OCI threaded sample causes ORA-00022 or ORA-01001

Question

I have created a sample program which initializes environment in OCI_THREADED mode and then starts multiple threads. Usually it completes successfully, but sometimes it terminates with error ORA-00022 (invalid session ID; access denied) or ORA-01001 (invalid cursor). I have checked with Oracle 9.2 and 10.2, problem occurs on both. Do I something wrong in my code ? My code requires creation of record rec1 (id number primary key, val number) containing rows with id equal to 0 .. 100:
#include <pthread.h>
#include <oci.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
static char g_User, g_Pass;
static OCIEnv *g_pOciEnv = NULL;
static OCIError *g_pOciError = NULL;
static OCIServer *g_pOciServer = NULL;
enum { NUM_THR = 20, NUM_INC = 30 };
typedef struct {
OCIError *pOciError;
OCISession *pOciSession;
OCISvcCtx *pOciSvcCtx;
} OciSession;
static void CheckError(OCIError *pOciError, sword status)
OraText errbuf[512];
sb4 errcode;
int i;
if( status != OCI_SUCCESS ) {
fflush(stdout);
if( status == OCI_ERROR ) {
for(i = 1; OCIErrorGet(pOciError, (ub4) i, NULL, &errcode,
errbuf, (ub4)sizeof(errbuf), OCI_HTYPE_ERROR) ==
OCI_SUCCESS; ++i)
fprintf(stderr, "Error: %s\n", errbuf);
}else
fprintf(stderr, "unexpected error %d\n", (int)status);
exit(1);
static void InitSession(OciSession *pSes)
OCIHandleAlloc((dvoid *)g_pOciEnv, (dvoid **)&pSes->pOciError,
OCI_HTYPE_ERROR, 0, NULL);
CheckError(pSes->pOciError, OCIHandleAlloc((dvoid*)g_pOciEnv,
(dvoid**)&pSes->pOciSession, OCI_HTYPE_SESSION, 0, NULL));
CheckError(pSes->pOciError, OCIAttrSet((dvoid *)pSes->pOciSession,
OCI_HTYPE_SESSION, g_User, strlen(g_User), OCI_ATTR_USERNAME,
pSes->pOciError));
CheckError(pSes->pOciError, OCIAttrSet((dvoid *)pSes->pOciSession,
OCI_HTYPE_SESSION, g_Pass, strlen(g_Pass), OCI_ATTR_PASSWORD,
pSes->pOciError));
CheckError(pSes->pOciError, OCIHandleAlloc((dvoid *)g_pOciEnv,
(dvoid**)&pSes->pOciSvcCtx, OCI_HTYPE_SVCCTX, 0, NULL));
CheckError(pSes->pOciError, OCIAttrSet((dvoid *)pSes->pOciSvcCtx,
OCI_HTYPE_SVCCTX, (dvoid*)g_pOciServer, 0,
OCI_ATTR_SERVER, pSes->pOciError));
CheckError(pSes->pOciError, OCISessionBegin(pSes->pOciSvcCtx,
pSes->pOciError, pSes->pOciSession, OCI_CRED_RDBMS,
OCI_DEFAULT));
CheckError(pSes->pOciError, OCIAttrSet(pSes->pOciSvcCtx, OCI_HTYPE_SVCCTX,
(dvoid*)pSes->pOciSession, 0, OCI_ATTR_SESSION,
pSes->pOciError));
static void CleanupSession(OciSession *pSes)
CheckError(pSes->pOciError, OCITransRollback(pSes->pOciSvcCtx,
pSes->pOciError, OCI_DEFAULT));
CheckError(pSes->pOciError, OCISessionEnd(pSes->pOciSvcCtx,
pSes->pOciError, pSes->pOciSession, OCI_DEFAULT));
OCIHandleFree(pSes->pOciSession, OCI_HTYPE_SESSION);
OCIHandleFree(pSes->pOciSvcCtx, OCI_HTYPE_SVCCTX);
OCIHandleFree(pSes->pOciError, OCI_HTYPE_ERROR);
static void ThreadFun(void pv)
char sText[] = "select val from rec1 where id = :ses ";
int i, nSes = (int)pv, nVal;
OciSession ses;
OCIStmt *pStmt;
OCIDefine *pODefine = NULL;
OCIBind *pOBind = NULL;
InitSession(&ses);
OCIHandleAlloc(g_pOciEnv, (void**)&pStmt, OCI_HTYPE_STMT, 0, NULL);
CheckError(ses.pOciError, OCIStmtPrepare(pStmt, ses.pOciError,
(OraText*)sText, strlen(sText), OCI_V7_SYNTAX, OCI_DEFAULT));
CheckError(ses.pOciError, OCIBindByName(pStmt, &pOBind,
ses.pOciError, "ses", strlen("ses"), &nSes, sizeof(int),
SQLT_INT, NULL, NULL, NULL,
0, NULL, OCI_DEFAULT));
CheckError(ses.pOciError, OCIDefineByPos(pStmt, &pODefine,
ses.pOciError, 1, &nVal, sizeof(int), SQLT_INT, NULL, NULL,
NULL, OCI_DEFAULT));
for(i = 0; i < NUM_INC; ++i) {
CheckError(ses.pOciError, OCIStmtExecute(ses.pOciSvcCtx, pStmt,
ses.pOciError, 1, 0, NULL, NULL, OCI_DEFAULT));
printf("%d %d\n", nSes, i);
CheckError(ses.pOciError, OCIHandleFree(pStmt, OCI_HTYPE_STMT) );
CleanupSession(&ses);
int main(int argc, char *argv[])
pthread_t thread[NUM_THR];
int i;
if( argc < 3 ) {
printf("usage: %s user password [dblink]\n", argv[0]);
return 0;
g_User = argv[1];
g_Pass = argv[2];
OCIEnvCreate(&g_pOciEnv, OCI_THREADED, NULL, NULL, NULL, NULL, 0, NULL);
OCIHandleAlloc((dvoid *)g_pOciEnv, (dvoid**)&g_pOciError,
OCI_HTYPE_ERROR, 0, NULL);
OCIHandleAlloc((dvoid*)g_pOciEnv, (dvoid**)&g_pOciServer,
OCI_HTYPE_SERVER, 0, NULL);
CheckError(g_pOciError, OCIServerAttach(g_pOciServer, g_pOciError,
(text*)argv[3], argc>3 ? strlen(argv[3]) : 0, OCI_DEFAULT));
for(i = 0; i < NUM_THR; ++i)
pthread_create(thread+i, NULL, ThreadFun, (void*)i);
for(i = 0; i < NUM_THR; ++i)
pthread_join(thread, NULL);
OCIServerDetach(g_pOciServer, g_pOciError, OCI_DEFAULT);
OCIHandleFree(g_pOciServer, OCI_HTYPE_SERVER);
OCIHandleFree(g_pOciEnv, OCI_HTYPE_ENV);
printf("OK\n");
return 0;

Answer 1

In your code the join for thread looks like:
for(i = 0; i < NUM_THR; ++i)
pthread_join(thread, NULL);
is this actually what is there in your code or is it just a typo in posting the message ? If it is the former case then the problem is here itself