Re: Dynamic Shared Memory stuff

On Mon, Apr 14, 2014 at 10:03 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Sat, Apr 12, 2014 at 1:32 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>> I have checked that other place in code also check handle to
>> decide if API has failed. Refer function PGSharedMemoryIsInUse().
>> So I think fix to call GetLastError() after checking handle is okay.
>> Attached patch fixes this issue. After patch, the server shows below
>> log which is exactly what is expected from test_shm_mq
>
> In PostgreSQL code, hmap == NULL, rather than !hmap, is the preferred
> way to test for a NULL pointer. I notice that the !hmap style is used
> throughout this code, so I guess cleaning that up is a matter for a
> separate commit.

I think in that case we might want to cleanup some other similar usage
(PGSharedMemoryCreate) of !hmap.

> For the create case, I'm wondering if we should put the block that
> tests for !hmap *before* the _dosmaperr() and check for EEXIST. What
> is your opinion?

Either way is okay, but I think the way you are suggesting is better as it
will make code consistent with other place (PGSharedMemoryCreate()).

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com