Re: [HACKERS] An attempt to reduce WALWriteLock contention

On 2017-06-22 04:16, Michael Paquier wrote:
> On Wed, Jun 21, 2017 at 4:57 PM, jasrajd <jasrajd@microsoft.com> wrote:
>> We are also seeing contention on the walwritelock and repeated writes 
>> to the
>> same offset if we move the flush outside the lock in the Azure 
>> environment.
>> pgbench doesn't scale beyond ~8 cores without saturating the IOPs or
>> bandwidth. Is there more work being done in this area?
> 
> As of now, there is no patch in the development queue for Postgres 11
> that is dedicated to this particularly lock contention. There is a
> patch for LWlocks in general with power PC, but that's all:
> https://commitfest.postgresql.org/14/984/
> 
> Not sure if Kuntal has plans to submit again this patch. It is
> actually a bit sad to not see things moving on and use an approach to
> group flushes.
> --
> Michael

There is also patch against LWLock degradation on NUMA :
https://commitfest.postgresql.org/14/1166/

But they are both about LWLock itself, and not its usage.

-- 
Sokolov Yura
Postgres Professional: https://postgrespro.ru
The Russian Postgres Company