Re: Retain dynamic shared memory segments for postmaster lifetime

On Mon, Mar 10, 2014 at 9:48 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> On Mon, Mar 10, 2014 at 8:18 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> I took a look at this patch.  It seems to me that it doesn't do a very
>> good job maintaining the abstraction boundary between what the dsm.c
>> layer knows about and what the dsm_impl.c layer knows about.  However,
>> AFAICS, these problems are purely cosmetic, so I took a crack at
>> fixing them.  I retitled the new implementation-layer function to
>> dsm_impl_keep_segment(), swapped the order of the arguments for
>> consistency with other code, adjusted the dsm_impl.c code slightly to
>> avoid assuming that only the Windows implementation works on Windows
>> (that's currently true, but we could probably make the mmap
>> implementation work there as well), and retooled some of the comments
>> to read better in English.  I'm happy with the attached version but
>> don't have a Windows box to test it there.
>
> Thank you for looking into patch. I have verified that attached patch
> works fine on Windows.
>
> One observation in new version of patch:
>
> + {
> + char name[64];
> +
> + snprintf(name, 64, "%s.%u", SEGMENT_NAME_PREFIX, handle);
> + _dosmaperr(GetLastError());
> + ereport(ERROR,
> + (errcode_for_dynamic_shared_memory(),
> + errmsg("could not duplicate handle: %m")));
> + }

I have updated the patch to change message as below:
errmsg("could not duplicate handle for \"%s\": %m",
           name)));

Let me know your suggestions?


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