Load Balancing, Server and / or Client ?

Question

Hi
I am experiencing a problem with the connection pooling in odp.net. I have a simple test app that creates a connection, executes a query, populates an object then closes the connection. I have found that when I have client side load balancing on via the odp.net connection string property many connections are made unnecessary (sometime the actual number created reaches the max pool size but the numbers differ randomly). It appears that rather than a free connection in the pool being used more connections are being created which defeats the point of having a connection pool. I do have server side load balancing configured correctly also. Due to this finding can someone possibly answer the following questions.
a) Do I need both server side and client side load balancing set?
b) If I do why is the above behaviour being seen? If not could you give me a short explanation as to why not?
Current set up is 11g (patched to 6, awaiting 7 to be applied) RAC, 2 nodes.
Below is the C# code used while testing this. The table queried is a simple person table containing 16000 rows if data.
OcConnection = "User Id=XXX; Password=XXX; Connection Lifetime = 60; Data Source=(DESCRIPTION=(ADDRESS_LIST=(FAILOVER=on)(LOAD_BALANCE=off)(ADDRESS=(PROTOCOL=tcp)(HOST=XXX)(PORT=1521))(ADDRESS=(PROTOCOL=tcp)(HOST=XXX)(PORT=1521)))(CONNECT_DATA=(SERVICE_NAME=MyFirstTest))); Pooling=true; HA Events = true; Load Balancing = true";
Code:-
Oracle.DataAccess.Client.OracleConnection con;
con = new Oracle.DataAccess.Client.OracleConnection();
con.ConnectionString =OcConnection;
con.Open();
// the command object to use for this test
OracleCommand cmd = con.CreateCommand();
cmd.CommandText = "select * from PERSON";
OracleDataReader rdr = cmd.ExecuteReader();
List<test> listTest = new List<test>();
while (rdr.Read())
test dc = new test();
if (!rdr.IsDBNull(0))
dc.id = Convert.ToInt32(rdr.GetValue(0));
if (!rdr.IsDBNull(1))
dc.forename = rdr.GetString(1);
if (!rdr.IsDBNull(2))
dc.surname = rdr.GetString(2);
if (!rdr.IsDBNull(3))
dc.street = rdr.GetString(3);
if (!rdr.IsDBNull(4))
dc.city = rdr.GetString(4);
if (!rdr.IsDBNull(5))
dc.postcode = rdr.GetString(5);
if (!rdr.IsDBNull(6))
dc.country = rdr.GetString(6);
if (!rdr.IsDBNull(7))
dc.email = rdr.GetString(7);
if (!rdr.IsDBNull(8))
dc.dateadded = rdr.GetDateTime(8);
if (!rdr.IsDBNull(9))
dc.randWords = rdr.GetString(9);
if (!rdr.IsDBNull(10))
dc.uniqueNumber = Convert.ToInt32(rdr.GetValue(10));
listTest.Add(dc);
rdr.Close();
con.Close();
rdr.Dispose();
cmd.Dispose();
con.Dispose();
Thanks for your time
Victoria

Answer 1

Here are the HTTP Headers as monitored on the client side. Notice the good.txt file includes a GET as it's initial request. All works fine in this case. However, the initial request in the bad.txt is a POST. This is odd since the URL was opened using the same shortcut in both incidents and the browser was closed between each trace that was taken. I've also reviewed the shortcut with notepad to verify it does not include unwanted data such as the JSESSIONID info....etc.
Once you have reviewed the HTTP headers, I have these questions.
1. IIS is sending the 100 Continue messages as you mention, but why is the CSS injecting the cookie in a 100 response that is not typically processed by the client? The bad.txt file shows the client receiving two ARPT cookies because the first cookie in the 100 continue response was ignored.
2. I know Cisco is not really in the business of troubleshooting browser behaviour. But do you know why the browser would behave differently....GET in one request and a POST in the next? We do not wish to get into modifying the browser, so I'm hoping we can provide a solution on the server side that will allow the browser to function this way if it chooses to do so. Do you think it would make sence to push the state management up a level to the cookie handed out by JRUN? This way, the cookie would not be handed back in a 100 response from IIS, and we could tell the CSS to monitor the JRUN cookie. Of course this would require we determine how to manage this cookie either by modifying to cookie to have static data for each server, or by using the right method of hashing...etc.
Chris