Re: Visibility map and hint bits - Mailing list pgsql-hackers

From Merlin Moncure
Subject Re: Visibility map and hint bits
Date
Msg-id BANLkTi=o_PaeL28OKiODfAg6EMFMvbabcA@mail.gmail.com
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In response to Visibility map and hint bits  (Bruce Momjian <bruce@momjian.us>)
Responses Re: Visibility map and hint bits  (Bruce Momjian <bruce@momjian.us>)
List pgsql-hackers
On Thu, May 5, 2011 at 11:59 AM, Bruce Momjian <bruce@momjian.us> wrote:
> There has been a lot of recent discussion about the visibility map (for
> index-only scans) and hint bits (trying to avoid double-writing a
> table).

I still think a small tqual.c maintained cache of hint bits will
effectively eliminate hint bit i/o issues surrounding bulk loads.  Tom
fired a shot across the bow regarding the general worthiness of that
technique though (see:
http://postgresql.1045698.n5.nabble.com/Process-local-hint-bit-cache-td4270229.html)
:(.  I can rig up a cleaned up version of the patch pretty
easily...it's a local change and fairly simple.

I don't think there is any way to remove the hint bits without
suffering some other problem.

merlin


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