Use args... to supply a variable number of parameters:

ClassMethod DoCleverStuf(args...) As %Status [ CodeMode = objectgenerator ]
{
    do %code.WriteLine("    For i=1:1:args {")
    do %code.WriteLine("        Write args(i)")
    do %code.WriteLine("    }")
    do %code.WriteLine("    Set tSC = $$$OK")
    ...
}

can I generate a whole method at compile time?

You can use projections to do that. Here's an example.

Assuming you have a sync mirror established, adding new db to mirror is as simple as:

1. Create DB on Primary.
2. Run SYS.Mirror:AddDatabase. It returns %Status, check that it's ok with $$$ISOK(sc). It should be equal to 1.
3. Dismount database on Primary (using SYS.Database:DismountDatabase) OR Freeze IRIS (Backup.General:ExternalFreeze).
4. Copy IRIS.DAT to Backup.
5. Mount database on Primary (using SYS.Database:MountDatabase) OR Thaw IRIS (Backup.General:ExternalThaw).
6. Mount database on Backup.
7. Activate database on Backup (SYS.Mirror:ActivateMirroredDatabase).
8. Catchup database on Backup (SYS.Mirror:CatchupDB).

Please note that some methods accept db name, most accept db directory, and others db sfn. Please keep that in mind.

Try: ##class(%Studio.Project).InstallFromFile( "/display=none /displaylog=0 /displayerror=0")

You can make IRISLIB DB RW, but you'll lose changes on update.

Database is a physical file containing globals.

Namespace is a logical combination of one or more databases.

By default Namespace has two databases:

• GLOBALS - default location for globals
• ROUTINES - default location for code (classes/routines/includes)

In addition to that, namespace can have any amount of mappings. Mappings map specified globals/code from a specified database.

When you try to access a global, first global mappings are searched for this global, if no mappings are found, the GLOBALS database is used.

When you try to access some code, first package/routine mappings are searched for this code, if no mappings are found, the ROUTINES database is used.

To split data innto a separate DB:

1. Create target DB.
2. Make source DB RO (by forcefully logging users out for example and/or marking it as RO).
3. Copy data/code from the source to target DB (for globals use ^GBLOCKCOPY).
4. Create mapping from the target DB to your namespace.
5. Confirm that data is present.
6. Delete data from a source DB.

scheduled task that run every 5 mins  

Assuming task is scheduled like this:

it would be scheduled to run again 5 minutes after the completion of a last task execution, so there's no issue with several copies of a task running in parallel.

I would not recommend regexp for that. If you have one place with such a date, you can use transient/calculated property pair:

Class User.JSON Extends (%RegisteredObject, %JSON.Adaptor)
{

Property tsjson As %String(%JSONFIELDNAME = "ts") [ Transient ];

Property ts As %TimeStamp(%JSONINCLUDE = "none") [ SqlComputeCode = {set {*}=$replace({tsjson}," ", "T")_"Z"}, SqlComputed ];

/// d ##class(User.JSON).Test()
ClassMethod Test()
{
	set json = {"ts":"2022-02-02 01:01:34"}
	set obj = ..%New()
	zw obj.%JSONImport(json)
	w "ts:" _ obj.ts
}

}

If you have a lot of json properties,  use a custom datatype to do automatic conversion:

Class User.JSONTS Extends %Library.TimeStamp
{

ClassMethod IsValidDT(%val As %RawString) As %Status
{
    /// replace it with a real check
    q $$$OK
}

/// Converts the Objectscript value to the JSON number value.
ClassMethod JSONToLogical(%val As %Decimal) As %String [ CodeMode = generator, ServerOnly = 1 ]
{
    /// $replace({tsjson}," ", "T")_"Z"
    If 1,($$$getClassType(%class)=$$$cCLASSCLASSTYPEDATATYPE) || $$$comMemberKeyGet(%class,$$$cCLASSparameter,"%JSONENABLED",$$$cPARAMdefault) {
        Set %codemode=$$$cMETHCODEMODEEXPRESSION
        Set %code="$replace(%val,"" "", ""T"")_""Z"""
    } Else {
        Set %code=0 
    }
    Quit $$$OK
}

}

And use it instead of the standard timestamp:

Class User.JSON Extends (%RegisteredObject, %JSON.Adaptor)
{

Property ts As User.JSONTS;

/// d ##class(User.JSON).Test()
ClassMethod Test()
{
	set json = {"ts":"2022-02-02 01:01:34"}
	set obj = ..%New()
	zw obj.%JSONImport(json)
	w "ts:" _ obj.ts
}

}