How do you launch the code?

Comment out  OnGetConnections method and restart the service.

Do you still get errors?

I would like to advise against this course of action, there are several reasons:

1. Ensemble messages should be as small as possible. If you can pass id only, pass id only, etc. Minimizing message size keeps production efficient.
2. ResultSet does not contain the data itself, it's more like a compiled instructions on how to get the data. Only when you're calling Next method the data is actually loaded into memory
3. Results of SQL query should be immediately acted upon, because the older the SQL results, the more they differ with reality. it is best to pass parameters and execute query in-place.

If you want it for debugging purposes you can add a trace event which would store ids only for example, but if you actually need to pass a set of results between different business hosts it may be beneficial to you to rethink the production architecture.

Here's some questions:

1. What business hosts do you have?
2. What data do you pass between different hosts?
3. Can you pass parameters between hosts and execute a query on a target host?
4. Can you pass not a set between hosts, but rather elements individually?

Better unhighlighted code than a picture.

Mint LaTex package uses Pygments as an actual colorizer.

It's actually a wrapper for the same idea - if HeadOfQueue is checked, the resend message is inserted with a higher priority than the highest priority existing queue message. It can be seen in EnQueue method of Ens.Queue class.

Bitmap indices maintain one node per each chunk of 64 000 id's, if at least one id from that range exists. So random integer ids can slow bitmaps down. On the other hand if there are two consecutive but spread (i.e 1..1000 and 100000...110000) id sequences it would generate just 2 global nodes so everything should be ok in that scenario.

Check index global in various scenarios:

Class Example.Bitmap Extends %Persistent
{

Property ID As %Integer(MINVAL = 1);

Property Value As %Integer(MAXVAL = 9, MINVAL = 0);

Index IDKEY On ID [ IdKey, Unique ];

Index ValueIndex On Value [ Type = bitmap ];

ClassMethod Populate(startid, endid, step = 1) As %Integer
{
    set count = 0
    do ..%KillExtent()
    for i = startid:step:endid {
        set count = count + 1
        set ^Example.BitmapD(i) = $lb("", $random(10))
    }
    
    do ..%BuildIndices()
    
    quit count
}

Query Select(value) As %SQLQuery
{
SELECT ID
FROM Example.Bitmap
WHERE Value = :value
}

/// do ##class(Example.Bitmap).Test()
ClassMethod Test()
{
    do ..TestOne(1, 1000000)
    do ..TestOne(100000000, 101000000)
    do ..TestOne(1, 1000000000, 1000)
}

ClassMethod TestOne(startid, endid, step = 1)
{
    set startTS = $zh
    set count = ..Populate(startid, endid, step)
    set endTS = $zh
    
    set populateTime = endTS - startTS
    
    set startTS = $zh
    set rs = ..SelectFunc($random(10))
    
    set endTS = $zh
    
    set queryTime = endTS - startTS
    
    write $$$FormatText("Start: %1, End: %2, Step: %3, Count: %4, Populate Time: %5, Query Time: %6", startid, endid, step, count, populateTime, queryTime),!
}
}

Eduard, are you referring to the Priority property of the Ens.MessageHeader class?

Yes.

That seems to be used exclusively for marking the message for Async vs. Synchronous delivery.

These priorities are available:

#define eMessagePriorityHighSync 1
#define eMessagePrioritySync     2
#define eMessagePrioritySimSync  4
#define eMessagePriorityAsync    6

Sync by default is 2, so specifying priority 1 may indeed help. Cursory glance at Ens.Queue indicates that messages with priority 1 would be processed first.

Yes. To get a full list of reserved works execute:

zw ^%qCacheSQL("reservewords")

But this also means that you can't ship the whole vendor copy of the global as you will overwrite the onsite ID counter node.

You can! When you load globals specify /mergeglobal flag to merge the global with existing data instead of overwriting it:

set sc = $system.OBJ.Load("global.xml", "/mergeglobal=1")

seed the ID counter at the site to a really high number

Bitmap indices would really slow down from that.