Re: [HACKERS] Execution time.

Marc G. Fournier <scrappy@hub.org>

From: The Hermit Hacker <scrappy@hub.org>
To: Shiby Thomas <sthomas@cise.ufl.edu>
Cc: "Vadim B. Mikheev" <vadim@sable.krasnoyarsk.su>, pgsql-hackers@postgreSQL.org
Date: 1998-02-04T16:38:04Z
Lists: pgsql-hackers
On Wed, 4 Feb 1998, Shiby Thomas wrote:

> 
> => > I invoked postmaster as:
> => >  postmaster -B 30000 -o "-s -F -S 16384"
> =>                  ^^^^^
> => 240M of shared memory ?!
> => 
> Is the size of the hash bucket dependent on the number of buffers available ?
> If so, with -B 30000, it might create huge hash buckets and hence the
> hash join could degenerate to a nested loops join. Is that possible -- just
> checking. What could be good values for -B and -S. The largest table I am
> joining is about 60M

	My production server runs with a -B 256, and a -S 10240