List:MySQL ODBC« Previous MessageNext Message »
From:Michael Widenius Date:September 8 1999 8:58am
Subject:Re: Problems with ColdFusion and MyODBC
View as plain text  
>>>>> "Scott" == Scott Weikart <scott@stripped> writes:

Scott> Replying to my own message...
>>> In looking over our problems with Cold Fusion, it appears that MyODBC is
>>> singlethreaded.
>> 
>> Here's the MyODBC maintainer's comments on threads:
>> 
Ales> Hello,
Ales> is libmyodbc thread safe or I should wrap ODBC functions with mutexes?
Ales> I wrote a simple test program where 2 threads share ODBC environment
Ales> and connection and within their bodies thay keep running in loop doing
Ales> SQLAllocStmt,SQLExecDirect,SQLBindCol,SQLFetch and SQLFreeStmt. It
Ales> crashes within tens
Ales> of seconds. However, if I wrap SQLExecDirect with a mutex then the
>> test
Ales> seems to run
Ales> without problems. Where can I find out which functions from libmyodbc
>> are
Ales> safe to use directly within a multithreaded program?
>> 
>> The MyODBC is thread safe if you use different connections.  If two
>> threads access the same connection at the same time anything can
>> happen!
>> 
>> As MyODBC reads all results sets into memory, it 'should' be thread safe
>> if you have a mutex around SQLExecDirect.
>> 
>> Regards,
>> Monty

Scott> This makes me wonder whether it would be possible/desirable to put a mutex
Scott> around SQLExecDirect *inside* MyODBC.  So that threaded applications using
Scott> MyODBC would always work.

Yes, this would be possible (and I have this on my TODO).  On problem 
is of course that if the application is not using different
connections, it will not get more performance by using
threads.

Regards,
Monty
Thread
Problems with ColdFusion and MyODBCScott Weikart5 Sep
Re: Problems with ColdFusion and MyODBCScott Weikart5 Sep
Re: Problems with ColdFusion and MyODBCScott Weikart5 Sep
  • Re: Problems with ColdFusion and MyODBCMichael Widenius8 Sep
Re: Problems with ColdFusion and MyODBCScott Weikart5 Sep
  • Re: Problems with ColdFusion and MyODBCMichael Widenius8 Sep
Re: Problems with ColdFusion and MyODBCScott Weikart8 Sep
  • Re: Problems with ColdFusion and MyODBCMichael Widenius8 Sep