Re: limiting hint bit I/O

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Merlin Moncure <mmoncure@gmail.com>, Jim Nasby <jim@nasby.net>, Kevin Grittner <Kevin.Grittner@wicourts.gov>, Josh Berkus <josh@agliodbs.com>, pgsql-hackers Hackers <pgsql-hackers@postgresql.org>
Date: 2011-01-19T16:52:27Z
Lists: pgsql-hackers
Robert Haas <robertmhaas@gmail.com> writes:
> ... So what we
> want to do is write a percentage of them, in a way that guarantees
> that they'll all eventually get written if people continue to access
> the same data.

The word "guarantee" seems quite inappropriate here, since as far as I
can see this approach provides no such guarantee --- even after many
cycles you'd never be really certain all the bits were set.

What I asked for upthread was that we continue to have some
deterministic, practical way to force all hint bits in a table to be
set.  This is not *remotely* responding to that request.  It's still not
deterministic, and even if it were, vacuuming a large table 20 times
isn't a very practical solution.

			regards, tom lane