OCI with a Multithreading App

From: David Murphy <davidmurphy7799_at_my-deja.com>
Date: 2000/06/18
Message-ID: <8iitvm$4jq$1@nnrp1.deja.com>#1/1

Hi - I am trying to figure out how to initialize OCI so that threads in a multithreaded app do not block each other.

The app creates threads T1, T2 both of which connect to the Oracle database to perform SQL.
T1 connects and starts processing SQL insert and selects. T2 starts and connects OK - however at this
point T2 tries to process its SQL statements but ends up blocked, waiting for T1. When T1 finsishes T2 starts it processsing.

So the question is how to allow T1 and T2 to operate without blocking. Both T1 and T2 have created their own
OCI Environment handle and login under that handle. The handle is created with OCIEnvCreate with OCI_DEFAULT as the mode. They also have their own error and service context handles.

When I tried OCI_THREADED as the mode for the OCIEnvCreate I get a access violation when disconnecting T1.
Its not clear from the OCI doc whether I need to specify OCI_THREADED as the mode
in OCIEnvCreated - anyone know about this?

I also tried to have T1 and T2 share the same OCI Environment handle. With OCI_DEFAULT T1 blocked T2.
With OCI_THREADED I get the same access violation.

The Ora doc is on this is confusing to say the least.. Any help much appreciated.

Regards
David Murphy
NetDirect_at_compuserve.com

The sequence of calls for each thread is ..

OCIEnvCreate(&OCIEnvHandle, OCI_DEFAULT /*OCI_THREADED*/ ,

                          NULL, NULL, NULL, NULL, 0, NULL);
OCIHandleAlloc((dvoid *) OCIEnvHandle,
      (dvoid **) &OCIErrorHandle,
      (ub4) OCI_HTYPE_ERROR,
      (size_t) 0, (dvoid **) 0);

OCILogon((OCIEnv *) OCIEnvHandle, OCIErrorHandle, &OCISvcHandle, ..)

OCIHandleAlloc((dvoid *)pConnection->OCIEnvHandle, (dvoid **) &OCIStatementHandle,

                           (ub4)OCI_HTYPE_STMT, (CONST size_t) 0,

(dvoid **) 0);

OCIStmtExecute(pConnection->OCISvcHandle,

                             OCIStatementHandle,
                             pConnection->OCIErrorHandle,


                             (ub4) nIterations,

                             (ub4) 0,

                             (OCISnapshot *) NULL,

                             (OCISnapshot *) NULL,

                             (ub4) OCI_DEFAULT);

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Before you buy. Received on Sun Jun 18 2000 - 00:00:00 CDT