OCI sends duplicate TNS packet to Oracle server ?

Hi,

I am working with ODBC driver which uses OCI calls to interact with Oracle on Solaris. Oracle version is 8.1.6. When the following query:

"select col1 from tab1 where n=?"

is executed via ODBC with 'xyz' to the bind variable, it causes the following packet transaction over the network(obtained from sniffing packets at Oracle server on port 1521)

1. Connection establishment packets between ODBC client and Oracle server
2. Request(TNS) from ODBC client with the data "select col1 from tab1 where n=:P0......" Note that no value has been sent for the bind variable.
3. Response(TNS) from Oracle server with no data for the request sent in step 2.
4. Request(TNS) from ODBC client with the data "select col1 from tab1 where n=:P0 xyz"
5. Response(TNS) from Oracle server with valid data for the request sent in step 4. [...]

Why a dummy TNS request in step 2 is being sent from ODBC ? Is there anything that could cause this scenario in OCI(ODBC driver which I am using is written in OCI) ?

Has any one observed this behavior earlier ? Any ideas to overcome ?

Thanks,
Srinivas. Received on Thu Apr 03 2003 - 03:22:55 CST