Re: Supporting huge pages on Windows

On Mon, Jan 30, 2017 at 7:16 AM, Tsunakawa, Takayuki
<tsunakawa(dot)takay(at)jp(dot)fujitsu(dot)com> wrote:
> From: Amit Kapila [mailto:amit(dot)kapila16(at)gmail(dot)com]
>> Hmm. It doesn't work even on a command prompt with administrative
>> privileges. It gives below error:
>>
>> waiting for server to start....2017-01-17 11:20:13.780 IST [4788] FATAL:
>> could not create shared memory segment: error code 1450
>> 2017-01-17 11:20:13.780 IST [4788] DETAIL: Failed system call was
>> CreateFileMap ping(size=148897792,
>> name=Global/PostgreSQL:E:/WorkSpace/PostgreSQL/master/Data)
>> .
>> 2017-01-17 11:20:13.780 IST [4788] LOG: database system is shut down
>> stopped waiting
>> pg_ctl: could not start server
>> Examine the log output.
>>
>>
>> Now, error code 1450 can occur due to insufficient system resources, so
>> I have tried by increasing the size of shared memory (higher value of
>> shared_buffers) without your patch and it works. This indicates some
>> problem with the patch.
>
> Hmm, the large-page requires contiguous memory for each page, so this error could occur on a long-running system where the memory is heavily fragmented. For example, please see the following page and check the memory with RAMMap program referred there.
>

I don't have RAMMap and it might take some time to investigate what is
going on, but I think in such a case even if it works we should keep
the default value of huge_pages as off on Windows. I request somebody
else having access to Windows m/c to test this patch and if it works
then we can move forward.

> http://blog.dbi-services.com/large-pages-and-memory_target-on-windows/
>
> BTW, is your OS or PostgreSQL 32-bit?
>

both 64-bit.

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