Re: My ODBC concurrent Queries

Hi Armin,
No, the n threads use different connections,

And Yes, the codebase is the same for Windows & Linux.

BTW, additional information, from windows client connecting Windows & Linux
MySQL Servers, this problem doesn't arise. But only with Linux clients
connecting to Windows or Linux MySQL Servers, this problem arises,

I am trying to prepare a testcase out of this, and will put it up shortly,
do let me know if I have missed something,

Regards,
Jay


2009/5/25 Armin Schöffmann <[email protected]>

> Hi,
> tell us a few more implementation details on your app:
> In particular, do your n threads share one common db-connection?
> Do you use the same codebase for win & linux?
>
> armin.
>
>
> > -----Original Message-----
> > From: J Jayavasanthan [mailto:[email protected]]
> > Sent: Monday, May 25, 2009 12:50 PM
> > To: [email protected]
> > Subject: My ODBC concurrent Queries
> >
> > Hi,
> > In my application, the mysql server is connected via ODBC and we run
> > multiple threads executing multiple queries with the mysql server.
> > There is
> > an issue in our application when we execute a bulk query (more than
> > 100,000
> > rows in resultset) and when the query takes a longer time for execute,
> > all
> > the other threads seem to just hang on their db operations.
> >
> > We are even unable to get past the 'use database' query in most cases
> > from
> > other threads. Is this a limitation on the ODBC implementation in linux
> > or
> > have we failed to turn-on any options while building our ODBC drivers,
> > do
> > let us know.
> >
> > In Windows, we are able to execute simultaneous queries using ODBC.
> > This
> > test environment uses all pre-compiled binaries from MySQL website.
> >
> > In Linux, we are facing the above issues
> >
> > Linux Flavor - Cent OS 5.2
> > MySQL Server version - 5.1.30
> > unixODBC version - 2.2.11
> > myODBC version - 3.51.27
> >
> > All Linux binaries are compiled in the same system as they are running.
> >
> > When we execute two queries as separate processes (same executable
> > started
> > as different processes), we are able to do so. But, when we create two
> > separate threads within the same process, then the above hang up
> > arises. Is
> > there any particular option in building our application we have missed,
> > do
> > let us know,
> >
> > Regards,
> > Jayavasanthan J
>



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