Re: Research/Implementation of Nested Loop Join optimization - Mailing list pgsql-hackers

From Tom Lane
Subject Re: Research/Implementation of Nested Loop Join optimization
Date
Msg-id 4383.1217033089@sss.pgh.pa.us
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In response to Re: Research/Implementation of Nested Loop Join optimization  (Alvaro Herrera <alvherre@commandprompt.com>)
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Alvaro Herrera <alvherre@commandprompt.com> writes:
> Tom Lane escribi�:
>> 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


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