If my Remote Desktop Connection Broker server goes down, can users still access my two Terminal Servers?

Question

I am using XMLElement and XMLAgg functions in Oracle 11g to generate an XML String. This XML String this then sent to another system for parsing. I want to append the following text to the result of my XML.

The problem is, if I append the text as is, the SQL Statement returns the following -

    <ZAVACOR_RESULTS>
      <TEST>
        <BATCH>
          &lt;BATCH_OBJECTS&gt;&lt;ORDER_NUM&gt; 0     &lt;/ORDER_NUM&gt;&lt;/BATCH_OBJECTS&gt;
        </BATCH>
      </TEST>
    </ZAVACOR_RESULTS> 

I want the result to look like this -

    <ZAVACOR_RESULTS>
      <TEST>
        <BATCH>
          <BATCH_OBJECTS><ORDER_NUM>0</ORDER_NUM></BATCH_OBJECTS>
        </BATCH>
      </TEST>
    </ZAVACOR_RESULTS> 

This is my query. Any help would be much appreciated:

    SELECT
    XMLElement("ZAVACOR_RESULTS",
    XMLAgg( 
        XMLElement("TEST",
            XMLElement("BATCH", (case when t.batch is NULL then '<BATCH_OBJECTS>            <ORDER_NUM> 0 </ORDER_NUM></BATCH_OBJECTS>' else t.batch end)),    
            (SELECT 
                XMLAgg( 
                    XMLElement("BATCH_OBJECTS",
                        XMLElement("ORDER_NUMBER", (case when bo.ORDER_NUMBER is NULL     then 0 else bo.ORDER_NUMBER end))  
                                )
                       )
             FROM BATCH_OBJECTS bo WHERE t.SAMPLE_NUMBER = bo.OBJECT_ID and                                     
             t.SAMPLE_NUMBER = 705000088556  and t.TEST_NUMBER = 4537048 
                          )
                         )
                    )
        ).getClobVal() as XML 
    FROM TEST T WHERE t.SAMPLE_NUMBER = 705000088556 and t.test_number = 4537048;

---

Data Relationships:

TEST.TEST_NUMBER ---Number, Primary Key
TEST.BATCH --- Varchar2, Can be NULL
TEST.SAMPLE_NUMBER --- Number

BATCH_OBJECTS.BATCH --- Varchar2, Part of Composite Key
BATCH_OBJECTS.ORDER_NUMBER --- Number, Part of Composite Key

Solution

How are you doing load balancing between the two? If you are using a simple round-robin DNS distribution then if the connection broker goes down (provided that it is only providing that single role), then the terminal servers should continue to operate. People will still be able to connect to the servers, and load will continue to be split between the servers.

The load between the servers can and will become somewhat unbalanced. But If you leave enough head-room on your servers, this probably won't be that big of an issue.

If a person loses their connection, gets disconnected, and attempts to reconnect, they may be connected to a different server. In that case, they would have two open sessions. They would possibly lose some data, particularly if they tried to work on a file that was already open in the other session.

Comments

[Admin]

The title of this question does not sound right when read out loud. You may want to edit it using the edit link.

[Admin]

Thanks, I don't know what I was thinking when I posted it. Title edited.

[ERS]

Sorry, I am having trouble with formatting the question. I want my result to look like this - <ZAVACOR_RESULTS> <TEST> <BATCH> <BATCH_OBJECTS><ORDER_NUM> 0 <ORDER_NUM><BATCH_OBJECTS> </BATCH> </TEST> </ZAVACOR_RESULTS>

[Zoredache]

Connections are not made through the session broker, unless you also have NLB or something else running on the same system as the session broker. The session broker is only consulted when a RDP connection is being established.

[Frank Owen]

We will be using round robin to split the load between the two servers. This is exactly the information I needed. Thank you for your help!

[Alex Poole]

I suspect you've made this more complicated than it needs to be, but without more sample input and output I'm not sure. The subquery in the middle looks odd, and the nesting of the elements looks strange too, if there is real data. I'd also probably use nvl instead of case here, just because it's shorter.

[ERS]

Thank you Alex for your reply. TEST.BATCH is a varchar2. If I use the XMLType function, I get the desired output when TEST.BATCH Is null. However, I get oracle parsing errors (ORA-31011, ORA-19202, ORA-06512) if TEST.BATCH returns a value. Can I work around this?

[Alex Poole]

Again, you haven't shown any sample data. That error suggests your batch column does not contain an XML-style snippet. So what are you really trying to do here? If batch is null - does that imply there are no batch_object records? The relationships aren't clear.

[ERS]

The real problem I am trying to solve is that if TEST.BATCH is NULL, the entire block following that (Select order_number from BATCH_OBJECTS) is also Empty since TEST.BATCH = BATCH_OBJECTS.BATCH. This is the reason I am trying to append the XML String <BATCH_OBJECTS><ORDER_NUM>0</ORDER_NUM></BATCH_OBJECTS>.