Re: BUG #16685: The ecpg thread/descriptor test fails sometimes on Windows

PG Bug reporting form <noreply(at)postgresql(dot)org> writes:
> I found that the get_descriptors() function called in ECPGdeallocate_desc
> sometimes can return null.

> The following debugging code inserted into the ECPGallocate_desc:
> ...
> shows on a failure:
> TlsGetValue() returned null on iteration 209, error: 0, descriptor_key: 28,
> initial descriptor_key: 0.
> or
> TlsGetValue() returned null on iteration: 369, error: 0, descriptor_key: 28,
> initial descriptor_key: 0

Hm. I'm supposing that 0 isn't likely to be the correct TLS index,
and what this is showing us is that we got here before anyone had
done descriptor_key_init.

I'll bet that the correct fix is

static void
set_descriptors(struct descriptor *value)
{
+ pthread_once(&descriptor_once, descriptor_key_init);
pthread_setspecific(descriptor_key, value);
}

and that you could probably reproduce this on non-Windows, too,
if you tried hard (sticking a delay in get_descriptors might do it).

regards, tom lane