but a choice of variants the members offer.

 I  personally have seen code written on DSM-11 in 1978, copied to Caché and running without change.
This was core logic. Communication with peripherals needed adaption. No surprise.

but I doubt that XML Schema Wizard will do anything useful with a .dtd definition.

To use httpS://  in xml schema wizard you need to definde an  SSL configuration in  SMP  System > Security Management > SSL/TLS Configuration.

1) install gbk character set table to your instance (if available)

??? ....\InterSystems\Cache\mgr\Locale\allmessages_zh-cn.xml ???

2) use  $zconvert()  to translate it.

if 1) fails you may trigger an external converter using $ZF(-2 ,....)

or use command pipe to run an external conversion. 

What error is "some" ?

Detailed description on ADD FOREIGN KEY

Look especially on

Go to the Management Portal, select [Home] > [Configuration] > [General SQL Settings]. View the current setting of
Allow DDL ADD Foreign Key Constraint When Foreign Key Exists.