Re: Q:Thread safe Oracle client library

From: Thomas Kyte <tkyte_at_us.oracle.com>
Date: Thu, 04 Mar 1999 02:04:29 GMT
Message-ID: <36e0e98e.4266174@192.86.155.100>

A copy of this was sent to qing_at_plx.com (if that email address didn't require changing) On Thu, 04 Mar 1999 01:28:39 GMT, you wrote:

>I have read the "developing multi-threaded Application" section of
><<Pro*C/C++ precompiler Programmer's Guide>> I got a question for "Multiple
>Threads Sharing a Single Runtime Context" The document says you cannot share
>a runtime context between multiple threads at the same time if two or more
>threads attempt to use the same runtime context simultaneously, it will give
>the runtime error: SQL-02131: Runtime context in use. I am not sure if that
>is comform to "Thread safe", suppose client should wait to gain access the
>connection instead of give a runtime error..is oracle internally use mutex
>or semaphore? If they do, why they have such a limitation?
>
>

the libs are thread safe in that:

if each thread has its own context (connection) they can all simultaneously work on the database -- each in their own session. the sqllib calls are thread safe and reentrant.
if threads SHARE a context (connection) it is up to you the programmer to ensure that one one thread at a time uses THAT context -- else an error is raised.

the API is thread safe, a connection can only be used by one thread at a time, each thread can work independently of every other thread if it has its own connection.

>-----------== Posted via Deja News, The Discussion Network ==----------
>http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own

Thomas Kyte
tkyte_at_us.oracle.com
Oracle Service Industries
Reston, VA USA

--
http://govt.us.oracle.com/ -- downloadable utilities

Opinions are mine and do not necessarily reflect those of Oracle Corporation Received on Wed Mar 03 1999 - 20:04:29 CST