Re: About OCI thread safety

> > Pass a value of OCI_DEFAULT to OCIEnvCreate(). In this case, the OCI
> > library automatically gets a mutex on every OCI call on the same
> > environment handle."
>
>I think it should be OCI_THREADED and not OCI_DEFAULT. OCI_THREADED >mode would automatically acquire and manage mutexing.
May be it's a typo, but if it is, I stuill don't understand what they say. The complete section with its context is : "
The following three scenarios are possible, depending on how many connections exist in each environment handle, and how many threads will be spawned in each connection.
1 - If an application has multiple environment handles, but each only has one thread (one session exists in each environment handle), no mutexing is required.
2 - If an application running in OCI_THREADED mode maintains one or more environment handles, each of which has multiple connections, it also has the following options:
2.1 Pass a value of OCI_NO_MUTEX for the mode of OCIEnvCreate(). In this case the pplication must mutex OCI calls by made on the same environment handle itself. This has the advantage that the mutexing scheme can be optimized based on the application design. The programmer must also insure that only one OCI call is in process on the environment handle connection at any given time. 2.2 Pass a value of OCI_DEFAULT to OCIEnvCreate(). In this case, the OCI library automatically gets a mutex on every OCI call on the same environment handle.
"
If you're right, we should read for 2.2 :"Pass a value of OCI_THREADED...". But 2 says that the "application is running in OCI_THREADED mode". Is there any other way to set a threaded mode tgan to pass OCI_THREADED to OCIEnvCreate() ???

> > Users who do not write multithreaded programs do not pay a performance
> > penalty for using thread-safe OCI calls."
>
> Yes! It simply means that the threading feature will not affect somebody
> whos writing a non-threaded application, taken that the environment is
> created in the OCI_DEFAULT mode.
>

But OCI_DEFAULT is not a "thread safe OCI call" : it does not manage mutexes. Or is there any other way to be thread safe ???

> > And a few lines below :
> > "If an application is single-threaded, whether or not the platform is
> > thread-safe, the application should pass a value of OCI_DEFAULT to
> > OCIInitialize() or OCIEnvCreate(). Single-threaded applications which
> > run in OCI_THREADED mode may incur performance hits."
> >
> > So what ??????
>
> Yes! The application would incur a performance hit because it's single
> threaded and still uses OCI_THREADED as the mode. Think of all the
> unnecessary mutexing.
>

You're right, this one is obvious. Of course, as I am not an english native speaker, I might have misunderstood some sentences. But, in the way I undestand it, it seems to me that this documentation is inconsistent.

Thanks for replying anyway. I don't ask these questions just to split hairs. I'm really and heavily stuck on memory and thread bogues in an OCI application, and I'm looking for all information able to help me to get out of this... ;o) Received on Wed Apr 26 2006 - 07:14:43 CDT