Re: [Dev-C++] (OT:) SQLExecDirect fails on good statements

[Per W. <pw...@ia...>]

I would suspect either your threaded code, or that you are not linking
with a thread-safe library.

/Per W

On Sat, 25 Oct 2003, Ed Cottrell wrote:

> Hi all,
>
> This is probably going to be too abstract to get an answer, but here goes:
> in an application I'm working on, lots (usually thousands) of database
> queries are issued of the form
>
> "SELECT division_id FROM my_db.my_table WHERE division='var1' and
> division_id = var2"
>
> I'm building these queries using sprintf(), then running them with
> SQLExecDirect; about 99.98% of the time, this works perfectly. The remaining
> .02% of queries will fail, randomly. For example, the query "SELECT
> division_id FROM my_db.my_table WHERE division='FOO' and division_id = 1"
> will work almost every time, but fail .02% of the time.
>
> These queries are being created and executed by (a user-defined number of)
> threads, but not asynchronously, and the database server is not having any
> problems. As I've said, the failures are not on (or immediately) following
> specific queries, but seem to be randomly distributed throughout the
> thousands of queries being executing. I put in a little error check, so that
> if SQLExecDirect does not return SQL_SUCCESS, I get a display of the failed
> query, and I can verify that the data is not being corrupted, I don't have
> any buffer overflows, etc. The database server is MySQL-max-nt.
>
> I'm sorry, but I can't post full source code, for various reasons. I'm just
> wondering if anybody knows why perfectly valid SQL statements would fail,
> once in every 5,000 tries, when the server itself is not being overwhelmed.
>
> -Ed
>