Re: [HACKERS] Re: [HACKERS] Re: [HACKERS] Windows service is not starting so there’s message in log: FATAL: "could not create shared memory segment “Global/PostgreSQL.851401618”: Permission denied”

On Tue, Mar 22, 2016 at 2:19 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> On Mon, Mar 21, 2016 at 6:16 PM, Haribabu Kommi <kommi(dot)haribabu(at)gmail(dot)com>
> wrote:
>>
>> On Mon, Mar 14, 2016 at 4:51 PM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
>> wrote:
>> >> Operating system - windows 7
>> >> Binary - PostgreSQL 9.5 (This doesn't matter, 9.4+ can produce the
>> >> problem)
>> >>
>> >> 1. Create two standard users in the system (test_user1 and test_user2)
>> >> 2. Create two databases belongs each user listed above.
>> >> 3. Now using pg_ctl register the services for the two users.
>> >> 4. Provide logon permissions to these users to run the services by
>> >> changing
>> >> service properties.
>> >
>> > Did you mean to say that you changed Log on as: Local System Account in
>> > service properties or something else?
>>
>> No. Not as local service. The user should be the new standard user
>> that is created
>> in the system.
>>
>
> So what do you exactly mean by "Provide logon permissions to these users",
> can you describe in detail what exactly you have done to give those
> permissions. If I try to do with a new user, it gives me error "could not
> open service manager" at start of service.

1. Start the cmd with administrator user and add the new postgresql service
with a standard user that is created.
2. Start the services window with the user having administrator privileges and
go to the corresponding added service.
3. Right click on the service provides an properties option.
4. In the properties, there is an logon tab. Click it
5. Provide the password for the new user that is used for creating the service.
6. This adds the user to log on permissions.

>>
>> >> 5. Now try to start the services, the second service fails with the
>> >> error message.
>> >> 6. Error details can be found out in Event log viewer.
>> >>
>> >
>> > If I follow above steps and do as I mentioned for step-4, I am not able
>> > to
>> > reproduce the issue on Windows-7 m/c using code of HEAD.
>>
>> I am not able to start a service with HEAD code in the same machine, where
>> as it is working for 9.5. I will look into it later and update it.
>>
>
> Okay. But it is confusing for me because you told earlier that you are able
> to reproduce problem in 9.5.

I am able to reproduce the problem with 9.5 binary. I am getting Access Denied
problem when i try to start the 9.6 binary service with the local user.

>> >> Yes, it is working as same user services. The main problem is,
>> >> PostgreSQL
>> >> as a service for two different users in the same system is not working
>> >> because
>> >> of same random getting generated for two services.
>> >>
>> >
>> > I am not sure why you think same random number is problem, as mentioned
>> > above, even if the dsm name is same due to same random number, the code
>> > has
>> > logic to process it appropriately (regenerate the name of dsm). Having
>> > said
>> > that, I don't mean to say that we shouldn't have logic to generate
>> > unique
>> > name and I think we might want to add data dir path to name generation
>> > as we
>> > do for main shared memory, however it is better to first completely
>> > understand the underneath issue.
>>
>> Yes, same random number generation is not the problem. In windows apart
>> from EEXIST error, EACCES also needs to be validated and returned for
>> new random number generation, instead of throwing an error.
>>
>
> Doing the same handling for EACCES doesn't seem to be sane because if EACCES
> came for reason other than duplicate dsm name, then we want to report the
> error instead of trying to regenerate the name. I think here fix should be
> to append data_dir path as we do for main shared memory.

Yes, EACCES may be possible other than duplicate dsm name.

Regards,
Hari Babu
Fujitsu Australia