Re: [PATCH] Use MAP_HUGETLB where supported (v3)

On Wed, Oct 30, 2013 at 12:17 PM, Alvaro Herrera
<alvherre(at)2ndquadrant(dot)com> wrote:
>> > I wasn't talking about a built-in support. It was about an ability (a
>> > way) to back sh_buf with hugepages.
>>
>> Then what you need is to set
>> dynamic_shared_memory_type = sysv
>> in postgresql.conf.
>
> The above is mistaken -- there's no way to disable the mmap() segment in
> 9.3, other than recompiling with EXEC_BACKEND which is probably
> undesirable for other reasons.

Alternatively, I assume it could be linked with libhugetlbfs and you
don't need any source modifications in this case. However I am not
sure it will work with shared memory.

> I don't think I had ever heard of that recipe to use huge pages in
> previous versions; since the win is probably significant in some
> systems, we could have made this configurable.

There are several articles in the web describing how to do this,
except the mine one. And the win becomes mostly significant when you
have 64GB and more on your server.

--
Kind regards,
Sergey Konoplev
PostgreSQL Consultant and DBA

http://www.linkedin.com/in/grayhemp
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