Re: dynamic shared memory

On Mon, Oct 14, 2013 at 5:11 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Sun, Oct 13, 2013 at 3:07 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>> 1. Do you think we should add information about pg_dynshmem file at link:
>> http://www.postgresql.org/docs/devel/static/storage-file-layout.html
>> It contains information about all files/folders in data directory
>>
>> 2.
>> +/*
>> + * Forget that a temporary file is owned by a ResourceOwner
>> + */
>> +void
>> +ResourceOwnerForgetDSM(ResourceOwner owner, dsm_segment *seg)
>> +{
>>
>> Above function description should use 'dynamic shmem segment' rather
>> than temporary file.
>> "Forget that a dynamic shmem segment is owned by a ResourceOwner"
>
> Good catches, will fix.

During test, I found one issue in Windows implementation.

During startup, when it tries to create new control segment for
dynamic shared memory, it loops until an unused identifier is found,
but for Windows implementation (dsm_impl_windows()), it was returning
error for EEXIST. This error will convert into FATAL as it is during
postmaster startup and will not allow server to start.

Please find attached patch to fix the problem.

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