Re: Sorting writes during checkpoint

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

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: Greg Smith <gsmith@gregsmith.com>, ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>, pgsql-patches@postgresql.org
Date: 2008-07-04T16:05:54Z
Lists: pgsql-hackers
Simon Riggs <simon@2ndquadrant.com> writes:
> Anyway, I note that we don't have an easy way of sorting by tablespace,

Say what?  tablespace is the first component of relfilenode.

> but I'm sure it would be possible to look up the tablespace for a file
> within a plugin.

If the information weren't readily available from relfilenode, it would
*not* be possible for a bufmgr plugin to look it up.  bufmgr is much too
low-level to be dependent on performing catalog lookups.

			regards, tom lane