RE: Race condition in Oracle C Interface?

From: Mohan, Ross <MohanR_at_STARS-SMI.com>
Date: Mon, 20 Nov 2000 10:31:00 -0500
Message-Id: <10686.122501@fatcity.com>

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The client locks up you believe?

It would be interesting to run
it under Un*x, just to see if the
same thing happens.

Could be an NT threading thing, there
are some performance issues with older
versions of NT and small thread scheduling...

just a thought

Ross Mohan

-----Original Message-----

From: Michael Haggerty [mailto:mhagger_at_alum.mit.edu] Sent: Sunday, November 19, 2000 6:00 PM
To: Multiple recipients of list ORACLE-L Subject: Race condition in Oracle C Interface?

I am trying to use Oracle in a multithreaded application that creates and destroys multiple database connections. It seems to have tickled a bug in Oracle, though, because the application hangs up deep in Oracle. I simplified the application into the trivial C program appended below, which on my system locks up about half of the time. It just opens up two database connections and some associated structures and then closes them. I don't think there is a problem with code, but if you are sceptical just take a look; it is quite trivial.

Has anybody seen this problem? Does anyone know a workaround?

I am running Oracle 8.1.6.1 under Linux/Intel with kernel version 2.2.14. The program locks up within OCIServerDetach and has to be kill -6'ed or stronger. Only the client seems to lock up; the server seems unaffected.

Thanks,
Michael

--

Michael Haggerty
mhagger_at_alum.mit.edu

/* ==================== main.c ======================== */

/* compile with:

    gcc -I/ora8/m01/app/oracle/product/8.1.6/rdbms/demo


-I/ora8/m01/app/oracle/product/8.1.6/network/public

-I/ora8/m01/app/oracle/product/8.1.6/plsql/public

-I/ora8/m01/app/oracle/product/8.1.6/rdbms/public -DORACLE8i -g -o main

-L/ora8/m01/app/oracle/product/8.1.6/lib/ -lclntsh
-Wl,-rpath,/ora8/m01/app/oracle/product/8.1.6/lib ./main.c

#include <assert.h>
#include <stdio.h>
#include <string.h>
#include <malloc.h>
#include <oci.h>


typedef struct {
	OCIEnv		*envhp;			/* Environment handle 	*/
	OCIError	*errhp;			/* Error handle		*/
	OCIServer	*srvhp;			/* Server handle	*/
	OCISession	*usrhp;			/* User handle		*/
	OCISvcCtx	*svchp;			/* Service Context	*/

} ServerContext;

ServerContext *Connect(char *user, char *password, char *database) {

	ServerContext *sc;
	int	userlen;
	int	passwordlen;
	int	databaselen;
	sword	status;
	sword	credentials = OCI_CRED_RDBMS;

        userlen = strlen(user);
        passwordlen = strlen(password);
        databaselen = strlen(database);

        sc = (ServerContext *)malloc(sizeof(ServerContext));

	sc->envhp = NULL;
	sc->errhp = NULL;
	sc->svchp = NULL;
	sc->srvhp = NULL;
	sc->usrhp = NULL;

	status = OCIEnvCreate(&sc->envhp, OCI_THREADED, NULL, NULL, NULL,
NULL,
                              0, NULL);
	assert(status == OCI_SUCCESS);

	/* Allocate the error handle */
	status = OCIHandleAlloc(sc->envhp, (dvoid **)&sc->errhp,
                                OCI_HTYPE_ERROR, 0, NULL);
	assert(status == OCI_SUCCESS);

	/* Allocate the server handle */
	status = OCIHandleAlloc(sc->envhp, (dvoid **) &sc->srvhp,
                                OCI_HTYPE_SERVER, 0, NULL);
	assert(status == OCI_SUCCESS);

	/* Connect to database */
	status = OCIServerAttach(sc->srvhp, sc->errhp, database,
databaselen,
                                 OCI_DEFAULT);
	assert(status == OCI_SUCCESS);

	/* Allocate a service context */
	status = OCIHandleAlloc(sc->envhp, (dvoid **) &sc->svchp,
                                OCI_HTYPE_SVCCTX, 0, NULL);
	assert(status == OCI_SUCCESS);

	/* Attach the server to the service context */
	status = OCIAttrSet(sc->svchp, OCI_HTYPE_SVCCTX, (dvoid *)
sc->srvhp,
                            (ub4) 0, OCI_ATTR_SERVER, sc->errhp);
	assert(status == OCI_SUCCESS);

	/* Allocate a session */
	status = OCIHandleAlloc(sc->envhp, (dvoid **) &sc->usrhp,
                                OCI_HTYPE_SESSION, 0, NULL);
	assert(status == OCI_SUCCESS);

	/* Were credentials provided? if so, set them in the session */
        status = OCIAttrSet(sc->usrhp, OCI_HTYPE_SESSION,
                            (dvoid *) user, (ub4) userlen,
                            OCI_ATTR_USERNAME, sc->errhp);
        assert(status == OCI_SUCCESS);

        status = OCIAttrSet(sc->usrhp, OCI_HTYPE_SESSION,
                            (dvoid *) password, (ub4) passwordlen,
                            OCI_ATTR_PASSWORD, sc->errhp);
        assert(status == OCI_SUCCESS);
	
	/* Now begin the session */
	status = OCISessionBegin(sc->svchp, sc->errhp, sc->usrhp,
                                 credentials, OCI_DEFAULT);
	assert(status == OCI_SUCCESS);

	/* Now attach the session to the service context */
	status = OCIAttrSet(sc->svchp, OCI_HTYPE_SVCCTX,
                            sc->usrhp, 0, OCI_ATTR_SESSION, sc->errhp);
	assert(status == OCI_SUCCESS);

	return sc;

}

/*
** ServerContext_dealloc
**
** Called when a server context goes out of scope; hang up the connection
** to the database!

void ServerContext_dealloc(ServerContext *self) {

sword status;

	/* End the session */
	assert(self->svchp);
        status = OCISessionEnd(self->svchp, self->errhp, self->usrhp,
                               OCI_DEFAULT);
        assert(status == OCI_SUCCESS);

	/* Disconnect from the server */
	assert(self->srvhp);
        status = OCIServerDetach(self->srvhp, self->errhp, OCI_DEFAULT);
        assert(status == OCI_SUCCESS);

	/* Deallocate the session handle */
        assert(self->usrhp);
        status = OCIHandleFree(self->usrhp, OCI_HTYPE_SESSION);
        assert(status == OCI_SUCCESS);

	/* Deallocate the server handle */
        assert(self->srvhp);
        status = OCIHandleFree(self->srvhp, OCI_HTYPE_SERVER);
        assert(status == OCI_SUCCESS);

	/* Deallocate the service context handle */
	assert(self->svchp);
        status = OCIHandleFree(self->svchp, OCI_HTYPE_SVCCTX);
        assert(status == OCI_SUCCESS);

	/* Deallocate the error handle */
        assert(self->errhp);
        status = OCIHandleFree(self->errhp, OCI_HTYPE_ERROR);
        assert(status == OCI_SUCCESS);

	/* Deallocate the environment handle */
        assert(self->envhp);
        status = OCIHandleFree(self->envhp, OCI_HTYPE_ENV);
        assert(status == OCI_SUCCESS);

        free(self);

}

int main(int argc, char *argv[]) {

    char *user;
    char *password;
    char *database;

    ServerContext *db1;
    ServerContext *db2;
    assert(argc == 4);
    user = argv[1];
    password = argv[2];
    database = argv[3];
    db1 = Connect(user, password, database);     db2 = Connect(user, password, database);     fprintf(stderr, "Deleting db2.\n");
    ServerContext_dealloc(db2);
    fprintf(stderr, "Deleting db1.\n");
    ServerContext_dealloc(db1);
    fprintf(stderr, "This line often not reached.\n");     return 0;
}

--

Please see the official ORACLE-L FAQ: http://www.orafaq.com
--

Author: Michael Haggerty
INET: mhagger_at_alum.mit.edu

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
San Diego, California        -- Public Internet access / Mailing Lists


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The client locks up you believe?

<P><FONT SIZE=3D2>It would be interesting to run</FONT>
<BR><FONT SIZE=3D2>it under Un*x, just to see if the</FONT>
<BR><FONT SIZE=3D2>same thing happens. </FONT>
</P>

<P><FONT SIZE=3D2>Could be an NT threading thing, there</FONT>
<BR><FONT SIZE=3D2>are some performance issues with older</FONT>

versions of NT and small thread scheduling...

just a thought

- Ross Mohan

-----Original Message----- From: Michael Haggerty [<A = HREF=3D"mailto:mhagger_at_alum.mit.edu">mailto:mhagger_at_alum.mit.edu</A>]</F=

ONT>
<BR><FONT SIZE=3D2>Sent: Sunday, November 19, 2000 6:00 PM</FONT>
<BR><FONT SIZE=3D2>To: Multiple recipients of list ORACLE-L</FONT>
<BR><FONT SIZE=3D2>Subject: Race condition in Oracle C =

Interface?

I am trying to use Oracle in a multithreaded = application that creates
 and destroys multiple database connections.  It = seems to have tickled
 a bug in Oracle, though, because the application = hangs up deep in
 Oracle.  I simplified the application into the = trivial C program
 appended below, which on my system locks up about = half of the time.
 It just opens up two database connections and some = associated
 structures and then closes them.  I don't think = there is a problem
 with code, but if you are sceptical just take a = look; it is quite
 trivial.

Has anybody seen this problem?  Does anyone know = a workaround?

I am running Oracle 8.1.6.1 under Linux/Intel with = kernel version
 2.2.14.  The program locks up within = OCIServerDetach and has to be
 kill -6'ed or stronger.  Only the client seems = to lock up; the server
 seems unaffected.

<P><FONT SIZE=3D2>Thanks,</FONT>
<BR><FONT SIZE=3D2>Michael</FONT>
</P>

<P><FONT SIZE=3D2>--</FONT>
<BR><FONT SIZE=3D2>Michael Haggerty</FONT>

mhagger_at_alum.mit.edu

<P><FONT SIZE=3D2>/* =
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D main.c =
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=

*/

/* compile with:

gcc =
-I/ora8/m01/app/oracle/product/8.1.6/rdbms/demo =
-I/ora8/m01/app/oracle/product/8.1.6/network/public =
-I/ora8/m01/app/oracle/product/8.1.6/plsql/public =
-I/ora8/m01/app/oracle/product/8.1.6/rdbms/public -DORACLE8i -g -o main =
-L/ora8/m01/app/oracle/product/8.1.6/lib/ -lclntsh =
-Wl,-rpath,/ora8/m01/app/oracle/product/8.1.6/lib ./main.c

*/

<P><FONT SIZE=3D2>#include &lt;assert.h&gt;</FONT>
<BR><FONT SIZE=3D2>#include &lt;stdio.h&gt;</FONT>
<BR><FONT SIZE=3D2>#include &lt;string.h&gt;</FONT>
<BR><FONT SIZE=3D2>#include &lt;malloc.h&gt;</FONT>
<BR><FONT SIZE=3D2>#include &lt;oci.h&gt;</FONT>
</P>
<BR>

typedef struct {         OCIEnv          = *envhp;         =         /* Environment handle   = */
         OCIError        *errhp; =

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /* Error handle =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; */</FONT>

<FONT =

SIZE=3D2>OCIServer&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; *srvhp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /* Server =
handle&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; */</FONT>

OCISession      *usrhp; =

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /* User handle&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; */</FONT>

<FONT =

SIZE=3D2>OCISvcCtx&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; *svchp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; /* Service =

Context      */

<BR><FONT SIZE=3D2>} ServerContext;</FONT>
</P>
<BR>

ServerContext *Connect(char *user, char *password, = char *database) {
         ServerContext *sc;
         int     userlen;         int     passwordlen;         int     databaselen;

<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT =
SIZE=3D2>sword&nbsp;&nbsp; status;</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT =

SIZE=3D2>sword   credentials =3D OCI_CRED_RDBMS;

userlen = =3D strlen(user);
         = passwordlen =3D strlen(password);         = databaselen =3D strlen(database);

sc =3D = (ServerContext *)malloc(sizeof(ServerContext));

<FONT =

SIZE=3D2>sc-&gt;envhp =3D NULL;</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT =
SIZE=3D2>sc-&gt;errhp =3D NULL;</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT =
SIZE=3D2>sc-&gt;svchp =3D NULL;</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT =
SIZE=3D2>sc-&gt;srvhp =3D NULL;</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT =
SIZE=3D2>sc-&gt;usrhp =3D NULL;</FONT>

status =3D = OCIEnvCreate(&sc->envhp, OCI_THREADED, NULL, NULL, NULL, = NULL,
 <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 0, NULL);</FONT>

assert(status =3D=3D OCI_SUCCESS);

/* = Allocate the error handle */
         status = =3D OCIHandleAlloc(sc->envhp, (dvoid **)&sc->errhp, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OCI_HTYPE_ERROR, 0, =

NULL);
         assert(status =3D=3D OCI_SUCCESS);

/* = Allocate the server handle */
         status = =3D OCIHandleAlloc(sc->envhp, (dvoid **) &sc->srvhp, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OCI_HTYPE_SERVER, =

0, NULL);
         assert(status =3D=3D OCI_SUCCESS);

/* Connect = to database */
         status = =3D OCIServerAttach(sc->srvhp, sc->errhp, database, = databaselen,
 <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =

OCI_DEFAULT);
         assert(status =3D=3D OCI_SUCCESS);

/* = Allocate a service context */
         status = =3D OCIHandleAlloc(sc->envhp, (dvoid **) &sc->svchp, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OCI_HTYPE_SVCCTX, =

0, NULL);
         assert(status =3D=3D OCI_SUCCESS);

/* Attach = the server to the service context */         status = =3D OCIAttrSet(sc->svchp, OCI_HTYPE_SVCCTX, (dvoid *) = sc->srvhp,
 <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp; (ub4) 0, OCI_ATTR_SERVER, =

sc->errhp);
         assert(status =3D=3D OCI_SUCCESS);

/* = Allocate a session */
         status = =3D OCIHandleAlloc(sc->envhp, (dvoid **) &sc->usrhp, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OCI_HTYPE_SESSION, =

0, NULL);
         assert(status =3D=3D OCI_SUCCESS);

/* Were = credentials provided? if so, set them in the session */         status = =3D OCIAttrSet(sc->usrhp, OCI_HTYPE_SESSION, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp; (dvoid *) user, (ub4) userlen,</FONT>

<FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp; OCI_ATTR_USERNAME, sc-&gt;errhp);</FONT>

= assert(status =3D=3D OCI_SUCCESS);

status =3D = OCIAttrSet(sc->usrhp, OCI_HTYPE_SESSION, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp; (dvoid *) password, (ub4) =

passwordlen,
 <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp; OCI_ATTR_PASSWORD, sc-&gt;errhp);</FONT>

=

assert(status =3D=3D OCI_SUCCESS);</FONT>
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;=20
<BR>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <FONT SIZE=3D2>/* Now =

begin the session */
         status = =3D OCISessionBegin(sc->svchp, sc->errhp, sc->usrhp, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; credentials, =

OCI_DEFAULT);
         assert(status =3D=3D OCI_SUCCESS);

/* Now = attach the session to the service context */         status = =3D OCIAttrSet(sc->svchp, OCI_HTYPE_SVCCTX, <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp; sc-&gt;usrhp, 0, OCI_ATTR_SESSION, =

sc->errhp);
         assert(status =3D=3D OCI_SUCCESS);

return = sc;
 }

<P><FONT SIZE=3D2>/*</FONT>
<BR><FONT SIZE=3D2>** ServerContext_dealloc</FONT>
<BR><FONT SIZE=3D2>**</FONT>
<BR><FONT SIZE=3D2>** Called when a server context goes out of scope; =

hang up the connection

<BR><FONT SIZE=3D2>** to the database!</FONT>
<BR><FONT SIZE=3D2>*/</FONT>
</P>

void ServerContext_dealloc(ServerContext *self) = {
         sword = status;

/* End the = session */
         assert(self->svchp);
         status = =3D OCISessionEnd(self->svchp, self->errhp, = self->usrhp,
 <FONT =

SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nb=
sp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; OCI_DEFAULT);</FONT>

= assert(status =3D=3D OCI_SUCCESS);

/* = Disconnect from the server */
         assert(self->srvhp);
         status = =3D OCIServerDetach(self->srvhp, self->errhp, = OCI_DEFAULT);
         = assert(status =3D=3D OCI_SUCCESS);

/* = Deallocate the session handle */
         = assert(self->usrhp);
         status = =3D OCIHandleFree(self->usrhp, OCI_HTYPE_SESSION);         = assert(status =3D=3D OCI_SUCCESS);

/* = Deallocate the server handle */
         = assert(self->srvhp);
         status = =3D OCIHandleFree(self->srvhp, OCI_HTYPE_SERVER);         = assert(status =3D=3D OCI_SUCCESS);

/* = Deallocate the service context handle */         assert(self->svchp);
         status = =3D OCIHandleFree(self->svchp, OCI_HTYPE_SVCCTX);         = assert(status =3D=3D OCI_SUCCESS);

/* = Deallocate the error handle */
         = assert(self->errhp);
         status = =3D OCIHandleFree(self->errhp, OCI_HTYPE_ERROR);         = assert(status =3D=3D OCI_SUCCESS);

/* = Deallocate the environment handle */         = assert(self->envhp);

<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; status =
=3D OCIHandleFree(self-&gt;envhp, OCI_HTYPE_ENV);</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; =

assert(status =3D=3D OCI_SUCCESS);

= free(self);
 }

<P><FONT SIZE=3D2>int main(int argc, char *argv[]) {</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; char *user;</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; char *password;</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; char *database;</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; ServerContext *db1;</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; ServerContext *db2;</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; assert(argc =3D=3D 4);</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; user =3D argv[1];</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; password =3D argv[2];</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; database =3D argv[3];</FONT>
<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; db1 =3D Connect(user, password, =

database);
     db2 =3D Connect(user, password, = database);
     fprintf(stderr, "Deleting = db2.\n");
     =
ServerContext_dealloc(db2);
     fprintf(stderr, "Deleting = db1.\n");
     =
ServerContext_dealloc(db1);
     fprintf(stderr, "This line = often not reached.\n");

<BR><FONT SIZE=3D2>&nbsp;&nbsp;&nbsp; return 0;</FONT>
<BR><FONT SIZE=3D2>}</FONT>
</P>

-- 
 Please see the official ORACLE-L FAQ: <A = HREF=3D"http://www.orafaq.com" =
TARGET=3D"_blank">http://www.orafaq.com</A>

<BR><FONT SIZE=3D2>-- </FONT>
<BR><FONT SIZE=3D2>Author: Michael Haggerty</FONT>
<BR><FONT SIZE=3D2>&nbsp; INET: mhagger_at_alum.mit.edu</FONT>
</P>

Fat City Network Services    -- (858) = 538-5051  FAX: (858) 538-5051 San Diego, =
California        -- Public Internet = Received on Mon Nov 20 2000 - 09:31:00 CST