Re: WAL prefetch

On Fri, Jun 15, 2018 at 11:31 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2018-06-14 10:13:44 +0300, Konstantin Knizhnik wrote:
>>
>>
>> On 14.06.2018 09:52, Thomas Munro wrote:
>> > On Thu, Jun 14, 2018 at 1:09 AM, Konstantin Knizhnik
>> > <k.knizhnik@postgrespro.ru> wrote:
>> > > pg_wal_prefetch function will infinitely traverse WAL and prefetch block
>> > > references in WAL records
>> > > using posix_fadvise(WILLNEED) system call.
>> > Hi Konstantin,
>> >
>> > Why stop at the page cache...  what about shared buffers?
>> >
>>
>> It is good question. I thought a lot about prefetching directly to shared
>> buffers.
>
> I think that's definitely how this should work.  I'm pretty strongly
> opposed to a prefetching implementation that doesn't read into s_b.
>

We can think of supporting two modes (a) allows to read into shared
buffers or (b)  allows to read into OS page cache.

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