Re: limiting hint bit I/O

Robert Haas <robertmhaas@gmail.com>

From: Robert Haas <robertmhaas@gmail.com>

To: Cédric Villemain <cedric.villemain.debian@gmail.com>

Cc: Bruce Momjian <bruce@momjian.us>, Tom Lane <tgl@sss.pgh.pa.us>, 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: 2011-02-06T00:35:43Z

Lists: pgsql-hackers

On Sat, Feb 5, 2011 at 5:04 PM, Cédric Villemain
<cedric.villemain.debian@gmail.com> wrote:
> Robert, I am unsure with the hint_bit_write_allowance counter. It
> looks a bit fragile because
> nothing prevent  hint_bit_write_allowance counter to increase a lot,
> so that is not 100 but X*100 next hint bit will be written. Isn't it ?

hint_bit_write_allowance can never be more than 100.  The only things
we ever do are set it to exactly 100, and decrease it by 1 if it's
positive.

> Also, won't buffer_allocation_count hit INT limit ?

Sure, if the backend sticks around long enough, but it's no big deal
if it overflows.

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