Re: Threading crash using ODBC

markw wrote:
>
> Here's what I have:
>
> I have an application with 1 main thread and a number of worker threads.
> At startup, I allocate a number of ODBC connections.
> I have an internal queue that is protected by a mutex.
> When one of the worker threads wants to use the database, it gets an un
> occupied SQL connection from the queue.
>
> At startup, I can execte a query just fine. When I try to execute a
> query from one of the worker threads, I get a core dump.
>
> I am using UNIX ODBC and the PostgreSQL driver, as shipped with RedHat 7.3.
>
> The stack trace looks like this:
>
> 0 0x402fba4c in CC_send_query () from /usr/lib/libodbcpsql.so
> (gdb) where
> #0 0x402fba4c in CC_send_query () from /usr/lib/libodbcpsql.so
> #1 0x40314842 in SC_execute () from /usr/lib/libodbcpsql.so
> #2 0x40304c45 in PG_SQLExecute () from /usr/lib/libodbcpsql.so
> #3 0x40304c6b in SQLExecute () from /usr/lib/libodbcpsql.so
> #4 0x402a13f4 in SQLExecute () from /usr/lib/libodbc.so.1
> #5 0x40023d6f in MSqlODBC::ExecResult (this=0x806bfd4,
> sql=0x4037f83c "select value, timeout from msession_sessions where
> session = '2b7atuahma6u9igcorr7c6q8ld7ne86o'") at modbcsql.cpp:360

It's the driver provided by unixODBC itself.
Please inquire unixODBC team about it.
Or try the (maybe) thread-safe driver on *nix
recently provided at http://odbc.postgresql.org/.

regards,
Hiroshi Inoue
http://w2422.nsk.ne.jp/~inoue/