Re: [HACKERS] Research/Implementation of Nested Loop Join optimization

Alvaro Herrera <alvherre@commandprompt.com> writes:
> Tom Lane escribió:
>> Good joke, but to be serious: we expect that forward scans will result
>> in the kernel doing read-ahead, which will allow overlapping of
>> CPU work to process one page with the I/O to bring in the next page.

> I wonder if this is spoiled (or rather, the backwards case fixed) by the
> attempts to call posix_fadvise() on certain types of scan.

Yeah, I started wondering about that too after sending off the above.
The fadvise patch might eliminate the distinction ... on platforms where
fadvise exists and actually works well.

regards, tom lane

--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers