Class User.Utility.Tasks.PurgeCustomMessages Extends %SYS.Task.Definition
{

Parameter TaskName = "PurgeCustomMessages";

Property MaxDelete As %String [ InitialExpression = 1 ];

Property MinBodyID As %String [ InitialExpression = 1 ];

Method OnTask() As %Status
{
    //Get The Types of message classes
    Set sc = $$$OK
    s tMessagesToOrpahan=0
    //open up table of messages types to purge 
    try{
        Set rs = ##class(%SQL.Statement).%ExecDirect(,"select Keyname as MessageBodyClassName,Datavalue as ObjectSQLQryName from Ens_Util.LookupTable where tablename='OrpahnedMessagePurging'")
    }
    catch err {
       Set sc = err.AsStatus() 
       //quit st
    }
    
    While rs.%Next() 
    {
        set msgBodyName=rs.ObjectSQLQryName
        set className=rs.MessageBodyClassName
        if msgBodyName="Ens.MessageBody"{
            set tMinMsgId=..MinBodyID

        }else{
        set tMinMsgId=..GetMinimumIDForMessage(rs.MessageBodyClassName)
        }
        Set tSuccess=0
        Set tFailed=0  
        set dt=$translate($zdatetime($horolog,8,1), " :", "")
        if tMinMsgId '=-1
        {
            set msgQuery="SELECT top ? ID from "_msgBodyName_" where id <?"
            set tStatement = ##class(%SQL.Statement).%New()
            set qStatus = tStatement.%Prepare(.msgQuery)
            if qStatus '= 1 {
                s ^OrphanedMsgTask(dt,msgBodyName,"Error") ="Prepare Failed"
                s sc= $System.Status.DisplayError(qStatus) quit}
            
            set tResult = tStatement.%Execute(..MaxDelete,tMinMsgId)
           
           While tResult.%Next() 
           {
                s tMessagesToOrpahan=1

                            try{
                                SET tSC1=$CLASSMETHOD(className,"%DeleteId",tResult.ID)
                            
                            if tSC1=$$$OK{
                                set tSuccess=tSuccess+1

                            }
                            else{
                                set tFailed=tFailed+1
                                s ^OrphanedMsgTaskFailed(className,tResult.ID)=tSC1
                            }
                            }
                            catch 
                            {
                                set tFailed=tFailed+1
                                set sc = $$$ERROR($$$GeneralError,"DeleteID Failure"_tResult.ID)
                                s ^OrphanedMsgTask(dt,msgBodyName,"Error") ="DeleteID Failure"
                            }
           }
        }
        else
        {
            s ^OrphanedMsgTask(dt,msgBodyName,"Status")="No messages in header table for "_msgBodyName
        }
        
      s ^OrphanedMsgTask(dt,msgBodyName,"Status")="Purged for "_msgBodyName  _" "_tSuccess_" messages and failed to purge " _tFailed _ " messages"   
    }
   
    quit sc
}

/// Method to return the minimum ID for the message type you are purging 
ClassMethod GetMinimumIDForMessage(pMessageType As %String) As %String
{
    set MessageID=-1
    set minIDQuery="SELECT  TOP(1) MessageBodyID  FROM Ens.MessageHeader where MessageBodyClassName=?"
    set tStatement = ##class(%SQL.Statement).%New()
    set qStatus = tStatement.%Prepare(.minIDQuery)
    if qStatus '= 1 {write "%Prepare failed:" do $System.Status.DisplayError(qStatus) quit}
    set tResult = tStatement.%Execute(pMessageType)
    While tResult.%Next() 
    {
    set MessageID=tResult.MessageBodyID
    Write tResult.MessageBodyID, !
    }
    w MessageID
    return MessageID
}

ClassMethod StreamPurge() As %Status
{
    set i=1
    while (i<200000){
        k ^CacheStream(i)
        s i=i+1
    }
    q $$$OK
}

ClassMethod Test() As %String
{

    set msgQuery="SELECT top ? ID from EnsLib_HL7.Message where id <?"
            set tStatement = ##class(%SQL.Statement).%New()
            set qStatus = tStatement.%Prepare(.msgQuery)
            s ^OrphanedMsgTask = qStatus
            if qStatus '= 1 {write "%Prepare failed:" do $System.Status.DisplayError(qStatus) quit}
            s ^OrphanedMsgTask =tStatement
            set tResult = tStatement.%Execute(1,..GetMinimumIDForMessage("EnsLib.HL7.Message"))
            While tResult.%Next() 
            {
                w tResult.ID
            }
            quit qStatus
}

/// Classmethod to create a list of the message types 
ClassMethod MessageTypes() As %ListOfDataTypes
{
    Set sc = $$$OK
    Set rs = ##class(%SQL.Statement).%ExecDirect(,"SELECT DISTINCT (MessageBodyClassName) AS messageType FROM Ens.MessageHeader where MessageBodyClassName Like 'messages%'")
    set messageTypeList=##class(%ListOfDataTypes).%New()
    While rs.%Next() {
        do messageTypeList.Insert(rs.messageType)
    }
    w messageTypeList.Count()
    for i = 1:1:messageTypeList.Count() {
        write !, messageTypeList.GetAt(i)}
}

No idea how to upload a file so here is the class 

Thank you, it is a 700gb database, good to know this is ok thought this would be the case so will go with this strategy of truncating

Thank you

How do you delete the task?

Thanks missed reading that

Thanks didn't see that 

have changed to the below which works from your answer

Set node = $Query(^FromExtraMed(""),1,nodevalue)

 while (node '="")
 {
 write nodevalue,!

 Set node = $Query(@node,1,nodevalue)

}

The example with the @ with this still brought back any other nodes of je1 not just that "not configured" node

found the following to do what required from Use a global stored in variable. | InterSystems Developer Community |

s global="^je1(""NotConfigured"")"
s sub=""
f  s sub=$o(@global@(sub)) q:sub=""  w !,sub 

Hi Still not working. Might be my misexplaining

Two values from the global veiw page

1:  ^je1("NotConfigured","CBB") = "" 2:  ^je1("NotConfigured","CH11") = "" Total: 2 [End of global]

All i'm getting is the first 

Set node = $Query(^je1("NotConfigured"))
   WRITE !,node
  FOR   {
    SET queryary=$QUERY(node)
        QUIT:queryary=""  
        WRITE !,queryary
        SET node=queryary
  }

In terminal we would have used ^%G then je1("NotConfigured", looking the exact same but in code in objectscript

queryary is blank after the first query so node is blank

Thanks Oliver this has been great. I have created a fork of this original code for our own use- i don't use github too much so hope this is an ideal way to keep the information sharing from your initial work done that was great. I have not included on an error section due to trying to keep things simple on a monitor screen but it could be added if others wish. If there are further updates will try keep my code on github for this up to date if possible and still quite non bespoke as seems fair for anyone who wants a better solution. 

I plan to be accessing it via a website saved in intersystems server to be accessed on the server. I have some ideas how it will look/work. Is mainly the finding the current errored services as one of the things I just can't seem to find in existing code how to get the status. I plan to have any suspended and queues or where intersystems has stopped a operation because of E=D  but think I know ways to get the rest of this to make a really nice clean clear monitor page