Re: Set hint bits upon eviction from BufMgr - Mailing list pgsql-hackers

From Robert Haas
Subject Re: Set hint bits upon eviction from BufMgr
Date
Msg-id AANLkTi=wpoenKQQFFQ5wfBJXbL++YrMui75EvEjKU7ti@mail.gmail.com
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In response to Re: Set hint bits upon eviction from BufMgr  (Merlin Moncure <mmoncure@gmail.com>)
Responses Re: Set hint bits upon eviction from BufMgr
List pgsql-hackers
On Mon, Mar 28, 2011 at 9:48 AM, Merlin Moncure <mmoncure@gmail.com> wrote:
> I'd like to experiment on this and see what comes out.

Great!

> If the
> bgwriter was to be granted the ability to inspect buffers and set
> hints, it needs to be able to peek in and inspect the buffer itself
> which it currently doesn't do FWICT.

That matches my understanding.

> I was thinking about setting a
> flag in the buffer (BM_HEAP) that gets set by the loader which flags
> the buffer for later inspection.  Is there a simpler way to do this?

Hmm.  That's slightly crufty, but it might be OK.  At least, I don't
have a better idea.

> I think you guys are correct: the logic belongs in the bgwriter.
> Generally speaking, it looks like the best route to minimizing hint
> bit pain is to if at all possible write them out set so they don't
> have to be rewritten later (Stephen's approach to leverage in
> transaction table creation is another way of attempting to do that).

Yeah.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company


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