Horton

Re: Index Scans become Seq Scans after VACUUM ANALYSE

Bruce Momjian <pgman@candle.pha.pa.us>

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From: Bruce Momjian <pgman@candle.pha.pa.us>
To: "J. R. Nield" <jrnield@usol.com>
Cc: Curt Sampson <cjs@cynic.net>, Michael Loftis <mloftis@wgops.com>, mlw <markw@mohawksoft.com>, PostgreSQL Hacker <pgsql-hackers@postgresql.org>, Tom Lane <tgl@sss.pgh.pa.us>
Date: 2002-06-22T23:17:11Z
Lists: pgsql-hackers 
J. R. Nield wrote:
> One other point:
> 
> Page pre-image logging is fundamentally the same as what Jim Grey's
> book[1] would call "careful writes". I don't believe they should be in
> the XLOG, because we never need to keep the pre-images after we're sure
> the buffer has made it to the disk. Instead, we should have the buffer
> IO routines implement ping-pong writes of some kind if we want
> protection from partial writes.

Ping-pong writes to where?  We have to fsync, and rather than fsync that
area and WAL, we just do WAL.  Not sure about a win there.

-- 
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